Modafinil is a prescription stimulant drug. I discuss informally, from a cost-benefit-informed perspective, the research up to 2015 on modafinil’s cognitive effects, the risks of side-effects and addiction/tolerance and law enforcement, and give a table of current grey-market suppliers and discuss how to order from them.

Modafinil is a wakefulness stimulant drug developed in the 1980s. It is prescribed for narcolepsy but is widely used off-label for its stimulating effects and to deal with sleep deficits. As such, many believe it helps their cognitive performance & productivity. (However, comparing it to the fictional drug NZT in the 2011 movie Limitless is a gross exaggeration.) I would describe its advantages over other common stimulants as: more powerful and less addictive & tolerating than caffeine or khat; much longer-lasting than nicotine; less likely to alter mood or produce ‘tweaking’ behavior than Adderall or Vyvanse; and much more legal & with almost no side-effects compared to methamphetamine or cocaine. On any specific aspect, there may be a stimulant superior to modafinil, but few stimulants come close to modafinil’s overall package of being a long-lasting, safe, effective, non-mood-altering, quasi-legal stimulant, and that is why it has become so popular.

Its development stems from adrafinil, a wakefulness drug developed back in the late 1970s. It worked reasonably well in animals and humans , and interestingly enough, in a different way from most stimulants. Inside the body, adrafinil is metabolized by the liver into modafinil. So using adrafinil is inferior to using a straight dose of modafinil both because it stresses the liver (which apparently caused its discontinuation by the usual manufacturer ) and because reportedly you need about 3 times more adrafinil to be metabolized into an equivalent dose of modafinil. Its chief advantages were that all patents on it expired long ago, and it’s very rarely proscribed—so it was relatively cheap & easy to get.

Modafinil is better, but the problem is that a number of forms are patented, and in addition, it’s a proscribed drug in the US & Canada . So you can either try to convince a doctor to give you a prescription or deal with dubious online pharmacies or suppliers in countries where modafinil is available over-the-counter. The former way is annoying and you pay full price, and the latter way is unreliable and still expensive—you may be buying at a lower price, but the risks of seizure at the border, shipping, possibly paying for laboratory assays etc. can more than make up for that.

Modafinil costs about $2 -12 a day ; non-prescription sources are too unpredictable to say.

Modafinil can be reliably determined in plasma and urine (Schwertner and Kong, 2005; Tseng et al, 2005), and is readily absorbed (40-65%, as measured by urinary recovery) after single (Wong et al, 1999a) or multiple oral doses (Wong et al, 1999b), reaching peak plasma concentrations 2-4 h after administration (Wong et al, 1999a). The presence of food in the gastrointestinal tract can slow the rate but does not affect the total extent of absorption. Steady-state plasma concentrations are achieved between 2 and 4 days with repeated dosing. It is highly lipophilic, and approximately 60% bound to plasma proteins, primarily albumin. Major pharmacokinetic parameters are independent of doses in the range of 200-600 mg/day (Robertson and Hellriegel, 2003). The major circulating metabolites modafinil acid and modafinil sulfone do not appear to exert any significant activity in the brain or periphery (Robertson and Hellriegel, 2003). The elimination half-life is approximately 12-15 h (Wong et al, 1999a), and single daily dosing is adequate and common in clinical practice.

Two-time 100 mg modafinil potently improved vigor and well-being, and maintained baseline performance with respect to executive functioning and vigilant attention throughout sleep deprivation in Val/Val [G/G] genotype subjects but was hardly effective in subjects with the Met/Met [A/A] genotype.

Interestingly, there seem to be some groups for which modafinil does little, and this ineffectiveness may not be due to counterfeit product or poor self-monitoring, but genetics ( Bodenmann et al 2009 , see also Bodenmann & Landolt 2010 on the same subjects):

Data from 6 RCTs, with a total of 910 patients with MDD [major depressive disorder] or bipolar depression, consisting of 4 MDD RCTs (n = 568) and 2 bipolar depression RCTs (n = 342) were analyzed. The meta-analysis revealed significant effects of modafinil on improvements in overall depression scores (point estimate = −0.35; 95% CI, −0.61 to −0.10) and remission rates (odds ratio = 1.61; 95% CI, 1.04 to 2.49). The treatment effects were evident in both MDD and bipolar depression, with no difference between disorders. Modafinil showed a significant positive effect on fatigue symptoms (95% CI, −0.42 to −0.05). The adverse events were no different from placebo.

Normal healthy volunteers (n = 12, 10 men and 2 women; 30-44 years) underwent a 3-day, counterbalanced, randomized, crossover, inpatient trial of modafinil (400 mg daily) versus placebo with 4-day washout period between 2 treatments. Mood was assessed daily using both the Positive and Negative Affect Schedule and a general mood scale, which consisted of 10 bipolar adjective ratings based on a severity scale ranging from 1 to 10. Modafinil increased general mood and Negative Affect scales relative to placebo and had a significant effect on Positive Affect scales. These results suggest that modafinil may have general mood-elevating effects accompanied by increased negative affect (anxiety). The findings may have implications for clinical practice, in particular for the adjunctive use of modafinil in treatment-resistant depression .

The effect of modafinil on mood is cloudy (part of the problem being, I suspect, varying doses and populations); “A Randomized, Double-Blind, Crossover Trial of Modafinil on Mood” (Taneja et al 2007) used doses of 400mg, finding:

There was a significant post-treatment change in the factor measuring ‘somatic anxiety’ and in individual ratings of ‘shaking’, ‘palpitations’, ‘dizziness’, ‘restlessness’, ‘muscular tension’, ‘physical tiredness’ and ‘irritability’, which was mainly due to significantly higher ratings of somatic anxiety in the 100 mg group compared with the other two groups [placebo & 200mg]. Further changes in mood were revealed after the stress of cognitive testing, with the 100 mg group showing greater increases in the ‘psychological anxiety’ and the ‘aggressive mood’ factors.

And the gripping hand: the 100mg dose may be the problem and be too high; the exact shape of the dose-response curve and between-subject variability remains unclear, with some anomalies like “Modafinil affects mood, but not cognitive function, in healthy young volunteers” (Randall et al 2003), noted no benefits on the CANTAB test suite due to the lower dose tested having greater anxiogenic effects:

In addition, modafinil (at well-tolerated doses) improves function in several cognitive domains, including working memory and episodic memory, and other processes dependent on prefrontal cortex and cognitive control. These effects are observed in rodents, healthy adults, and across several psychiatric disorders.

Modafinil has a couple different but closely related benefits. You can sum them up as pretty much it cuts your sleep need by about 2⁄3s :, or it allows you to go without sleep for a day with little mental penalty with increasing penalties thereafter. (If you aren’t sleep-deprived, it seems to just increase your alertness and energy levels, with mixed effects on other things.) It is overall a better stimulant than caffeine or the amphetamines , and targets different receptors than the amphetamines. The picture is good enough that some bioethicists are daring enough to go off their usual script (“the long-term effects are unclear; there may be unexpected side-effects or long-term consequences —more study is required”) and abandon the Precautionary Principle and suggest that maybe healthy people using modafinil might be a good thing .

Data is hard to come by for specific countries: for example, England apparently permits online purchase of modafinil and online sales are forbidden, but instances of enforcement are hard to find and equivocal (for example, the online site ModafinilUK was hit in the 2012 raids, but news coverage suggests the English owner would not be charged with anything ). Rumor has it that one UK-based modafinil seller has been jailed for his sales, but I was unable to find any confirmation of this.

Internationally, the situation is too various to generalize, ranging from over-the-counter legal to unregulated to as or more controlled than the US; Japanese law, since 2006, has imposed considerable penalties on modafinil use/sale (with a small exception for travelers carrying small quantities ). Currently, these incidents been reported:

A Redditor in Australia (ACT) reports on 2018-06-06 that a friend was raided after an intercept of 300 armodafinil tablets; while armodafinil seems to be legal in Australia to import in personal use quantities , the amount may have been too much, and it’s unclear what will happen.

So my searches turn up only a few arrests/convictions since the 1998 FDA approval, which arguably have some extenuating or complicating circumstance. This is far from a complete search; the law student cautioned me that many opinions are never published, and there may be keyword issues where all the matching keywords are about “substance possession” etc and not “modafinil”. Finally, one major legal database is missing, LexisNexis Legal. But it is suggestive , when you contrast it with other drugs; for example, it’s trivial to find charges or convictions for Adderall .

Most of the documents in the case are sealed on PACER, making it hard to say how much of a role modafinil played. Etizolam has been the focus of considerable LE attention, especially on the darknet markets, so may well have been the primary reason.

Between 2015 and 2019, Belani admitted that he and his co-conspirators, through LeeHPL Ventures, imported into the United States various drugs available only by prescription, including tapentadol , a Schedule II controlled substance, as well as tramadol , carisoprodol , and modafinil, all Schedule IV controlled substances. In addition, Belani admitted that between 2015 and mid-2017, he worked with two co-conspirators in the United States—William Kulakevich and Julia Fees—to unlawfully smuggle a drug known as etizolam into the United States so that Kulakevich and Fees could resell it via a website they operated— www.etizy.com .

The Indian businessman Jeetendra Harish Belani was arrested in the Czech Republic on 2019-06-03 (indicted 2019-06-26 ), extradited to the USA, and in July 2020 was sententenced to time served, 3 years’ probation, & a $100,000 fine:

An ex-doctor in Pennsylvania was arrested & sentenced to rehabiliation/parole in December 2019 for forging modafinil/armodafinil prescriptions he used to help with shift work; he needed multiple prescriptions because he was “taking approximately 800 mg per day or three to four pills per shift since he had built up a tolerance to the drugs.” (No mention of why he didn’t order online but resorted to forgery.)

as part of “Operation Granite Shield” in New Hampshire, coordinated raids of 88 agencies aimed at street-level drug dealing (opiates specifically) arrested more than 150 people ; these led to followup arrests, including 13 more on 2018-05-17, of whom 1 29yo NH man was charged with 2 warrants and also modafinil possession (apparently his second charge for ‘possession of a controlled drug’ although none of the news reports specify what the first charge was for)

in January 2018, an Illinois police deputy pled guilty to 1 charge stemming from 3 charges in April 2015 that she was stealing prescription medicine evidence and a search of her home turned up modafinil/zolpidem/tapentadol (media: 1 , 2 ), for which she claimed to have prescriptions and apparently did “for at least one of the medications”. The 2018 article doesn’t specify what medication the plea bargain referred to.

It is unlawful for any person to willfully, as defined in section 12.1-02-02, possess a controlled substance unless the substance was obtained directly from, or pursuant to, a valid prescription or order of a practitioner while acting in the course of the practitioner’s professional practice, or except as otherwise authorized by this chapter, but any person who violates section 12-46-24 or 12-47-21 may not be prosecuted under this subsection. Except as provided in this subsection, any person who violates this subsection is guilty of a class C felony.

I’m not sure why he’d be charged with that, when the immediately following section #7 fits simple possession much better with the same penalty, but applying to possession of a scheduled drug without a prescription:

It is unlawful for a person to willfully, as defined in section 12.1-02-02: a. Serve as an agent, intermediary, or other entity that causes the internet to be used to bring together a buyer and seller to engage in the delivery, distribution, or dispensing of a controlled substance in a manner not authorized by this chapter; or b. Offer to fill or refill a prescription for a controlled substance based solely on a consumer’s completion of an online medical questionnaire. A person who violates this subsection is guilty of a class C felony.

An appeal on Reddit and Imminst.org/Longecity for further examples turned up one claim by a one redditor that “A friend of mine passed out in his car after drinking and had a modafinil on him. He was busted with a felony.”; he later gave me the case docket: North Dakota Case No. 18-08-K-01620 2008 (sourced from their online case system ), busted for some sort of substance felony charge (modafinil is not specifically mentioned in the entry) & drug paraphernalia misdemeanor; pled guilty and got a 1 year sentence with work release . Confusingly, the specific felony charge makes no sense to me; the possession charge is specifically a violation of North Dakotan law “19-03.1-23(6)”, which an online copy says is

He found much the same results as me: patent disputes etc. He turned up Jackson’s charge & Wagner’s conviction as one would expect, but nothing else relevant. (He also found a curious appeal over an attempt to kidnap & murder a World of Warcraft player where the defendant tried to argue it was due to various mental disorders as well as his new modafinil prescription. The appeals court rejected this, noting his stalking & elaborate preparations long predated the prescription and most people with Asperger’s or bipolar—much less modafinil prescriptions—never attempt to kidnap or kill someone.)

An online acquaintance asked a law student friend for help; he searched Westlaw for “modafinil and possession” and “provigil and possession” over all federal and state cases.

There were 272 hits: 65 ‘Acts’, 27 ‘Administrative Rules’, 26 ‘Statutes’, and 26 ‘Proposed Regulations’; the remaining 128 were ‘Case Law’. Looking briefly at the first 4 categories, they didn’t seem very relevant, so I examined only the Case Law. The results began in 2003, and largely rehashed all the previous hits, although with many more insurance and discrimination and other medical disputes.

The given name, the various charges, the use of a public defender, and the city he lives in suggest Wagner is a poor black man who is rather shiftless; further, Missouri has something of a reputation—I do not know how deserved it is—for a justice system that is especially harsh on blacks.

Unfortunately, information about the trial is scarce. The best I’ve been able to do is use the Missouri case-search system, where we see his previous criminal record:

One Missouri case resulted in a 7 year conviction for modafinil possession, and nothing else; it’s covered in an appeal, “172 S.W.3d 922 (2005): Kendrick WAGNER, v. STATE” . The appeal is about how he got his sentence increased by 1 year for failing to show up for sentencing, “due to his own negligence in failing to arrange for transportation that day.” This is dramatic and distressing: a plea bargain for 6 years? For modafinil?

“State v. Jackson, NJ: Appellate Div. 2010” involved a man with a history of depression attempting to shove a woman onto railroad tracks and then resisting arrest; he was charged with “resisting arrest, aggravated assault and possession of a schedule IV controlled dangerous substance, namely modafinil”, but the appeal exclusively concerns the ‘resisting arrest’ charge (1 year probation) which was part of a plea bargain, which I take to mean he was not convicted on any modafinil-related charges. (The judgment mentions that he had been prescribed the stimulant Wellbutrin ; possibly it turned out he had a modafinil prescription, he had been given samples, or maybe the prosecutor simply didn’t want to bother.)

More useful were various appeals which mentioned modafinil; among the hits I checked were included an author bio, 2 disputes with Social Security or an insurance company rejecting a claim, 2 academic papers (an aside in a paper on mental problems in prisons and a case study of pharmacists & mysterious deaths), and finally 2 actual criminal convictions related to modafinil, 1 conviction apparently for modafinil possession:

Besides the usual patent/price-fixing and sports hits, Google Scholar turns up some interesting cases where it is noted the plaintiff has been prescribed modafinil or has ceased taking their prescribed modafinil (for issues like ADHD or fatigue), and a 2002 patent granted to a Chinese investor for modafinil as an fertility treatment (!), which are not things I expected to find.

I downloaded them all to a 4.3M text file to review; there might be mentions of criminal cases. Searches through the file for the keywords ‘charge’, ‘court’, ‘convict’, and ‘criminal’ turns up the usual professional sports & Cephalon monkey business, but no outright regular criminal cases. The one exception may be cases related to the BALCO investigation—a company that specialized in prescribing banned substances to many professional athletes and concealing it, one of which was modafinil. Looking at Wikipedia and the articles, all substance-related convictions seem to have been for steroids, not modafinil, but I could be mistaken. In any case, BALCO is a pretty exceptional scandal and not very relevant to ordinary modafinil users.

I looked at the matched pages for all; they were generally related to bio-ethics, professional sports, or patents and price-fixing (due to Cephalon’s bad behavior). No criminal cases.

PACER is a database of federal court filings; it is proprietary and has no full-text search. Fortunately the filings are all public domain and have been jail-broken into a searchable database; the RECAP subset found 2 search results :

Headline cases of online drug markets or pharmacies, like the September 2011 indictment of ‘Farmers Market’, confine their charges to site administrators & employees, but headline cases are by definition unusual. On the other hand, reading through forums and other places, I see no mentions of actual convictions, which is a little odd given that estimates of illegal use in the USA alone run into the scores of thousands of users per year—could this scheduling be just a dead letter, or the sort of law kept as an additional punishment the system can use if it doesn’t like you or thinks it can’t make the real charges stick? The general belief among modafinil users is that as long as one is importing less than 2-500 doses, the most US Customs will do is seize the order and send a “love letter” daring you to come get it. I am not a lawyer, but I do know how to use search engines, so in February 2012 I did some looking. Here are my results:

Scary. State laws may be more lenient. I am told that “§11377 of the California Health & Safety Code, which states that the punishment for possession of modafinil is not more than one year in county jail OR a punishment pursuant to subdivision (h) of §1170 of the Penal Code, which states that conviction could lead to imprisonment in county jail for 16 months to three years.” Better, but still scary.

Not more than 5 years. Fine not more than $250,000 if an individual, $1 million if not an individual.

But what does the research literature say? It seems to report no euphoria , tolerance, withdrawal, or dependency:

But there are two pieces of good news in the anecdotes. By and large, they only report tolerance, and not addiction/dependence. Caffeine tolerance builds up rapidly, and worse, there is dependence: one painfully declines to below baseline mental performance when one stops using the caffeine; but there seems only to be tolerance to modafinil—I have seen no first-hand anecdotes reported performance declines after tolerance and ceasing use. (One’s baseline productivity may be so low compared to productivity while using modafinil that one feels like there is dependence, though.) Secondly, some anecdotes report that modafinil can be used indefinitely on a weekly or more frequent basis without developing tolerance. So this downside may not be large. There’s no evidence that modafinil tolerance is linked to medium-term changes in the brain (like use of irreversible MAO inhibitors , which affect MAO levels for weeks), so I’ll ignore it in the following cost-benefit analysis. A drug which offers a high return on investment but can only be used once a week is still offering a high return on one’s investment.

Anecdotally, the real troll under the bridge for modafinil seems to be that one can develop tolerance, where it no longer has the stimulant or anti-sleep effects that made it so awesome (it has been speculated to be related to liver metabolism ). For example, poker player Paul Phillips took 2-300mg daily for a long period and said the effects “have attenuated over time. The body is an amazing adjusting machine, and there’s no upside that I’ve been able to see to just taking more.” (Such comments are common online among those who have used modafinil heavily, to the point where I have successfully predicted tolerance for such users, and I carefully avoid using modafinil more than weekly, if that.) The lack of academic support for these observations of tolerance is a little strange—users hardly have any incentive to make up downsides about their favorite drug.

Indeed, modafinil’s relative lack of side-effects has led to it being called the most perfect “nootropic”, in the etymological sense of a drug which has no bad aspects and only improves the mind. But there is no free lunch, after all. (There may be bargain lunches which we are thrilled to buy, but they aren’t free. If they were, why didn’t Evolution grab them already? For discussion of how drugs can be bargain lunches, see The Algernon Argument .)

“You’re taking a high risk”, Baroness Susan Greenfield, neuroscientist and Director of the Royal Institution of Great Britain, told me. “Our brains are who we are. They are hugely delicate. You’re risking your whole life.”

So overall, assuming one does not use modafinil too frequently, or to skip more than 1 night at a time , and remembers to remain hydrated & eat extra food to compensate for the additional activity & appetite suppression, modafinil does not seem to have any major risks for healthy users as far as I can tell, and certainly no such scaremongering like the following quote is justified:

Few long-term studies have been done of modafinil’s safety outside of the drug approval trials. The LD50 is so high that it is currently not known for humans ; one troubled woman attempted suicide with an overdose of 4.5 grams of modafinil but failed , and another man apparently tried & failed with a blister pack (>2.4g?); no deaths are known to be attributable to modafinil (which curiously makes it safer, acute dose-wise, than caffeine ). Of course, one cannot rule out that there might be drastic consequences which manifest only decades later, but given that modafinil could be called a pseudo-life-extension drug due to its famous wakefulness effects, there’re arguments that modafinil is a net gain even with any (a priori unlikely) long-term backfiring.

Consistent with the listed onset and claims that females have increased risk, the one report of modafinil-induced SJS on Reddit was a female who developed it after 10 days. 3 pediatrics seems like a substantial fraction of the cases; calculating what rate in millions these 6 cases represent is harder. I haven’t yet found direct estimates of how many people took modafinil 1998-2007; an article on Cephalon’s anti-competitive practices says “United States sales of Provigil increased from $25 million in 1999 to $475 million in 2005 to $800 million in 2007.” 2002 sales were $196.3 million (Pollack & Ault 2003) and 2003 sales $300 million (Vastag 2004). We could try to guesstimate the overall sales between 1999-2007 as 25+475+8003⋅(2007−1999)=$3,466.7m; Normann & Berger 2008 put 2007 global sales at >$700m. The FDA cases are for the USA only as far as I know, so we want only US consumption (although helping external validity, ~90% of prescriptions are for off-label use according to Cephalon in 2004 ). If each US pill is $10 in sales (probably low), then 346.67m pills were sold; if each person uses one pill a day for 2 years on average, then we divide the pill count by 2 years of days, 346,670,0002⋅365.25=346670000730.5=474,565 people. Half a million is in roughly the right range, which is fine for a guesstimate—we could easily double our result or more by changing some of our assumptions (how many people used modafinil before 1999? How many sales were there after 2007? Does the average person prescribed it really use it for as much as 2 years, or do people tend to switch or get better much faster than that? etc.). A better estimate can be extracted from the MIDAS database of drug sales which tells us that Provigil sold from Q1 2011-Q1 2012 $1,411,547,000 in 2,376,000 “units”; I believe units are monthly prescriptions of 30 pills, since that gives me a per-pill estimate of $19.8/pill which is consistent with people’s reports of monthly prescriptions costs (eg. $440 for 30 is $15 a pill, or $1000 for 30 is $33 a pill, which bracket that average). So that implies 71,280,000 pills sold (which at a daily dose affects 195,154 man-years); there were 6 cases previously which we estimated at 346.67m pills but from $10 a pill which we now know to be too low by half, so we cut the 346 to 173, and 6 cases per 173m implies 1 case per 29m, and if 2011-early-2012 were sold 71.28m pills, we’d expect 2.5 new cases in that period. (This ~2 annual rate seems reasonably consistent with the rarity of online anecdotes of actual SJS, as opposed to people being worried that their common—~1%—side-effects of rashes etc may progress to SJS.) For armodafinil, the first reported case-study of SJS came in 2018, with Holfinger et al 2018 reporting a 21yo female who developed symptoms 12 days after starting (fortunately, she apparently made a full recovery and “only subtle skin discolorations over previously blistered skin areas remained”).

From the date of initial marketing, December 1998, to January 30, 2007, FDA received six cases of severe cutaneous adverse reactions associated with modafinil, including erythema multiforme (EM), Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug rash with eosinophilia and systemic symptoms (DRESS) involving adult and pediatric patients. The 6 cases from the United States occurred in four females and two males aged 49, 42, 27, 17, 15, and 7 years old, respectively. The median time-to-onset of adverse dermatologic effects following initiation of modafinil therapy was 17.5 days, ranging from 5 days to 5 weeks…There were no deaths. 5 of 6 patients required hospital admission for management, including one patient with TEN who was admitted to the surgical burn unit 20 days after starting modafinil at recommended doses to treat a sleep disorder.

In the previous adult trial, with ~3x as many patients, no rashes were reported and no SJS. With a background incidence rate of 1 to 2 cases per million-person-years, to be distinguishable, the rate would only have to rise a little. I’d especially want to know whether those ‘adults and children’ is really just ‘children’. As it stands, it looks like the problem is primarily in juveniles, and they are not the ones considering whether to experiment with modafinil. For adults, adverse side-effects are generally in the 0-4% range of the population (see table 3, page 4 of the guide). Another FDA page gives us details:

The specific increased incidence rate in another FDA publication is specified to be 5.7 per 1 million patients as compared to the background rate of 1-2 per million patients.

In clinical trials of modafinil, the incidence of rash resulting in discontinuation was approximately 0.8% (13 per 1,585) in pediatric patients (age <17 years); these rashes included 1 case of possible Stevens-Johnson Syndrome (SJS) and 1 case of apparent multi-organ hypersensitivity reaction. Several of the cases were associated with fever and other abnormalities (e.g., vomiting, leukopenia). The median time to rash that resulted in discontinuation was 13 days. No such cases were observed among 380 pediatric patients who received placebo. No serious skin rashes have been reported in adult clinical trials (0 per 4,264) of modafinil. Rare cases of serious or life-threatening rash, including SJS, Toxic Epidermal Necrolysis (TEN), and Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) have been reported in adults and children in worldwide post-marketing experience. The reporting rate of TEN and SJS associated with modafinil use, which is generally accepted to be an underestimate due to underreporting, exceeds the background incidence rate. Estimates of the background incidence rate for these serious skin reactions in the general population range between 1 to 2 cases per million-person years.

The most serious reported side-effect I know of is Stevens-Johnson syndrome (SJS). Modafinil, like acetaminophen , is one of the unfortunate category of drugs believed to cause SJS . SJS is generally rare (“about 300 new diagnoses per year” in the USA). It’s not clear how much modafinil increases SJS risk the FDA report specifies that there was only 1 ‘possible’ syndrome during the clinical trials of around 1,585 people (a child who had a fever & rash; Cephalon argued strenuously that it was not SJS). Presumably if modafinil really did cause SJS at a rate of 1 in 1500, then the millions of users since would have caused >667 cases of SJS. Page 2 of Cephalon’s physician guide goes into all the details:

Interested readers can compare the FDA adverse events reports for modafinil / armodafinil and for aspirin , but should remember these are raw reports, unscaled by number of prescriptions, and adverse event reports are probably less likely to be reported by illicit users.) What are those adverse events?

But a low rate of adverse events is still a rate. (And—this is a truism that applies to every single drug or substance which I should not have to point out—everyone is unique in that some substance will be horrible for them while great for others and vice versa; this is as true for modafinil—eg. one person I know experienced ‘serious muscle pain’ which he described as proportional to the dose—as it is for much more dangerous drugs like aspirin . Lists of side-effects are available in the FDA prescribing info (linked below) and online , but are unhelpfully generic; to take the first half of the list of regular side-effects: “headache” (obvious for any stimulant), “dizziness” (generic), “difficulty falling asleep or staying asleep” (of course!), “drowsiness” (maybe you’re using modafinil too much?), “nausea” (does anything not cause nausea?), “diarrhea”, “constipation”, “gas”, “heartburn”, “loss of appetite” (some people want that), and “unusual tastes” (is that really a bad thing?). The “serious” side-effects are more interesting; again taking the first half: “rash”, “blisters”, “peeling skin”, “mouth sores”, “hives”, “itching”, “hoarseness”, and “difficulty breathing or swallowing”—these all sound like they may be related to the histamine effects of modafinil. But overall, I am left unimpressed by them: if you develop a rash, stop taking modafinil! If you have peeling skin, stop taking modafinil! If you’re taking it for its utility, you can stop at any time—the side-effects you are most worried about are the ones which may develop into a real danger or which are permanent. So let’s move on to a closer look at the more serious risks.

Modafinil has a few side-effects. (I omit adrafinil’s possible liver damage since it doesn’t apply to modafinil.) The FDA in general seems to take a pretty optimistic view about any side-effects or long-term issues . The known issues generally are:

(We could complicate the analysis by incorporating a discount rate and reduce the value of modafinil by assuming that one only uses it occasionally to avoid building up tolerance, but the basic point is made: there needs to be an improbably high risk to modafinil to neutralize its benefits.)

So the expected value of modafinil is approximately 21 times less than it needs to be. Or, to put it another way, if modafinil had a less than 1⁄21 chance of killing you, it could be worth while. Do you think modafinil has a less than 1⁄21 kill rate? I do.

Well, alright. We’ll add it in. Let’s consider the worst-case: modafinil is fatal. One human life is usually valued at around 10 million dollars. I personally can expect another 50 years of life. We could look at it this way: what if modafinil had an average fatality rate of 1 over those 50 years, and I value the overall 50 years at $10m (and 25 years at $5m, and 5 years at $1m etc.), and each day has the same chance of killing you, so you could die the first day at 150⋅365.25 probability. Applying the usual expected gain/loss formula, each day we incur an expected loss of 10,000,000⋅150⋅365.25, or $548. Ouch. That is noticeably larger than the $26.2 we expected to gain. This is the worst case; there’s no way modafinil is actually 100% lethal.

But what of the other costs? There’s the stinky pee, for example. I don’t think this is even worth including, but let’s assign it 5¢ (how long are you going to be in the bathroom anyway?). Then there are the unknown health effects. Sure, the skeptic says, the studies have turned up little to nothing, but what about the long-term effects?

So, our very first calculation goes minimum wage⋅hours saved, or 6.55⋅4, or $26.2. $26.2 > $3, so off-hand modafinil seems worthwhile: the return is 873%.

As in my Melatonin , we’ll assume the value of our time is measured by the minimum wage . We’ll also assume modafinil costs $3 a day (this adds 50% to be conservative). Finally, we’ll assume the average sleep savings per day is 4 hours—roughly half one’s sleep; this seems reasonable since sometimes people will use modafinil to skip that day’s sleep and sometimes they’ll sleep normally and will take it for greater performance while they are awake.

So what’s the cost benefit analysis here? We need to take into account the financial expense of modafinil, the biological side-effects, and the benefit of less sleep.

Hence, if you order a 40x200mg Sun Modalert, it will generally run you something like $80 from a seller; then the bare minimum that modafinil seller could manage is a cost of (4+14)⋅1.05+(3002000)+(8⋅3652000)= 20 for a maximum possible margin of <74%. Being more conservative and assuming a 50% profit margin, this is consistent with (ie, greater than) both the affiliate percentages from past modafinil sellers and with the general affiliate percentages quoted by spam researchers, so it seems safe to assume that once a modafinil seller is up and running with a secure bugfree ecommerce website, a reliable dropshipper & modafinil source, and a good reputation, then it is profitable.

your standard blister-pack of 200mg Sun modafinil will run one around $4 in an Indian pharmacy. Since real fake medicine costs about as much and the cost of the modafinil is one of the smallest costs involved, we can assume that it is probably real and the Indian pharmacy prices apply.

(There is another, more pessimistic bound—the cost of fake medicines, which aren’t as cheap as one might guess, one example being a $59.95 product costing $2.50 sometime before 2003. )

Such a pharmacy price would be 10⋅2003 or 667 mg/$. So this sets another bound—it’s highly unlikely any online pharmacy would be able to beat an Indian pharmacy. Modalert packaging (see above) comes with retail prices in rupees stamped on it, presumably for tax purposes; at 81 rupees for 10 pills, and ~50 rupees to the dollar, that’s ~$2 per 10 or 20 cents per 100mg pill. The 200mg pills are stamped 129 rupees, or ~$2.5 or 25 cents per 200mg pill. Another reader reports similar Indian prices in January 2012: 85 rupees for 10x100 and 130 rupees for 10x200. A reader setting up a business told me in January 2012 that he had arranged with a UK-India importer for modafinil at $0.35-45 per pill in bulk, which is consistent with the stamp prices plus overhead & profit for the importer. A similar reader said, when I asked in February 2012, that the going price was 131 rupees for 10x200 and my February 200mg Modalert arrived with stamps for 131 rupees per 10 pills. My armodafinil (Waklert generic brand) bought on Silk Road are stamped 150 rupees (per 10x150mg) or ~$3, which is less of a premium than I would have guessed. An Indian redditor claims February 2013 Sun Waklert/Modalert at $0.28 per pill, and the Indian drug database HealthKartPlus prices Sun 150mg Waklert at 150 rupees per 10 and 200mg Modalert at 131 per 10. In September 2015, another redditor reported 40x200mg at $9.6.

the modalert from india, which is sold through both european and indian online pharmacies, costs about 12$ / 10 pills—200mg. now the same stuff in an indian pharmacy costs only $3 / 10 pills—200mg ( http://www.longecity.org/forum/topic/44117-modafinil-sources/page__st__20__p__454877#entry454877 )

These pharmacies are almost all sourcing their modafinil (if it’s actual modafinil) from Indian sources. More directly, there are scattered reports online about pricing in places like Russia or, most relevant, India:

Interestingly, there is only a weak pattern of commissions shrinking with prices, which suggests we may be seeing price discrimination at work ; if EDAndMore can offer both the cheapest prices and higher commissions, that suggests there is considerable margin to cut. Further, EDAndMore offers shipping ‘for free’, but of course, there is no such thing as a free lunch so what that actually means is that the shipping is built into the price. If we assume that shipping costs them $10 a package of 200x200 and exclude it from their modafinil cost, and we cut 20% for commission, that suggests a price of 200⋅200180−(180⋅0.2)−10, or ~300 mg/$—substantially higher than the 222 mg/$ available to the consumer.

For pharmaceutical affiliate marketing programs, particularly the Russian/East-European partnerka ecosystem like GlavMed which dominated modafinil sales until the early 2010s, commissions historically were around 30-50% . I signed up for 3 affiliate programs between April 2011 and January 2012 ; in order, by price per mg as given in the above chart (cheapest first):

So what’s the raw cost of modafinil to these online pharmacies? We can get a first estimate by looking at affiliate commissions. Commissions are part of the cost structure, so we can subtract the commission from the price and get an upper bound on how much the modafinil cost. (A company might be willing to pay a commission so high it makes a sale unprofitable if it generates a lot of return business, but this seems unlikely in an online pharmacy scenario.)

One way to evaluate whether something is ‘too good to be true’ is to figure out what the cost to the seller is. It is impossible for them to sell it for less in the long run—they would lose money on each purchase. And they have overhead, too, so their price to you must be greater than cost. There are exceptions where you can buy for less than cost and not be scammed, but every exception has some exceptional reason driving it. If you can’t figure the reason out, you should be suspicious.

Below is data given to me by an acquaintance about 2 strips of 200mg Modalert which he obtained through 2 separate sources.

Counterfeits seem to be responsible for many negative experiences with modafinil; in the absence of effective assaying or contacting the manufacturer , this section is an experiment with providing data on what believed genuine product looks like, inasmuch as the counterfeits sometimes not do a good job of replicating the packaging & appearance of genuine products.

There are other sources; the Silk Road 1 DNM & its successors usually have generic modafinil & armodafinil , at reasonable prices; but given the anonymizing measures, use of Bitcoin rather than dollars, and the inherent flux of an online marketplace, I cannot possibly incorporate it into the chart. However, I am interested in modafinil price trends over time and have been monthly compiling product pages from SR/BMR/Atlantis/Sheep/SR2 for future analysis:

Reports of Westerners successfully taking this route are rare (the only claims of success I have seem are in the Longecity thread linked previously). Additional information is welcomed.

It seems unsafe to consume any modafinil or armodafinil bought over Alibaba.com without third-party testing one arranges oneself (and definitely not through or provided by the Alibaba.com seller). For the difficulties of testing modafinil, see the later section.

…I have worked with a lot of different Chinese suppliers; not this one specifically, though. Alibaba gold rating means absolutely nothing, and Alibaba will not be helpful in a dispute. I have been scammed by multiple 5 year gold suppliers on there. Even when I showed Alibaba 3rd party testing proving they sold me baking soda as pitolisant or EDTA as coluracetam, I was SOL. I was out the money, and Alibaba did nothing to demote the supplier rating. So as far as anyone should be concerned, that rating is useless…We were also scammed by a supplier on Look Chem. Same story. We showed them proof it was fake, but they did nothing about it. The supplier is still listed as a verified supplier. So I consider the whole “verified” thing on all the sites to be BS. We have a few trusted suppliers that we stick to now. The others are just a gamble.

the major Chinese marketplace Alibaba.com offers a constantly changing selection of wholesalers who claim to sell modafinil; unfortunately it (the import-export section in particular) is a laissez-faire market where caveat emptor!, with many stories of burned buyers. One importer says

the Canadian supplier reChem Labs offers to Canadian customers only, for research purposes of course, 1g of armodafinil for $20, 3g for $45, 5g for $60, and 10g for $100. reChem labs “strictly forbids consumption of any of the products.”

the Chinese supplier “Sun Nootropic” formerly advertised 1kg for >$1,057 or 0.2kg for $200; they received positive reviews but one Longecity poster said “Paypal no longer allows anything to do with Modafinil” but “they can still sell it, at the same prices, through paypal, only if Modafinil isn’t mentioned at all” reportedly took it down due to Chinese regulations in March 2013 (they currently advertise 100g adrafinil for $133 )

Due to severe problems with payment processors, online pharmacies (including modafinil sellers) have been exploring Bitcoin as a solution. Bitcoin, being relatively new, has a volatile exchange rate, and pricing can be confusing. This table breaks out Bitcoin-denominated modafinil products separately. Generally, the sellers seem to automatically peg their Bitcoin prices to dollar-equivalents so the prices remain constant in dollars whatever the most recent Bitcoin price may be. (Conversions were made with the Bitstamp price of $415/₿ & £270/₿ on 10:30PM 2013-11-14.)

The riskier an investment is, the less each future dollar it might earn is worth; risk encourages ripping and running. Being quasi-legal or illegal is risky, quite on top of the usual small-business risks.

‘burning’ a reputation/consuming reputational capital; the service becomes more profitable exploiting customers temporarily even though this destroys the long-term value—the most extreme example is ‘cut and run’, simply never delivering on a batch of orders, this can be very profitable if a vendor is very trusted, as Silk Road 1 proved (The bigger a modafinil site, the more temptation because the more orders that will naturally come in before the news gets out.)

lack of investment into lowering prices or using new technology, treating the service as a ‘cash cow’ (possibly irrationally, or rationally if it’s powering another, more lucrative, investment)

lack of competition (possible, but doesn’t seem like an issue of late; this may be an exacerbating factor in the previous—there may be no other trusted sellers really competing)

A final note: reputations are not a perfect defense as one often hears of sellers that start off good but degenerate. There are many compelling economic or statistical reasons for this to happen:

It’s worth noting that shipping can make a major difference. For example, the now-defunct Airsealed’s $22 modafinil seemed like an excellent deal—but the price was almost doubled by their $15 shipping, but if one bought a lot the price also looked a lot better. The above table assumes that one orders only one unit of whatever it is; if one had been ordering several hundred dollars of modafinil from Airsealed, say, then Airsealed might look much better, and so for that purpose S&H is listed.

Fine, but how are we going to get any modafinil? (We’ll ignore getting a legitimate prescription or having a friend buy you some in India.) Buying modafinil is very much a grey-market. And it’s a black-market if one wants genuine Cephalon-manufactured Provigil/Nuvigil. (The real deal in pharmacies runs upwards of $10 per pill; so we won’t even bother to include it in the price table. Generic competition as of 2016 has reportedly driven it down to a more reasonable $1/pill .)

Generally, armodafinil > modafinil > adrafinil, brand-name > generic, but how do the generics go? The general scuttlebutt seems to be that the generics in descending order of desirability go:

Internet suppliers are not known for their transparency or reliability, and on top of the technical difficulties it is well-known that suppliers can be untrustworthy and actively deceptive; and the few retailers online of modafinil which are trustworthy tend to be more expensive (as a look at the above chart shows) or they require prescriptions for US buyers (like the Canadian online pharmacies). It’s hard to get any hard numbers on how likely a particular supplier is to be a scam, or how many customers of a particular site are happy. A BBC online poll (for what that’s worth) about “cognitive-enhancing drugs” (eg. modafinil, Adderall, and Ritalin) got 761 responses, of which 38% were users at any point (~289), of which “nearly 40% said they had bought the drug online, and 92% said they would try it again.” In the worst case scenario that the 8% who wouldn’t try it again were all online buyers, that’d implies be a 839=0.2051 or 21% unsatisfied rate or 79% satisfaction rate.

So we are faced with a classic problem of risk: given that any supplier may shaft us, how should we rationally order products to reduce our risk?

For modafinil we can come up with a few distinct ordering scenarios:

a one-shot order multiple orders, with oneself as an oracle (perhaps one has used genuine Provigil in the past and is sufficiently rational to avoid mistakes caused by things like the placebo effect) multiple orders, with laboratory assays as the oracle

One-shot ordering For a extended example of how one might calculate an order, see a Silk Road example For #1, the simple answer is best. You decide roughly how much you trust each supplier based on factors like how their website looks, what descriptions of them you found online, whether they seem ‘too good to be true’, etc—what is the percentage that they will pay? A known scam is 0%, a totally trusted source is 100% and everyone else is a shade of gray. Then you multiply their trustworthiness against their unit price (milligrams per dollar) price. Whomever comes out on top, you order from. So, if I thought EDAndMore had only a 60% chance of delivering real modafinil rather than caffeine pills, I would multiply their unit-price 222 against the trust-penalty of 0.6 and get 133.2 (222⋅0.6). And then I might decide United Pharmacies smells a bit better and give them a 70% chance, for a total of 145.6 (208⋅0.7); and perhaps Airsealed gets a whopping 95% trust from me, for a total of 71.25 (75⋅0.95). In this scenario, Airsealed is highly trustworthy compared to the other two, but because Airsealed costs nearly 3 times its competitors, it comes out poorly against United Pharmacies; UP is only a little more expensive than EDAndMore, but has a noticeable edge over EDAndMore in trust and so wins. For Airsealed to win, I would have to trust both EDAndMore and United Pharmacies somewhere less than 33%. I order and I get… something. This is where the one-shot strategy ends. You calculated, did your best, and either won or lost. If you plan to order again (and modafinil is such a useful drug that it is hard to see why one would not plan to use it indefinitely as side-effects, tolerance, and finances permit), you have a chance to update based on how the first order went. Presumably one has learned from one’s own experiences whether the product was modafinil or not. Modafinil is fairly distinct from caffeine; one gains tolerance to caffeine very quickly, and caffeine will not keep one going overnight with little mental penalty. So we’ll assume one knows. If it was modafinil, then great. You’ve found an honest supplier. (You might want to order a few years’ supply while you can.) If you really want an optimally cheap supply, you can try some of the other suppliers. Naturally you will not try any supplier whose per-unit price is more expensive, because you trust your current supplier 100% and must distrust the others at least a little, so the list of possible suppliers has been cut down.

Ordering with learning If it was not, then you have a problem. Are you the vengeful sort who assumes that suppliers are all-rotten? Then you blacklist them and order from the next cheapest supplier (by unit-price adjusted for perceived risk). If you’re not vengeful, if you believe the suppliers who say that they don’t have control of their supply chain and sometimes bad products slip in, then you have to do more work. If we interpret our distrust probability as instead ‘what percentage of delivered product is genuine’, then to continue the previous example, my trust probability would drop only a little if EDAndMore sent me caffeine/fake modafinil. Why? Because I estimated a 60% chance of them sending me modafinil, and 60% is another way of saying there’s a 40% chance they’ll send me not-modafinil. 40% chances happen quite often and I wouldn’t be very surprised if one happened when I ordered. On the other hand, I expected mostly pure product out of Airsealed (95% of their shipments being good), so if Airsealed sent fakes to me, then I would be quite shocked—5% chances don’t happen all that often (it’s like rolling a 20 in D&D). How much do I knock down my estimate of Airsealed? By more than EDAndMore. But how much more? Well, you have to apply Bayes’ theorem. (One basic property of Bayes’ theorem is that extreme probabilities are hugely damaged by opposed observations, while equivocal probabilities like 51% take a lot of data to knock down. For a good explanation, see “An Intuitive Explanation of Bayes’ Theorem” or “Visualizing Bayes’ Theorem”.) P(a|b)=P(b|a)⋅P(a)P(b) The former is a little complex, so we’ll simplify down again. Here’s our scenario: 95% of the orders delivered by a ‘good’ supplier will be real (all modafinil); but bad suppliers have only 5% of the orders be real. (Apparently this isn’t all that unrealistic; whether it’s because supply chains are unreliable or deliberate profit-maximizing behavior, often neither good or bad suppliers ship all fakes or all genuine modafinil.) Now, supplier A, whom you had calculated was probably good with 90% probability, sent you a fake. Keeping in mind that you might just be one of the unlucky 5%, now how much do you think that A is good? A rearrangement of Bayes’ theorem from the end of Eliezer Yudkowsky’s “Intuitive Explanation of Bayes’ Theorem” (he explains its derivation if you don’t trust me): P(a|b)=P(b|a)⋅P(a)(P(b|a)⋅P(a))+(P(b|¬a)⋅P(¬a)) How confusing and intimidating! Where does one start, with all the different symbols? Let’s break it down step by step. If you didn’t read either Wikipedia or Yudkowsky, you should have, but remember the pipe is read backwards: P(foo|bar) means ‘how likely is foo now that I have observed bar’ (you could mentally rewrite it to something like P(bar→foo)). b represents our observation, whatever it is. In this case, it’s the not-modafinil, the fake pills. a represents our new, reduced, belief that A is a good place to order from. So at the beginning we can make a few definitions: a = being a good supplier

b = receiving fakes If you look, the right-hand side of that equation has exactly 4 pieces in its puzzle: P(a) This is something we already know, ‘probability of being a good supplier’. Well, we specified a few paragraphs above that we had somehow concluded that A was a good supplier with 90% odds. P(¬a) This is the opposite of the previous. Now logically, if something has a 90% chance of being true, then it has a 10% chance of not being true. Either one or the other. So this is simply equal to 10%. P(b|a) Remember, we read the pipe notation backwards, so this is ‘the probability that a good supplier (a) will send us fakes (b)’. We also said that good suppliers send 95% good orders; by the same logic as above, that’s another way of saying they send 5% fakes. So this is simply 5%. P(b|¬a) Finally, we have ‘the probability that a bad supplier will send us fakes’. We said bad suppliers send 5% good orders, so again, subtracting from 100 and we know they must send 95% fakes. So this is simply 95%. To put all these definitions in a list: a = good supplier b = fakes P ( a ) = probability of being a good supplier = 90% = 0.90 P ( ¬ a ) = probability of being a bad supplier = 10% = 0.10 P ( b | a ) = probability a good supplier will send fakes = 5% = 0.05 P ( b | ¬ a ) = probability a bad supplier will send fakes = 95% = 0.95 We substitute in to the original equation: P(a|b)=P(b|a)⋅P(a)(P(b|a)⋅P(a))+(P(b|¬a)⋅P(¬a))=0.05⋅0.9((0.05⋅0.9)+(0.95⋅0.1))=0.045((0.05⋅0.9)+(0.95⋅0.1))=0.045(0.045+(0.95⋅0.1))=0.045(0.045+0.095)=0.0450.14=0.32 32% seems like a reasonable answer. Intuitively, I’d expect my trust to drop considerably below 50%, but still well above 5%, and 32% is well within that range. Phew! So, now we have a full system for situation #2. First, go through the expected utility calculation for all the prices you’ve gathered in which you trade off risk versus price. Then order, test for modafinil or not-modafinil, and do a Bayesian update on the supplier. Rinse, and repeat. This procedure terminates if there are any good suppliers (suppose you luck out and the second supplier you test, #4 on the per-unit list, is honest; now you only need to test 3 more suppliers since they are the only ones cheaper—why would you care about a equally reliable but more expensive supplier?). Of course, this does require you to already have beliefs about the reliability of a supplier. If one is willing to order blind, there’s a cute frequentist trick for rough estimation when you have a bunch of independent binary experiments: the rule of three, which goes simply that if you haven’t observed x despite looking n times, then 95% of the time x has a probability of less than 3⁄n. So if we had ordered 10 times from a seller and we assume the seller isn’t doing anything tricky like “send a new customer 11 real orders and then sell him only fakes” but is randomly sending reals and fakes, we can calculate the seller sends fakes less than 3⁄10 = 0.3 = 30% of the time. The weaker generalization is Laplace’s Rule of succession, which says the odds of a fake in the next order, given s failures and n total orders, is s+1n+2—the idea being that we should assume the worse, that we get a fake in the next order; then, if one looked at one of our orders randomly, there’d be an additional fake. In the previous example, that works out to 0+19+2=111=0.09=9%. (We can apply Laplace to all sorts of instances; one cute example is estimating whether a cop will pull you over for driving faster than him—if we assume that you were pulled over once, and you saw 4⁄5 others try & fail, then the odds you will be pulled over the next time is 4+15+2=57=0.71=71%.) We could also try applying the rule of three and Laplace’s rule of succession to estimating seizures by customs: I personally have ordered modafinil perhaps 7 times, one of which was not seized by customs but unusual circumstances meant I dastn’t get it; so I would obtain 3+17=0.57=57% by the rule of three or 1+16+2=0.25=25%. And the real rates? One supplier told me of 20-30 shipments without seizure, which would be 320=15% or 0+120+2=4.5%, and specifically claims a 3% rate; another supplier claims in their FAQ a 3% rate for all packages which are “stolen, returned, delayed till deadline”. Levchenko et al 2011 reports that of 120 purchase attempts, 56 purchases went through and only 3 were not delivered for any reason, for a failure rate of ~5%. Darknet market sellers seem to enjoy similar success rates, I infer from the general tenor of forum posts. In general, these low rates seem plausible given how rarely I hear of actual seizures. (People ask what the odds of seizure are far more often than seizures actually happen, it seems.)

Ordering when learning isn’t free See also the discussion as applied to evaluating sleep experiments and nootropics experiments. How do we extend this procedure to handle situation #3, where we no longer trust ourselves to test the supposed modafinil (for free)? This is a question on the value of information (4 examples). Let’s assume it costs $1000 to assay some pills and like in #2, we’ll assume the assay is infallible. Then we just repeat the #2 procedure except with the assay replacing our own subjective testing. Fair enough, right? But a wrinkle comes to mind: $1000 is a lot of money. Quite a lot, really. You could buy a lot of modafinil with $1000; even if we played it safe and bought from Nubrain, $1000 would get us 62⋅1000, or 62,000 mg, or at 200mg a day, 310 days’ worth . Are we sure we want to spend that? I mean, what if the price difference between the last 2 suppliers is just a few pennies—would we still want to spend $1000 just to be sure? Even if we plan to buy for years, decades, or the rest of our life, that $1000 might not be worth spending to optimize and save a few pennies. We could ask ourselves—is the possible penalty of a few pennies every order over our lifetime worth the $1000 right now? If we’re saying $1000 on every order, then we do want to spend it, and if we’re saving 1 penny on each order, but can you say instantly and with confidence that saving $50 is worth it? Or $55? Our intuitions are not that precise, and in cases like this, we ought to look for a more rigorous and precise way of expressing this trade-off. As it happens, there’s a nifty formula for our dilemma. We want to compare an infinite stream of small savings against a single large expenditure. The savings would make us slightly wealthier each time period. In fact, you could imagine that we were actually discussing loans or saving bonds or annuities: is the small expense or payoff each year worth the large upfront payment or investment? In economics terminology, the question is whether the ‘net present value’ of that payoff stream is larger than our present potential investment. Net present value can be approximated based on knowing one’s discount rate (which is a percentage) and then plugging in the numbers to the following formula: NPV=annualPayoffln(discountRate+1) What is my discount rate? If I introspect and ask myself, would I prefer $150 in a year to $100 right now; I say yes, so I know my discount rate is less than 0.5/50%; would I prefer $125 to $100 now? Yes, so it’s less than 0.25/25%; and so on down to around $107 versus $100, where the $7 feels a little too little. So let’s say my discount rate is 7%. What do our two suppliers look like? Maybe one charges me $220 for a year’s supply and the other—the one I haven’t yet tested—supplies it for $200. So $20 a year is at stake. Let’s plug it in: NPV=annualPayoffln(discountRate+1)=20ln(1+0.07)=20ln(1.07)=200.06765=295.6 But it would cost us $1000 to assay and find out whether there was a savings or not! Clearly it’s not a good idea to spend the money for the assay. $20 a year is just not enough. As it happens, at a discount rate of 7%, we would have to potentially save about $68 before the assay became a good idea. (For $20 a year to be worthwhile, your discount rate has to fall down to around 2%, and very few people are that patient and self-sacrificing!) If you look back at the supplier chart, it runs the gamut from 200+ mg per dollar to <16 mg; so for the first few purchases the assay might well be worthwhile. Thus we solve situation #3. You apply the #1 method to decide at any point which supplier to order from next by their risk-adjusted unit-price; then you update the risk-adjusted unit-price through #2’s idea of using Bayes’ theorem; then if testing is not free, you decide to stop testing and stop searching suppliers when, as given by #3’s present value formula, the testing (assays) start costing more than one can hope to gain. As it happens, $1000 is a gross exaggeration of how much assaying would cost; Erowid will do a kind of testing for $120, and we can run 2 simple chemistry tests to learn if there’s a sulfur group (which is a good proxy for modafinil) in a pill at an amortized cost of <$1 a pill or <$50 to start. It goes without saying that #1-3 are all simplified models which may not apply to every situation; but at some point, the would-be user of nootropics must start thinking for himself. Extended present-value example So let’s step through a problem using expected value and net present value. Starting with the price-chart, our top contenders per unit cost (mg/$) are (as of December 2011): 238, 4 NRX Pharmacy 215, United Pharmacies.co.uk 202, EDA ndMore.com 192, ThePharmacyExpress If we trust them all implicitly, we should order 4NRX. Let’s imagine our trust differs and come up with some hopefully non-random percentages about whether a supplier is honest: 238, 4 NRX Pharmacy, 65% 215, United Pharmacies.co.uk, 90% 202, EDA ndMore.com, 50% 192, ThePharmacyExpress, 90% We apply expected value to get our ‘expected unit cost’, as it were, and we get new rankings: 215, United Pharmacies.co.uk, 90% = 194 192, ThePharmacyExpress, 90% = 173 238, 4 NRX Pharmacy, 65% = 155 202, EDA ndMore.com, 50% = 101 One can change the ranking arbitrarily, of course, with extreme enough confidences. In this case, it wouldn’t be too hard to swap the first and second or restore 4NRX to the top of the heap. We’ve finished applying expected value. Let’s ask about net present value. We can ask: is it worth our while to assay, based on the difference of 194 expected mg/$ versus 173 expected mg/$? Maybe we should just order forever from UP.co.uk and forget about TPE. Well, let’s make the assumption that we will order 100 doses of 200mg of modafinil every year indefinitely, That is 100⋅200194=103 dollars with UP.co.uk and 100⋅200173=116 dollars with TPE, a difference of $13 per year. For the cost of our assay, we’ll go with the $50 amateur assay-test, and we’ll use my own personal discount-rate of around 5%: NPV>testCost=annualPayoffln(discountRate+1)>testCost=13ln(1+0.05)>50=13ln(1.05)>50=130.048790>50=266.4>50 We turn a profit of around $210. This little model isn’t correct since it covertly implies one of the two suppliers is sending fakes, yet back in expected value we gave 90% for both suppliers sending genuine products—a contradiction. We can try again with something fairer. Imagine you have the samples from both suppliers sitting at hand waiting to be tested. What do you expect to find? Well, if there’s a 90% chance that each of them is shipping genuine products, then there’s a 10% for each shipping counterfeits, which is pretty small and so the odds are good that our test will simply tell us that both suppliers are honest. Let’s look at all 4 possible outcomes: What are the odds that both are honest suppliers? (H H) Well, 90% times 90% is 81%. And that both are dishonest? (D D) 10% times 10% is just 1%. That the first one is dishonest and the second is honest? (D H) 90% times 10% is 9%. And vice versa? (H D) Well, same thing, 9%. (So the probability of either is 9% + 9% or 18%.) If both suppliers are honest, one gained nothing from the test, so we start with an 81% chance of not benefiting. Then, if the second one (the one you aren’t ordering from) is dishonest and the first one is honest, you still gain nothing (you picked correctly, huzzah!) so that’s 81% and 9%. If the first one (the one you are ordering from) is dishonest and the second one is honest, then you gain (9%), and the final 1% is also useful (you can scrap them both and look at suppliers further down the list). So all in all, there’s only a 10% chance of gaining from the assay! So here’s another opportunity to apply expected value: the value of our assay times that 10% chance it’ll actually lead to a financial gain: (266.4⋅0.10)>50=26.6>50 Oh well! A final thought about modafinil: “I am not interested in talking about my ideas. I am interested in your application of them to your life.”