Study 1: Information available on DNP from the internet

The internet search, after removing duplicates, yielded 92 websites of which 36 supplied DNP at the time of writing this article (August 2015). The search also identified a significant number of retailer websites which are no longer available. Details of the websites are provided in Additional file 2: List of retail web-based sites and discussion boards/forums. A comprehensive list was not attempted because of the fast changing nature of the DNP market. Rather, it is a snapshot of the situation illustrating the abundant supply and informal unchecked information available on the Internet. A considerable number of online retail sites (trading in anabolic steroids and other bodybuilding supplements) that do not sell DNP still provide information on DNP including a reference to alternative availability (e.g., from the UnderGround Lab). Forums are characterised by multiple threads started on various aspects of DNP use. These discussion threads typically initiated with an enquiry about DNP availability and use. Basic information; dosage; supplementation; side effects and allergic reactions; concurrent use of other bodybuilding substances and experiences are readily shared but responses tend to be void of or explicitly refuse suggesting retailers. Information on DNP manufacturers is shared among users, again, often initiated by someone with intention to purchase a particular brand. Independent of the legality of the transaction, word-of-mouth quality assurance and customer endorsement appears to be a prominent features in building trust for online purchases of DNP, which is in line with the general literature on online buying [49–52].

Detailed diary-like blogs on daily experiences with DNP are fairly common. Most of these blogs offer detailed accounts of the DNP ‘self-treatment’ regime, along with users’ expectations, fears and hopes, and experiences. Similarly to the phenomenon observed in the community of psyhconauts, the educated and informed recreational drug users [53, 54], lived experiences with DNP are often translated into advice for others who wish to experiment with the same substance. Without exception, these advices about DNP use aim to make the experience–risks acknowledged–better and safer.

Online availability of DNP

The incongruence between the geolocations of the ip addresses and shipment information (where available) indicates that DNP suppliers 1) possibly hide behind layers of web-pages; making policing difficult and 2) use multiple websites simultaneously. In some cases, DNP is sold with health warnings or a statement that the sale is not for human consumption and “packed in capsules only for means of safe transportation” (quote from the Q&A section of an online retail site), but the overall impression of the retail sites is that DNP is openly sold as an effective fat-burner/bodybuilding supplement.

Images on retail sites either show the compound as powder, capsules or pills; or the packaged product with manufacturer’s labels. Manufacturers, when identified, include Biomax Lab (Turkey), BR Europe which is now UmForte (US), BodyAdvance Performance (US), Gen-Shi Pharmaceuticals (Japan), AbaXen Pharmaceuticals (US), Aeolis Pharmaceuticals (US), TrigoPharm (The Netherlands) and Wildcat/British Research Laboratories (UK). DNP is sold and labelled ‘as is’ with only one exception found. The pack from Gen-Shi Laboratories shows L-Glutamin but the retail site clearly identifies the product as DNP, giving the compound name, manufacturer, dose, quantity. In addition to online retail stores, D-Hacks Lab (UK) and Crystal Heat Labs (UK) supply DNP through Facebook. Concerning mismatch in information on wholesale sites is not uncommon. For example, one retail site depicts DNP as yellow powder but with “steroid powders or liquid” overlaid on the image and discusses the recreational use of an entirely different substance, dextromethorphan (a cough suppressant), beneath the image under Application.

On most online retail sites, purchase requires registration and setting up a customer account. Many of them accept major credit cards. Alternative payments include bank transfer, Western Union, Moneygram or ‘bitcoin’. In terms of getting the DNP orders to customers, online retailers pride themselves for high success rates going through customs and offer a replacement guarantee (free replacement once with proof for the seized package) for most countries but Australia, Canada, New Zealand, Singapore and South Korea where only one shipment is made. Under shipping information, retailers explain in detail that they avoid identifying themselves as pharmaceutical-related or labs to avoid suspicion, using discreet packaging that does not identify the content and employ frequent changes to their packaging not to alert customs (i.e., using non-descriptive labels or disguise DNP as some other product, e.g., turmeric if DNP is shipped in powdered form). When specified, shipment is often made through Turkey. One typical example is:

“We have a success rate of 98 % at USA, Canada and European customs with Registered Mail Method only. Our company eliminates the remaining 2 % risk and gives you a customs seize guarantee. If your order is seized at the customs, we ship one more time for free. Seizured orders must be sent to a different address because customs may flag your address. And the best part is you do not have to pay the shipping charge again. We don’t have any other options of refund. We cannot resend seized orders to Australia because of extreme custom security. Orders from Australia are welcome but no one can give a %100 guarantee no matter how professional and safe packing is done”.

For obvious reasons, online retailers do not openly disclose how it is achieved but as one user said: “trust me, anyone could open the package and they would not have a clue”.

Online accounts of experimenting with ‘uncut’ DNP

The informally “recommended” dosage ranges between 200 and 600 mg, often recommending that new users start at a lower dosage and increase it gradually if tolerated well. For comparison, 100 mg equates to 1.4 mg/kg for healthy average male (70 kg); 1.7 mg/kg for healthy average female (58 kg); 1.2 mg/kg for average bodybuilder male (81.5 kg); 1.6 mg/kg for average bodybuilder female (63.5 kg), based on ideal weight for the average height, with ideal weight adjusted for bodybuilding [55, 56]. Health warnings are associated with a single dose (i.e., it should not exceed 300–600 mg at any one time) and duration of the DNP regime. The latter varies between recommended cycles (i.e., 8 days on-8 days off; 7–10 day cycle; 2 weeks on–2 weeks off; 20 or 30-day cycle, with shorter cycles tending to be recommended with higher doses) and total duration (i.e., do not exceed 20 days). According to some accounts, other substances with similar effects such as Clenbuterol (a bronchodilator with fat burning properties) are sometimes also taken in combination with, or in between, ‘on’ periods. Taking antihistamines (e.g., Benadryl or other allergy medications, quercetin extract) to manage allergic reaction is suggested, along with vitamins and stimulants such as caffeine. Kratom, a plant with stimulating effect at low to moderate dose [57], which makes monotonous hard physical work more bearable, is also gaining popularity among DNP user bodybuilders; and it has been speculated that it could counterbalance the lethargy caused by DNP. Other substances discussed for use alongside DNP include appetite suppressants, thyroxine (T3) and insulin-with mixed views and explanations.

Most concerning is that in the absence of easily accessible information and a universal safe zone for dose and exposure duration, this individual, personal-experience based advice for length and pattern for the ‘treatment’ regime is highly concerning for the public. None of these information sources draw people’s attention to the fact that DNP’s harmful effects are highly dependent on the individual’s tolerance. The only recommendation is to start at a lower (200 mg per day) dose and increase if tolerated well. Based on the available scientific evidence, even this lower dose can be harmful for some [26].

Critically important from the public health point of view are the patterns of use by bodybuilders and extreme dieters-as recorded on Internet blogs and forums - which provide an overwhelming body of evidence that dedicated users take the ‘uncut’ compound (in tablet or crystal form). Thus, the issue is not only that DNP might be sold in disguise; nor is the contamination with DNP and the trace amounts that regulatory bodies need to be worried about, but the easy access to the pure compound. The potential consequence of this is that pure DNP may not only be purchased and consumed by the dedicated and highly experienced bodybuilders who are well-prepared, but it is just as readily available to the naive users who lack experience in taking risky substances.

Several postings were concerned with the legality of obtaining DNP. These discussion threads tend to be initiated by someone interested in using DNP as part of their information gathering. Responses to such inquiries depend on the country where the responding expert user resides. Users are cautious about new brands and seek reassurance for the quality and effectives from other users.

Most notably, a plethora of postings exhibit remarkable in-depth knowledge of biochemistry which manifests in postings explaining the mechanism of DNP to novice users as well as in postings discussing synergistic effects between DNP and other substances. Reference to scientific literature is not uncommon but these postings tend to come from the same members who are most likely with relevant educational background. Experienced forum participants make efforts to provide detailed and informative answers, and take pride in their responsible and considerate approach. Disapproval of DNP use is not uncommon suggesting that although DNP use is prevalent among bodybuilders and avid exercisers, it is not a universally accepted and approved practice. In fact, those contemplating DNP use and seeking information on how to use DNP are often vetted for dietary habits, exercise regime and previous experience in controlled weight-loss and maintenance before advice on DNP is offered. In this tightly-knit, self-regulating community, novices who take this substantial, knowledge- and experience-based but impartial advice lightly or discard the warnings are often scolded for their cavalier attitude and brassiness. Questions that show absolute lack of investment into acquiring knowledge (e.g., “is DNP safe?”) or effort in weight management through diet and exercise are not well received and rebutted with a quick judgement that the person is “not ready” for DNP.

Discussion forum members sharing their experiences with DNP appear to be well-informed about the different forms such as tablets, crystal (sodium dinitrophenolate); or industrial grade powder; and their strength. These users are confident and appear to be highly experienced in using a cocktail of performance enhancing substances and are accustomed to dealing with (temporary but often harsh) adverse effects. Although accounts of death in this experienced community appear in the Internet postings, the fact that the majority of users survived and are often satisfied with the outcome of their DNP regime gives the impression to the public that DNP may not be as dangerous as the scientific literature and official standpoints indicate. However, the fact that these experienced users have managed to use DNP “safely” (that is, using DNP without death or apparent indication for long-term health consequences) does not necessarily translate to “safe use” for others, particularly among drug-naive users or those with minimum experience. On the contrary, it creates an illusory sense of safety which - coupled with a potential lack of knowledge about the strengths of different forms and the complete lack of regulatory control over these substances and labels - indeed poses grave danger to the general public. Furthermore, owing to the lack of established level of toxicity, a dose well-tolerated by one user is not applicable to another.

Owing to DNP use being a rather clandestine activity (i.e., difficult to find DNP users in ‘real life’ settings), researchers use discussion boards to recruit study participants, the present study included. Another recent example appeared briefly in March 2015 on one discussion forum, comprised of a brief “survey” aiming to explore body temperature related personal experiences in support for research investigating the potential therapeutic effect of DNP in treating hypothermia. The survey lasted less than 5 hours before the discussion thread was locked by the moderator and thus only generated a limited number of, but intriguing, responses. Forum members’ responses exhibited a great degree of suspicion, as well as support for research and remarkable knowledge about DNP. The extreme difficulty of finding people who have tried DNP - particularly in real life settings - and willing to admit DNP use was openly acknowledged.

Study 2: Screening results for DNP in bodybuilding supplements

A total of 98 samples were collected as follows: 77 were purchased in high street stores across the South of England, 16 were purchased online and five samples were donated through a local gym (of which two originally obtained from Internet, two from high street retailers and one from a gym). All five participants who donated a sample through the gym identified sustained weight management as the goal, with both being part of a fitness regime and as a quick start to the desired weight loss also appearing in two of the seven cases. Information sources were wide-ranging but notably only one person mentioned healthcare professionals (among other sources). The analysis found two of the six samples positive for DNP. Both were reported as purchased from UK Internet sites. Although side effects were reported (shaky feeling, anxiety and heart racing), these were not for the samples that were found with DNP. All participants expressed a high level of concern about DNP.

Of all samples, 14 were found positive for trace amounts (<100 mcg/kg) of DNP (Fig. 3). In contrast to high street retailers, a concerning proportion of the Internet samples were contaminated with DNP. Because DNP was detected using semi-quantitative methods (for details, see Additional file 1: DNP method development for semi-quantitative screening), the results did not afford comparisons of the concentration between different retail options; nor was it practically meaningful owing to all DNP levels being detected as trace amounts. Further interpretation of the results would warrant a study using a larger sample size and a fully validated quantitative method.

Fig. 3 Proportion of samples contaminated with DNP obtained from high street and online retailers Full size image

Positive cases were reported to the Food Standards Agency through official channels. The low concentration of DNP suggests contamination owing to poor quality control rather than deliberate adulteration (‘spiking’) to increase effectiveness. However, the fact that DNP contamination in these supplements could occur in the first place suggests that the actors of this market chain (i.e., manufacturers or distributors) of the contaminated supplement were also in contact with DNP.

Study 3: Personal experiences with DNP among users

The majority of the participants reported that they exercise three times (n = 16) or more (n = 15) a week. The remaining minority (n = 4) do not exercise or exercise only once per week. Seventeen participants use commercial gyms that are part of a chain, nine visits bodybuilding focused gyms and seven identified the gym they use as sport focused (2 responses were missing). DNP users’ profiles are summarised in Table 1. Seven of the participants (one female and six males) reported a desire to gain weight; two males with current use of fat burners. As expected, no participants in this sample wanted to increase body fat percentage. It is notable that despite the considerable variations in the current body fat percentage, males in all three age groups aim for an average body fat around 9-10 % (range = 6–15 %). Means and standard deviations for each group are displayed in Table 1. Themes emerging from the accounts of DNP users’ experiences are quantified in Table 2. Different sample sizes are due to missing responses.

Table 1 Participants body mass index (BMI) and body fat profiles by age groupsa Full size table

Table 2 Summary of users’ qualitative responses for reasons, expectations, experiences and steps taken to ensure quality of the product, presented in decreasing order of frequency Full size table

Reasons

Reasons by which participants retrospectively justified using DNP were dominantly related to a desire for an effective weight-loss strategy - either as an end-goal or as means to an end-goal, as exemplified by reasons identified as: “Just looking to drop some fat quickly”, “to be able to accomplish my goal in 2–3 weeks” and “the opportunity cost of time and the realization the DNP can shrink my cutting time by 2/3”. Curiosity (“to verify the hype”) and image enhancement (“recomp[osition]” and “improve image, and tone up”) were also mentioned more than once.

A smaller, but not insignificant group, rationalised DNP use as a feasible option after trying for other ways to manage weights. One participant said:

“I have lost over 60lbs in the past 24 months, yet still have some very stubborn fatty areas. No matter the level of cardio or calorie intake I cannot shift this fat. … DNP can literally and effectively burn fat from your body in a limited time period. As you can imagine this appealed to me.” (23 year old male)

Another participant reasoned:

“At 45 when I eat less my metabolism slows to compensate. I have to starve myself now to lose fat. Fasting and low carb dieting together resulted in a lot of muscle loss with any fat loss. My body seems programmed to preserve fat! DNP allows me to lose weight on a mild diet that my body would otherwise just adapt to by reducing metabolism and increasing catabolism. I am able to keep my metabolism at 100 % or above while eating less resulting in muscle sparing fat loss. This has been of great benefit to my overall long term health, despite the mild side effects during my DNP cycle.” (45 year old male)

Both of these users experienced that diet and exercise alone did not yield the desired fat loss and thus perceived a need for chemical help. Despite that DNP is often classed with other diet pills as shortcut that replaces hard work, exercise and diet [58, 59], only one participant justified DNP use as a shortcut: “to lose weight the easy way, can be very lazy sometimes”.

Interestingly, one of the two female DNP users rationalised DNP use as a countermeasure for the calorie intake. She said that using DNP would allow increased calorie intake without consequences on weight: “wanted to slightly increase the amount of calories I consumed while still losing weight”. Such use of DNP is akin to the use of diet pills by those with eating disorders as a compensatory behaviour [60–62]; and also noted as a contributor to Eloise Parry’s DNP-overdose [63].

DNP use patterns and experiences

The quantitative results showed that the majority of DNP users (n = 25) have had previous experience with illegal supplements other than DNP. Thirty-one DNP users reported concomitant supplement use. The type of gym they visit and past experience with illegal supplements (χ 2(2) = 1.188, p = 0.595, w = 0.182) or concomitant supplement use were unrelated (χ 2(2) = 1.196, p = 0.405, w = 0.307). Half of the sample (n = 18) reported current use of fat burners with type of gym being unrelated (χ 2(2) = 2.868; p = 2.77, w = 0.311).

For most respondents, DNP fulfilled the expectations without notable side effects. Such positive experience is exemplified by the following quotes: “lost approx 1 lb of fat per day”, “I cut 35lbs of fat within a month” and “rate of fat loss and sweating were exactly as reported, even better didn’t die luckily”. Others had mixed feelings about DNP. One 23-year-old male exerciser who used DNP for image improvement said the DNP “did the job but [with] horrible side effect like headaches”. Another user noted but immediately mitigated an unwelcome effect on diet: “cravings were unbearable so diet suffered but didn’t gain any fat” (28 year old male). Many others reported a degree of reality adjustment between expectations and experiences: “Had plenty of weight loss- wasn’t as easy as I had hoped” and “the weight loss is easier, but not as easy as some claim”, or even “less weight loss than expected”. The self-reported symptoms were irregular heartbeat, nausea, vomiting, agitation and insomnia, which are in line with those reported in the literature [12, 13].

A few participants said that the side effects were less taxing than what they were prepared for: “side effects seem largely overstated” and “I did not get as hot or sweaty as I expected, but this may be because it is winter and relatively cool everywhere”. One participant explained:

“… for me 125 mg/day was enough to lose 1 lb of fat/day. Most of the day I didn’t notice the side effects. At night or in a hot room it was uncomfortable due to the sweating and heat but normally I would not notice the side effects” (33 year old male)

Accounts downplaying the side effects - if made on open Internet forums - may inadvertently underplay the harshness and potential danger of the drug. In reality, toxic effects vary widely between individuals and thus positive cases cannot provide reassurance, or guarantee, for others having an easy DNP course. Among users it was notable that despite the negative experiences with side-effects (e.g., “[DNP] caused allergic reaction” and “DNP made it hard to catch my breath or more specifically it was harder to expel CO 2 ”), all but two male DNP users would consider using the substance again. Both participants who said that they would not use DNP again were identified curiosity (“see if it works”) as the main reason for using DNP in a first place and perhaps saw DNP as one alternative to the desired weight-loss. Even if both said they wanted to lose weight and they were satisfied or to some degree satisfied with the results, they expressed no intention to use DNP again. In the small subsample of those who highlighted negative side effects without being specifically prompted (n = 5), there was no clearly observable pattern between the forms or sources of DNP but apparently affected their satisfaction with the drug (all reported that they were somewhat satisfied with the results). Notably, 48.6 % of the sample (n = 17) felt that their expectations about DNP were fulfilled with the remaining 51.4 % (n = 18) reporting fulfilment to some degree. This relatively positive view, along with qualitative evidence suggest that users were knowledgeable about the drug and its desirable and undesirable effects and were prepared for dealing with the unpleasant side effects. As one participant summarised:

“I had fully researched DNP side effects, including death. I expected extreme heat and sweating, lethargy, headaches, staining of bodily fluids and skin (yellow). I expected to lose 1 lb per day.” (23 year old male)

Negative experiences were equally related to effectiveness as a weight loss agent and harsh side effects.

Access to DNP

The anonymous Internet purchase was the dominant method of obtaining this unlicensed drug (n = 26), of which only one was through the “dark web”, SR2. In only 6 cases users reported that the DNP was obtained from a fellow bodybuilder and only one each identified ‘dealers’ and ‘shop’ as the source for obtaining DNP. Almost all of those who identified the Internet as a source for DNP checked out the reviews about the retailer before (e.g., “used a very trusted internet source”) or made purchase based on recommendation (e.g., “[DNP] was from well recommended source”).

Reputation appeared to be an important feature for ensuring trust in the quality and relative safety of the substance, expresses as the “great reputation of the guy” or “reputation: reviews from others on internet forums”. DNP users’ responses suggest that they tend to rely on customer reviews (e.g., “I ensured that I got it from a reputable source with lots of good reviews”) and word-of-mouth (e.g., “[DNP] was from well recommended source”) when purchasing from a website. When buying from a seller, as opposed to an impersonal online retail site, personal past experience (e.g., “I trusted the supplier” and “trusted source on other matters”) was the most often cited way of ensuring that the product was genuine. Among the responses DNP users offered, there was some indication that suppliers of DNP are also users, which has helped to build reputation and ensure trust in them and in their products (e.g., “I had the same symptoms as a previous dealer I went through”).

Despite the regulation that DNP cannot be sold for human consumption, in most cases, DNP was in capsules (n = 26), with some purchased in tablet form (n = 3). This is consistent with the results from the Internet search which showed the DNP sold in online shops is typically in 100 mg or 200 mg capsules. Only in 6 cases DNP was purchased in powder form, which is how DNP is typically used for industrial applications. No association was found between the form and source (χ 2(8) = 13.176, p = 0.094, w = 0.615).

Concerns and risk management

All 35 users in our sample knew the health risks associated with DNP intake and made an informed choice. Characteristically for the sample, DNP users were not only aware of, but were also prepared for or even took pro-active steps to manage the expected side effects. Participants typically said that “I was on top of water and electrolytes” and “[I expected to] feel ill, heat, dehydration. I planned ahead for all foreseeable side effects.”

The level of concern about the quality of the DNP varied widely among the DNP users. The concern about DNP in this context refers to whether the substance purchased ‘underground’ was of high quality, unadulterated and pure. Some participants tested or get the substance tested before use. One respondent, who later stated that he did not use DNP after all, said: “I ran it through an HPLC and compared to Sigma-Aldrich 99.9 % DNP”, whereas others sent the DNP off for laboratory testing: “I used WEDINOS substance testing service (Welsh health board run service) which confirmed DNP” and “third party testing”. (Note: to date, WEDINOS [http://www.wedinos.org] has recorded 4 samples with DNP as major ingredient in powder, pill, crystal and capsule format with one each, all submitted in 2014).

Half of the sample, however, relied on reputation of the seller/retail (“ensured that I got it from a reputable source with lots of good reviews”). Others physically examined the DNP capsules or pills: “Looked for the characteristic side effects and opened a cap, saw yellow crystals”. Using one’s own body to test was not uncommon. A quarter of the participants reported some form of self-experimentation for testing DNP (e.g., “after taking a few doses the side effects matched up exactly, and there isn’t much else that gives those specific sides” and “[I relied on] reputation, plus I had the same symptoms as a previous dealer I went through.”). As one DNP user explained: “I opened that capsules and looked at the crystals. I took the pills and started feeling the side effects. There was nothing else I could do to ensure the quality, but it was bought from the most reputable seller at the time.” Only four users said that they took no action at all to ensure that DNP was genuine.

Attitudes

Attitudes toward DNP use and users were quantitatively measured with five statements (Fig. 4). Cumulatively, the attitudes which users hold about DNP suggest that DNP use is considered a sign of being committed and risks with DNP are seen as ineffective “scare tactics”. The strongest agreement (4.77 ± 1.46 on a 6-point scale where scores 4, 5 and 6 indicate a degree of agreement) was recorded for getting help with advice and medical supervision instead of scare tactics.

Fig. 4 Users’ attitudes toward DNP and prototype perceptions of DNP users Full size image

Qualitative responses provided overwhelming support for the explicitly expressed demand for accurate and impartial information on DNP. As one participant (31 year old male) said: “there really isn’t much out there for DNP aside from 1930s studies, anecdotal stories, and ‘bro science’”, identifying the Internet forums as main information source.

“There’s a lot of information on DNP on forums, however if there were more information about how to use DNP would be much better on respectable sites. All academic paper speak badly about DNP and how it’s a pesticide but it has more uses as a fat burner.” (22 year old male)

Notably, in those who ask for more information, the danger of DNP is clearly acknowledged and not the drug but users are blamed for detrimental health consequences:

“DNP is not right for everybody, but it was and is the best diet aid I’ve ever used. Proper understanding of the effects of DNP is necessary for the proper application of it. Any tool can be a weapon of self-destruction in the hands of a fool. Don’t outlaw tools just because fools will misuse them. DNP is already hard enough to get for those who are benefitted by it. I feel DNP is a far superior solution to surgical intervention for those who have difficulty losing weight or have devastating metabolic syndromes that modern medicine fails to allow DNP to be used to treat. A quick drop of 50 pounds would do your average diabetic person a world of good! DNP is a relatively effective non-invasive tool to do that. Don’t throw the baby out with the bath water! Far more people have died from obesity and metabolic related syndromes or had decreased quality and length of life than will ever be lost to DNP abuse. DNP has the power to do so much good in the hands of caring health practitioners and educated citizens.” (45 year old male)

Another participant explained:

“DNP with the right education and supplementation is fine! However, people are stupid. If you can die from something, people WILL die from something. DNP is no exception. However to the educated people who research, DNP is an effective supplement.” (31 year old male)

Media reports on DNP-related death cases appear to support this argument showing that many DNP deaths were caused by reckless use or incidental overdose; either by young individuals who suffer from some form of eating disorder or inexperienced users [63–66]. One of the most recent examples is the tragic death of Eloise Parry who apparently took eight diet pills containing DNP [63]. Following this incident, in connection with its Operation Pangea [http://www.interpol.int/Crime-areas/Pharmaceutical-crime/Operations/Operation-Pangea] - investigation targeting online sales of pharmaceutical substances - and in collaboration with the World Anti-Doping Agency, the Interpol issued an Orange Notice warning about DNP as a potentially lethal diet aid [http://www.interpol.int/News-and-media/News/2015/N2015-050]. However, users’ views on DNP show a stark difference to the official stand. As one 22 year old male said:

“DNP, in itself is a fantastic drug… There is nothing that can even come close to the results. Now granted it is a dangerous drug. It’s extremely easy to OD [overdose] on the shit and there’s no reversal. That typically scares people, which is why the FDA banned it. Human analogy suggests that if something works, take more. That isn’t the case with DNP.”

DNP was considered as a very potent and useful drug by many users in this sample: “DNP is highly effective and low doses work the best while avoiding highly-oxidative and side-effect inducing problems.” (23 year old male). The danger in overdosing and from the side effects was readily acknowledged but also counter-argued that “Any drug is dangerous if misused, info on the right dosage would be beneficial”.

Reference to alcohol and tobacco - the two substances typically used as baselines for any supportive argument for relaxed drug regulation - also appeared in the supportive argument for DNP:

“I believe this chemical is dangerous but with proper precaution the side effect and danger is worth the risk. I do not consider it any more dangerous than alcohol or cigarettes. I believe medical authorities should research this as a partial cure for obesity. Under the supervision of a medical professional I believe this could improve the quality of life of millions.” (33 year old male)

Some participants exhibited a nonchalant attitude toward one’s own body, health and wellbeing. More than one participant risked health consequences from DNP simply for satisfying curiosity (e.g., “want to see what it did, I was on it for a week only” and “to see if it actually worked that good”).

One participant, who paradoxically expressed very high level of concern about DNP but had previous experience with illegal supplements, said: “[I expected] moderate fat loss, bloating, a lot of sweating, possibly falling over and dying but meh…”. Another participant, who expressed no concern about DNP stated on the question how it was ensured that the DNP purchased was genuine: “test[ed] it in my body and see what happens”. Others were more cautious and thoroughly researched DNP before they decided to try it. For example, a 22 year old male said: “To be honest I was rather scared, once I did a little 10 day cycle I was comfortable with it. I’m on my third cycle right now. Started at 261lbs. Take all the supplements and don’t be an overzealous fat retard and you’ll do fine on DNP.” Another participant, 45 years old male, said: “I did a lot of research, exercised a lot of caution, and have had a life benefitting experience with DNP. My research led me to see that most who died from DNP had either eating disorders or a lack of self control/and poor judgement. Death is hardly the norm.” In both responses, the prevailing belief among DNP users manifests, namely that those who were in serious trouble with or died because of DNP either made a mistake (considered as an avoidable factor) or suffered from an eating disorder (considered as a non-relevant feature).

Normative perceptions

On average, DNP users estimated that a quarter of bodybuilders (23.05 ± 20.00 %) use DNP. Detailed normative perceptions by user details (current use of fat-burner and having experience with other illegal supplements) are depicted in Fig. 5. The difference between current fat-burner users and non-users was small and non-significant (t(16) = 0.059, p = 0.954, d = 0.029, 24.55 ± 21.96 % vs. 25.14 ± 19.25 % for current users (n = 11) and non-users (n = 7) respectively). The small effect size suggests that current behaviour with similar drugs does not influence the estimation regarding DNP. Equally, there was an observed but statistically not significant difference in estimations (t(18) = 0.730, p = 0.478, d = 0.379) made by those who only used DNP (n = 6; mean estimation = 18.00 ± 15.94 %) from the array of ‘illegal supplements’ versus those with more experience (n = 14; mean estimation = 25.20 ± 21.68 %). From literature precedence, it was expected that the perceived legality of the drug - possibly through mental representation of DNP - could influence the estimation of DNP use among others. In similar context, it has been observed that athletes involved in socially detested behaviour (e.g., doping) tend to overestimate the same behaviour among others compared to those who are absent, but with no difference in estimations of the use of performance enhancing aids such as nutritional supplements that can be used without restrictions [67–69]. In the present sample, the observed difference (18 % vs. 25 %) lacks statistical support for the legality effect on projected use; and thus may only reflect random variation in the sample. Future research specifically tailored to investigate projection bias is needed to ascertain if the difference manifests in subsequent studies with robust evidence for statistical significance.

Fig. 5 Comparison of the perceived normative estimation of DNP use among bodybuilders and avid exercisers based on (a) whether fat-burner substance is used at the time of data collection and (b) having experience with other illegal supplements Full size image

DNP represents a grey area on multiple accounts. Technically, DNP is not an illegal drug to take, but it is not licensed for human consumption, thus selling for such purpose is illegal. From the cognitive point of view, it is an interesting case because DNP may very well be perceived as illegal owing to the clandestine nature of purchase and use, even if from the legislative point of view, there is nothing illegal about buying and using DNP. A similar phenomenon has been observed regarding performance enhancing nutritional supplements among athletes [70]. Thus we expected that those using other illegal substances may automatically class DNP as illegal whereas those who do not use anything illegal had a more accurate view. Perhaps it is because legality is important to these users, not wanting to cross the border between legal and illegal; whereas those with experience with illegal supplements already did so. Further research with experimental design manipulating the legality condition is needed to ascertain whether a heuristic bias regarding DNP exists (i.e., DNP users who also use other illegal bodybuilding substances may subconsciously include DNP in that category whereas those who stay away from illegal bodybuilding substances may not see DNP as illegal). The importance of this aspect lies in the potential effect on prevention strategies and communication.

Contrast between the Internet and real life

Break-down of the estimations by the type of gym (Fig. 6a) shows an interesting - and intuitively unexpected -pattern. DNP users attending leisure/exercise-focused ‘chain’ gyms give much higher estimation for DNP use among others (28.45 ± 23.09, n = 11) than those attending sport- or bodybuilding focused gyms (13.75 ± 17.50; n = 4 and 15.75 ± 11.79; n = 4), respectively). Although the difference in projected estimations did not reach statistical significance, the effect size suggests that the lack of statistical significance is the function of the interplay between the small sample and large variance (F(2,19) = 1.053; p = 0.372; η 2 = 0.116), resulting in the test being underpowered to reject the null hypothesis when the difference between the three groups may exist. Further research with adequately powered statistical test is warranted.

Fig. 6 Comparison of (a) the perceived normative estimation of DNP use among bodybuilders and avid exercisers and (b) visibility of DNP use by the type of gym used in the sample Full size image

On the contrary, the visibility of DNP use through the reported known proportion of DNP users (Fig. 6b) shows the opposite pattern, with the highest proportion reported by people attending bodybuilding focused gyms (0.262 ± 0.375 vs. 0.215 ± 0.440 vs. 0.162 ± 0.320, respectively for bodybuilding (n = 6), sport (n = 5) and leisure/exercise-focused (n = 10) gyms). The difference was not statistically significant and the effect size was small (F(2,18) = 0.144, p = 0.867, η 2 = 0.016). The reported proportion of known DNP users was surprisingly low across the sample. Against the average number of bodybuilders personally known by the sample (11.38 ± 14.50), and the estimated normative prevalence at 23 %, the known number of DNP users among them (1.12 ± 2.05) barely reaches 10 %. The average number of DNP users expected from the projected prevalence (2.63 ± 4.07) significantly exceeded the average number (1.24 ± 2.46) of reported known users (Wilcoxon Z = −2.274, two-tailed exact p = 0.021, point probability p = 0.002), with a significant positive correlation between the reported and estimated DNP user numbers (Spearman r(18) = 0.665, p = 0.003).

Taken together, these results suggest that DNP practices and experiences are shared online, but not in real life. DNP use appears to take place in isolation. This may partly so because of the social disapproval of DNP use, even among bodybuilders; but also because managing the side effects (profuse sweating, skin discoloration, etc.) in public is difficult. In fact, new users are advised in discussion forums to start the cycle when on holiday if they are in employment. Conceivably, sharing experiences online is a way to deal with isolation and loneliness during a DNP course. If this is the case, online forums play an important role beyond being a compendium of DNP knowledge; and it warrants further investigation.

During data collection we encountered numerous cases where people, who willingly shared their experiences with DNP and readily offered information and advice to other forum users, were initially suspicious of a newcomer asking questions about DNP and were not very willing to participate until the investigator gained trust and became accepted in this unique group. Perhaps DNP in a sporting context, owing to its high risk and harsh side effects, is similar to harsh drugs among substance users, where people are much more ready to admit using a relatively harmless substance (e.g., smoking marijuana) than confessing a more stigmatising “hard drug” use (e.g., snorting cocaine or injecting heroin). Whilst the stigma attached to psychoactive drugs has two facets (addiction and criminalisation), for DNP, it is conceivable that such distinction is mainly driven by the degree of health risk and rather than legal consequences.

The high estimating of use by leisure/exercise gym users (which is likely to be an over-estimation at 28 %) is concerning on two counts. First, against the relatively low reported number of deaths from DNP, it can create a false sense of security by believing that DNP use is a common and safe practice. Secondly, this group is likely to be the most naive and least experienced when it comes to using “hard” sport drugs (e.g., anabolic steroids, hormones, other fat-burners such as Clenbuterol), dosing properly and managing adverse side effects. As one ex-professional powerlifter (a 22 year old male) offered for explanation: “Some bodybuilders may use other drugs to the same effect- clen [clenbuterol] is especially popular, that is why my estimate for DNP use is so low”. Another participant, a 23 year old male, linked DNP use to anabolic steroids: “Typically DNP users are mostly bodybuilders that are already on anabolics. I was not on anabolics and I have never taken them so my results may not have been as good as others on online forums.”. Because we did not ask the participants to reveal full details of their supplement and substance use, future research is required to ascertain the relationship between DNP and other, legal and illegal, substances.