Athletes owe their success to a lot of things. Their drive, hunger for success, and hard work are part of it. But some of them owe their success to Adolf Butenandt, the German scientist who would be the first ever to isolate androgen (a class of steroids that includes testosterone) from a bunch of urine he got from a police barracks in Berlin in 1931. I know, science works in mysterious ways.

"Everything's glandular" to quote the mind of Noel Coward.

Indeed it is. Butenandt's research would essentially pave the way for our understanding of endocrine function in general, and steroids specifically. But why are hormones so critical to sports performance? Aren't hormones those evil demons that control your thoughts sophomore year of high school while you pine for the cute girl sitting next to you in English class? Sort of.

With the steroid discussion en vogue thanks to Georges St-Pierre being disappointed in the UFC's inability to back him on increased and more efficient drug testing, and Anderson Silva getting busted following UFC 183, I figured now would be a good time to relearn our PEDs like our ABC's.

So why hormones?

Your body's growth depends on your cell's ability to clone themselves, as well as their ability develop from immature cells into specialized cells (such as bone cells, muscle cells, nerve cells, etc.) in a process called differentiation. Steroids are sometimes used in cancer patients for this reason; because they help stimulate cell differentiation which is otherwise stripped of specialization.

Just like you, the reader, needed to swim around your dad's private parts before becoming the twitter addicted eukaryote sitting before you, so do cells that work to enable your body's many systems. And that's what makes steroids, particularly anabolic agents, so critical to traits an athlete may feel gives them an advantage.

However, hormones in general, and steroids in particular are fairly complex. So much so, it's a wonder I've been allowed to write this. For one, steroids are unlike a lot of molecules in their ability to penetrate not just cell membranes, but your very skin. Athletes like Dan Henderson, Chael Sonnen, Vitor Belfort, and a bunch of other dudes with laughable doctor's notes about needing testosterone can attest to this as testosterone itself can be used as a gel. As John Coates notes in his book The Hour Between Dog and Wolf, "furthermore, unlike other hormones, which generally have effects localized to one or two tissues, steroids have receptors in almost every nucleated cell in the body. All these properties of steroids give you an inkling of their power." In other words, there's a reason athletes chase, inject, and hoard hormones in order to be bigger, stronger, and faster instead of stealing ancient gems from comic book villains.

Anastrozole

How it works for you, the performance enhancing evildoer: It's important to remember just how powerful hormones are. Never is this more emphasized than what happens when the casual fan hears about a fighter who used drugs to treat breast cancer. Wait...why??

On the surface, it looks bizarre. Anastrozole combats and limits the amount of estrogen secretions in the body, which in turn, maximizes the effects testosterone has on the body. Which makes sense. Estrogen gives rise to female characteristics while testosterone is largely responsible for male characteristics. Allowing estrogen to run rampant in the body could yield some of the physical side effects of estrogen, such as gynecomastia. However, it's important to note that both hormones are needed which helps explain the next chemical Chael also popped dirty for for.

PED Mugshots: Chael Sonnen

Androsterone

How it works for you, the performance enhancing evildoer: Testosterone is not the only chemical that helps masculinize the fetus. Androsterone is one such chemical, doing things similar to what many steroids do. However, Androsterone is sort of unique in that it has "pheromonic" traits; where hormones can be thought of as triggers, pheromones can be thought of as releases.

A close cousin of Androsterone, Androstenone (yes this is hopelessly confusing), is famous for the dentist's chair experiment; a dentist's chair would be sprayed with androstenone, which women during ovulation would prefer compared to men, who tried to avoid it. The experiment is a minor spin on the sweaty shirt experiment I wrote about awhile back when I asked the pothead question of fighters using their sense of smell. Androstenone is so strong a pheromone that farmers use it to determine if female pigs (which identify it in the saliva of male pigs) are ready to be impregnated.

PED Mugshots: Anderson Silva

Boldenone

How it works for you, the performance enhancing evildoer: Boldenone, with pseudonyms as varied as Tyrion Lannister's infidelities according to wikipedia, is like all anabolic agents in that they attempt to replicate the tetris-like work your body does to grow.

But it also does a few more things. It ensures nitrogen retention. This is important for you, the 'cheating' athlete, because the more nitrogen you can retain, the more muscle mass you can theoretically build, since that muscle would be otherwise broken down and eliminated due to catabolic and excretory processes.

It also stimulates your kidneys. While your kidneys are important for filtering blood, they also do many other things, like synthesize vitamin D, and remove the waste that accumulates from metabolism.

PED mugshots: Josh Barnett, Stephen Bonnar, Kite Cope, Phil Baroni, Anthony Torres, Alexandre Nogueira, Antonio Silva

Clomiphene

How it works for you, the performance enhancing evildoer: It is said that football players tend to have high levels of both testosterone and estrogen. Hormones work like the laws of thermodynamics in that they can't be created nor destroyed. They're all critical despite working like geysers in the body, sometimes eruptive, sometimes dormant. But they're essential all the same. On its own Clomiphene helps the pituitary gland secrete hormones to in order to trigger ovulation. One of those chemicals important to ovulation? Estrogen, of course.

Estrogen is critical, and not just in a biologically rudimentary way. Rather, it is critical in a very biologically holistic way. Estrogen is not just the chemical of Jennifer Aniston films, and Valentine's day. It's just as much the chemical of combat as testosterone is. Consider its role maintaining bone mass, for example, by helping maintain the production of osteoblasts (bone forming cells) while osteoclasts (bone destroying cells) proliferate with age (perhaps helping explain the longevity gap between women and men, the latter of which is outnumbered by women 6 to 4 at the age of 85).

PED Mugshots: Chael Sonnen

Desoxymethyltestosterone

How it works for you, the performance enhancing evildoer: This chemical happens to be a close cousin of dihydrotestosterone, which is a derivative of testosterone and is often singled out by personality experts as the chemical of distrust, and cold logic. Desoxymethyltestosterone is pretty standard issue as far as anabolics go: muscle building, increased RBC count, and has a higher anabolic effect than testosterone by itself.

PED Mugshots: Hector Lombard

Diuretics

You know this already so I don't mean to waste your time, but it's worth noting anyway. Because urine samples are often used to "detect" the presence of doping agents, it's useful to manipulate that urine. That's what diuretics are for, which increases the rate of urine flow. This process limits the amount of water reabsorbed back into the body, which is why they're good for losing weight as well. That specific increase is what essentially dilutes the urine so that it's difficult for doping agents to be detected. I wouldn't recommend kidnapping the neighbor's Welsh Corgi for a urine ransom the way Kevin Randleman may or may not have done.

PED mugshots: Thiago Alves, Ashlee Evans-Smith

Drostanolone

How it works for you, the performance enhancing evildoer: You get the picture when it comes to anabolic agents. However, each drug has its own unique elements, and are popular for different reasons. It's important for prizefighters to lose mass while retaining strength because of weight classes.

Drostanolone is popular in particular for this reason, since dieting is supposed to lead to muscle loss, unless of course you have the right chemicals. In other words, the appeal is often considered 'cosmetic' as its ability to add mass are considered limited by comparison to other drugs.

PED mugshots: Hermes Franca, Bill Mahood, Dennis Hallman, Josh Barnett, Muhammad Lawal, Stephen Bonnar, Anderson Silva

EPO/Erythropoietin

EPO stands for a hormone secreted by your kidneys called erythropoietin - a hormone that stimulates the production of red blood cells.

Your red blood cells work like magnets in relation to the oxygen you take in; part of your RBC's contain hemoglobin, an iron molecule that binds to that oxygen. The more RBC's your body produces then, the more oxygen your body can hold. This is why it's so popular and critical in endurance sports like cycling. I ignored this one like an idiot because I presumed its lack of significance to muscle mass would make it useless, but that's obviously ridiculous (as some readers were quick to point out). Plenty of fighters rely on attrition to win fights, and in the championship bouts, this is even more critical.

Plus there's the fact that MMA testing is a joke. Governing bodies for cycling have the 'biological passport' system which uses electronic records from tests taken over time, like a longitudinal study. This is what was done with cyclist Bradley Wiggins. Doctors could measure the amount of mature red blood cells to immature red blood cells because if you have too many more mature RBC's than immature RBC's, then something is obviously up.

What they're looking at is your hematocrit levels; which is RBC volume for all intents and purposes. Basically, your blood consists of 55% plasma (mostly water), and 45% formed elements (red blood cells, white blood cells, and platelets). EPO will shift that balance, which is dangerous for the heart as it makes the blood heavier, which makes it harder to pump throughout the body.

It's useful to mention EPO in the context of gene doping. I talked about this awhile back, and it was part of my conversation with Sports Gene author David Epstein. What's interesting is that the prospect of gene doping (which WADA already bans) seems to get closer and closer to the horizon, and EPO is the target in question.

PED Mugshots: Ali Bagautinov, Chael Sonnen

Fluoxymesterone

How it works for you, the performance enhancing evildoer: The appeal of this drug is in its so called androgenic properties (testosterone is an androgen). You have different types of muscle tissue in your body; skeletal (which you can control voluntarily), smooth and cardiac (which you cannot control voluntarily as they have to do with your digestive system and heart, respectively). Androgens do their work on skeletal muscle, increasing its mass.

But they also affect lean muscle mass by lowering fat accumulation by preventing fat cells their ability to store lipids which is enabled by an epinephrine/norepinephrine increase.

What's interesting about this process is that fat cells are rich in an enzyme (aromatase) that transforms testosterone into estrogen in order to make testosterone active (read it again if you must; I don't understand biology either, I'm just a messenger). This explains why some men develop what is commonly known as"gyno", or man boobs.

PED mugshots: Josh Barnett

(4-)Hydroxytestosterone

How it works for you, the performance enhancing evildoer: It's important to note that steroids are like any other drug...there's good shit, and then there's bad shit, and sometimes you have to accept the latter because you either can't afford the former, or you don't know the difference.

I'm not an expert on drugs in general, but this particular drug appears to fall into the "bad shit" category if my research into random bodybuilding forums is any indication. As in, from many accounts it's weaker as an androgen, but the plus is that it has a short half-life and "anti-estrogenic properties".

PED mugshots: Vitor Belfort, Ruben Villareal

Marijuana

I figured I'd touch on this. Per WADA, marijuana is illegal, but the example of weed is interesting because it begs the question with respect to where the line is drawn when it comes to what constitutes 'performance enhancement'?

Some studies indicate the opposite, and I don't mean in a silly "but weed makes you the anti-drunk driver" way. I mean some preliminary studies have revealed weed to have an effect on your lutienizing hormone by lowering it (as mentioned above LH is responsible for converting specific hormones into testosterone). This is why you hear stories about weed being linked to man boobs, though like with most marijuana studies, there just aren't enough of them to approximate a conclusion.

PED "mugshots": Nick Diaz, Diego Sanchez, Keith Barry, Nick Moghaddam, Fernando Gonzalez

Nandrolone

How it works for you, the performance enhancing evildoer: Similar to Boldenone in that it promotes muscle growth, red blood cell production, but also bone density through supporting cell differentiation and mitosis.

What makes Nandrolone different (and the reason why you see so many fighters who have a PED mugshot to accompany it) is the side effects are said to be less pronounced (cosmetic and chemical). It also plays a part of the narrative that fighters need testosterone replacement therapy based on prior steroid use.

This is because nandrolone has the side effect of lowering your luteinizing hormone levels; a hormone controlled by your pituitary gland that in females prepares the egg for fertilization, and in males, allows for the conversation of other hormones into testosterone.

PED mugshots: Josh Barnett, Stephen Bonnar, Nate Marquardt, Pawel Nastula, Royce Gracie, Sean Sherk, Dennis Hallman, Carina Damm, Edwin Dewees, Joey Beltran, Adam Smith

(19-)Norandrosterone

How it works for you, the performance enhancing evildoer: It's an anabolic agent, so by this point, you know a few things, but you may not know this very unusual fact about 19-norandrosterone.

"Although highly improbable, athletes should prudently avoid meals composed of pig offal in the hours preceding the test since the consumption of edible parts of a non-castrated pig, containing 19-nortestosterone, has been shown to results in the excretion of 19-norandrosterone in the following hours."

From PubMed.

PED mugshots: Ken Shamrock

Stanozolol (Winstrol)

How it works for you, the performance enhancing evildoer: It's like all other anabolic agents; lose fat while retaining body mass, red blood cell production (which is why it can be used to treat anemia), and so forth.

Its popularity is likely explained by its so called minimal 'androgenic effects'. Androgens, like testosterone, is more or less what create male characteristics, which means no progeria, or Vin Diesal voice. Winstrol is therefore said to be popular especially among females (likely explaining why Cyborg is on this list).

Also, the chemical properties of Stanozolol are such that it is much stronger than testosterone, with the trade off being that it's also much more toxic to your liver.

PED mugshots: Tim Sylvia, Kimo Leopoldo, Phil Baroni, Chris Leben, Kirill Sidelnikov, Vinicius Quieroz, Cristiane Santos, Rafael Cavalcante, Adam Smith

Stimulants

Sometimes drugs that can be legally purchased are off limits per WADA's standards. Phentermine can be legally purchased, and it's job is similar (in principle) to Drostanolone in that it aids in weight loss (in this case by using epinephrine to break down fat), which is why it's used sparingly to treat obese patients. Adrafinil, a drug used to treat excessive sleepiness and fatigue, is also banned despite its similarities to caffeine, which is not banned (though it used to be).

One in particular worth noting is Modanifil which is a psychostimulant generally used for sleep disorders such as narcolepsy, and daytime sleepiness. However, one of Modanifil's side effects has been linked to the "dampening of the sensation of fatigue". It has been shown to increase aerobic capacity (or VO2max) like EPO on the cheap, essentially.

PED Mugshots: Rob Emerson