What Are Prohormones?
What Are Prohormones?

Prohormones remained largely unknown to the general public until 1998, when a reporter spotted androstenedione in the locker of home-run slugger Mark McGwire. Suddenly, young athletes everywhere were desperate for this new wonder supplement. The fact that McGwire broke Roger Maris’ record of most home runs in a single season that year sent sales through the roof.

In some respects, prohormones are a direct result of the reclassification of anabolic steroids as illegal substances back in 1990. Recognizing that many former steroid users would be looking for a legal alternative supplement, manufacturers began hiring biochemists to synthesize a new class of supplements that possessed steroid-like effects without side effects or legal issues. Thus, the prohormone was born. While the effectiveness and safety of prohormones has been debated since their first use in bodybuilding, there is no argument about their current status – they are illegal! In 2004 the Anabolic Control Act was amended to include prohormones as illegal substances. Essentially, this act means that possession of either steroids or prohormones could land you some serious jail time. It’s not worth the risk of using prohormones. Still tempted? Well, look at it this way – where would you rather pump iron? The local gym or the prison courtyard?

Breaking It Down

For those not familiar with prohormones and the terms commonly used to describe them, let’s begin with a brief overview. Using androstenedione as an example, we see that it is a molecule very similar to testosterone, the principal male sex hormone. The primary difference is that where testosterone has a hydroxyl group (hydrogen and oxygen bonded together and written as –OH) in a specific position, androstenedione has a keto group (carbon and oxygen bonded by a double bond; C=O). Simply put, androstenedione is one step away from testosterone. This makes it a “precursor” or a “pro” (coming before) hormone.

The body can convert androstenedione to testosterone (and vice versa) by use of a specific enzyme that is present in the body in fairly large amounts. Oral androstenedione supplementation very briefly increases blood levels of testosterone. It is this ability to act as a direct hormonal predecessor of testosterone that makes it attractive to bodybuilders and other athletes. But while androstenedione is a precursor of testosterone it is also, unfortunately, a precursor of estrone, one of the estrogenic hormones. As such, it can have adverse estrogenic effects similar to those of anabolic steroids, such as gynecomastia (feminized swelling of the nipples). Also, testosterone not only converts to estrone, but to a potent androgenic compound known as dihydrotestosterone (DHT). Increased DHT levels will sometimes lead to hair and skin problems.

Other Variations

Other variations of androstenedione are available including 4-androstendiol (4-AD) and 5- androstenediol (5-AD), which differ chemically by the position of the chemical double bond in the steroid molecule (hence the “4” and “5” designations). Like androstenedione, they also have both androgenic and estrogenic activity (but in the case of 4-androstendiol, the estrogenic conversion is indirect).

Another group of prohormones called “norandro” products are precursors of a compound called nortestosterone, also called nandrolone. Nandrolone is a sex hormone found in certain animals including horses. It also makes up half of the popular anabolic steroid nandrolone deconate (also known as deca-durabolin).

Nandrolone exhibits a higher anabolic (tissue-building) activity in humans in relation to its androgenic activity than does testosterone. Since nandrolone metabolizes to a weaker compound than testosterone does, called dihydro nandrolone, precursors of nandrolone are much less likely than testosterone to cause hair, skin, and other androgenic problems. Available variations are 19-nor-4-androstenedione (19-nordione), 19-nor-4-androstenediol and 19-nor-5- androstenediol (19-nordiols) (once again the numbers indicating the relative positions of the primary bonds in the molecule).


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