What is a Prohormone?
Prohormones in the broadest sense is anything with a hormonal action that converts into something else that is presumably active. All hormones are really prohormones to something else, because the amount of interconversion between hormonal agents is nearly endless. When a steroid is relatively weak on it’s own or has no activity it is called a “pro hormone” when an androgen is active on its own it is typically called anabolic steroids. This is what separates a prohormone from an “anabolic steroid”.
If you are new to prohormones you can read this Andro FAQ or read our article on the Best Prohormones.
Prohormones in modern times (post 1994) have meant androgenic steroid precursors that convert into active androgens like testosterone and other steroids. Prosteroids are active androgens that work on their own without conversion, so for example testosterone and 1-testosterone are active androgens where androstenedione and 1-andro would be their prohormones. Prosteroids are simply active steroids. but unfortunately steroids are typically illegal due to chemical modifications. These steroids like M-Drol, Superdrol and other similar agents are active androgens that require no conversion. Also there can be synthetic steroids like H-Drol that require enzyme activation yet are chemically modified.
The conversion of a prohormone to an active steroid requires enzymes in the body. This limitation is what allows the prohormone to have a rate limiting mechanism, thus increasing the safety profile. The two main enzymes that convert a prohormone to an active steroid are 3b-hydroxysteroid-dehydrogenase and 17b-hydroxysteroid-dehydrogenase. These enzymes act on the 3 carbon position or the 17 carbon position to make the steroid active as in this diagram. As you can see at the bottom, the two enzymes 17bHSD and 3bHSD are responsible for converting androstendione and androstenediol into testosterone. All of the structures shown on the chart are steroids, which shows you the broad nature of the term “steroid” which includes cholesterol and Vitamin D.
Changing the position of the double bond also changes the activity of the prohormone as well as what enzymes can act on it. Testosterone is a “4-ene” steroid, meaning it has a double bond at the 4 position as shown here.
Derivatives such as 1-Testosterone shown below stop some enzymes like the conversion of estrogen via aromatase in the above example. If you were to replace 1-Testosterone with testosterone in the body, you would not have any estrogen.
Contrary to what you think you need all of your steroid hormones, including cortisol, estrogen, progesterone and dehydro-testosterone to live. When steroid hormones get out of balance though, you may not feel optimal. For example environmental toxins like BPA and Parabens reduce the ability of the body to make testosterone and also act like estrogen in the body, which can cause men to feel the effects of low testosterone. Additionally, other environmental estrogens like pesticides can throw off the Estrogen to Androgen ratio which would make you appear “healthy” on a blood test, but change the ratio of estrogenic to androgenic agents in the body. This bombardment of estrogenic agents in the diet and in environmental waste products makes it important for men above 21 to supplement with androgen prohormones to look and feel their best. With proper androgen prohormones it is possible to reclaim our masculinity and reverse the damaging effects of estrogen, which are increased fat deposits, loss of sex drive, lost feelings of well being and depressed moods.