The Prohormone reference article from the English Wikipedia on 24-Apr-2004
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Prohormone

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A prohormone is a chemical compound that is a precursor to an actual hormone (usually an anabolic like testosterone or some variant), which is taken in order to boost the body’s available hormone supply. These precursors typically convert to full hormones via an enzymatic process that occurs during metabolism, resulting in the addition of whichever atoms happen to be missing.

The use of prohormones has become popular among bodybuilders, since the effects can be similar to those achieved through the use of steroids, including gains in muscular strength and growth of lean muscle mass. There are currently many companies manufacturing prohormone products for this purpose.

Prohormones are legally sold in most parts of the world and are classified in the United States by the FDA as dietary supplements because they consist of compounds that are found naturally in the human body; however their use remains quite controversial and side effects are not uncommon. To date most prohormone products have not been thoroughly studied, and the health effects of prolonged use are mostly unknown.

Common types of prohormones on the market