Androstenedione is a hormone that is produced in the gonads of men, the ovaries of women, and the adrenal glands of both genders. It is produced in people before the appearance of either testosterone or estrogen. In males, androstenedione is converted to testosterone using the enzyme 17β-hydroxysteroid dehydrogenase. For females, the enzyme aromatase is used to covert this hormone into estrogen. This compound is also known as a prohormone, which is a precursor substance that leads to hormone production, but lacks many of the functional qualities of a true hormone.
The existence of this hormone was originally documented in 1935, but its function in testosterone production was not known until the early 1950s. In the 1970s, androstenedione began to be usd as a supplement by East German athletes, who would use a nasal spray of the hormone before competition. This produced a short, one to three hour boost in testosterone levels, and this was thought to aid in performance. The exact mechanics of this process were never disclosed, however.
Initially, little was known about the full effects of androstenedione, save for its ability to increase testosterone levels. It was manufactured commercially as a dietary supplement in many countries, and went by the name andro. Patrick Arnold, an American chemist, is said to have introduced this compound to the North American market. The product was available as an over the counter supplement in the United States until 2004, when the Anabolic Steroid Control Act was introduced. This legislation banned both anabolic steroids, which mimic the effect of testosterone, and prohormones. The sale of andro was officially banned by the United States Food and Drug Administration (FDA) on April 11th, 2004.
This prohormone is classified as a steroid, though some debate exists as to whether or not it should be classified as a prohormone or an anabolic steroid. It does fit the definition of a prohormone, but also closely matches the definition of an anabolic steroid, which mimics the function of testosterone. Under the Anabolic Steroid Control Act, androstenedione is classified as an anabolic steroid, but many sports trainers and Internet websites consider it a prohormone.
Androstenedione is merely a precursor to testosterone, and does not actually mimic the effects of that hormone. Instead, it leads to the true production of it. Regardless of its classification, however, this substance does lead to several of the same side effects as anabolic steroids, including elevated blood pressure, increased risk of cardiovascular disease, and liver damage.