Androstenedione - Andro

Andro: From Dietary Supplement to Banned Steroid

A bodybuilder with a handful of pills.
A bodybuilder with a handful of pills.. Jupiterimages/Getty Images

What is Androstenedione - Andro?

Androstenedione (Andro) is the muscle-building supplement that baseball home run champion Mark McGwire made famous. But since that episode, it has been classified as an anabolic steroid and as such, it is illegal to use without a legitimate medical reason.

Also Called: 4-androstenedione or 4-androstene-3, 17-dione

What Does Androstenedione Do?

Androstenedione is made from a naturally occurring steroid hormone.

In your body, androstenedione is a prohormone produced in the adrenal glands, testes, and ovaries. The body metabolizes androstenedione into testosterone, the chief male hormone, as well as into the estrogens estrone and estradiol. When using andro as a supplement was legal, it was used in hopes of boosting testosterone levels in the body. In addition to giving both men and women male characteristics, testosterone has an anabolic effect, increasing muscle size and strength.

Therapeutic androstenedione may be used to increase plasma testosterone levels. Studies often didn't find androstenedione supplements to be effective in boosting testosterone levels. Some studies showed that the net result was to boost the estrogen level instead, and had no anabolic effect on muscles in young men. Used as a supplement, it as also seen to have bad effects in lowering HDL cholesterol, which would raise coronary heart disease risks in men.

Androstenedione Use in Sports and Bans

For years Major League Baseball did not ban andro despite evidence that its use could be hazardous to those taking it without a legitimate medical reason. It had been previously been banned by the Anti-Doping Agency, International Olympic Committee, the NCAA, the NFL and the men's and women's tennis tours.

In January of 2005, the Anabolic Steroid Control Act was amended with the Controlled Substance Act that added anabolic steroids and prohormones to the list of controlled substances. This makes possession of the substances a federal crime. In 2004, the United States Food and Drug Administration (FDA) banned the sale of Andro, because of evidence to support increased health risk when using this substance.

FDA Import Alert 54-11, dated 9/15/2015, gives guidance to districts is that any dietary supplements listing androstenedione, 4-androstenedione or 4-androstene-3, 17-dione may be detained without physical examination. Simply listing it is cause to prevent its import into the United States.

Side Effects of Androstenedione

The research was somewhat mixed as to whether andro supplements worked at all to raise testosterone levels, but it was shown to have negative side effects and increase health risks.

It can interact with blood thinners such as Coumadin and salicyclates. It can also interact with diabetes drugs such as sulfonylurea and insulin, decreasing blood glucose concentration.

It may lead to severe acne or edema if taken with corticosteroids.

The US FDA White Paper on the health effects of Androstenedione in 2005 cited the ill effects they feared would happen to children and adolescents who took andro long term. This included feminization of boys and virilization in girls. Premature puberty could lead to shorter stature.

Increased testosterone in older men can cause an increased risk of prostate cancer growth, as well as growth of liver cancer and breast cancer in both men and women.


National Center for Biotechnology Information. PubChem Compound Database; CID=6128, (accessed Jan. 30, 2016).

US FDA; FDA White Paper Health Effects of Androstenedione. March 11, 2004

Thomson.Micromedex. Drug Information for the Health Care Professional. 25th ed. Volume 1. Plus Updates. Content Reviewed by the United States Pharmacopeial Convention, Inc. Greenwood Village, CO. 2005., p. 142.

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