The U.S. Anti-Doping Agency last week announced that some athletes have been using the drug -- technically known as tetrahydrogestrinone -- to enhance athletic performance.
"Our mission is to protect the American public from this potentially harmful product," John Taylor, FDA associate commissioner for regulatory affairs, said in a news release.
The FDA warns that THG, sold as a supplement, is actually an unapproved new drug. As such, it cannot be marketed without FDA approval. No such approval has been granted.
The FDA announced that it will aggressively prosecute firms or individuals who manufacture, distribute, or market THG.
Little is known about how THG actually works. However, it is similar to other anabolic steroids that can pose considerable health risks.
Side effects associated with regular steroid use by males include reduced sperm production, shrinking of testicles, impotence, baldness, and breast enlargement. Their use has also been linked to an increased risk of liver cancer and cysts, increased cholesterol, high blood pressure, and heart disease.
Steroids are also associated with increased anxiety and aggression. Teens who take them risk stunting their growth.