The FDA says the supplements, sold under the names Actra-Rx or Yilishen, actually contain an active prescription ingredient that could cause serious complications in some men.
The agency has also issued an alert instructing FDA officials to stop the importation of Actra-Rx and Yilishen.
A chemical analysis published earlier this year in The Journal of the American Medical Association showed that a sample of Actra-Rx sold by Body Basics of Los Angeles contained a prescription-strength amount of sildenafil. Sildenafil is the active ingredient in the prescription drug Viagra, which is approved by the FDA for the treatment of erectile dysfunction.
In its own tests of Actra-Rx, the FDA also found that the supplement contained prescription-strength sildenafil.
Dangers of Sexual Supplements
FDA officials say an interaction between sildenafil and certain prescription drugs containing nitrates, such as nitroglycerin, or nitrates found in illegal drugs may cause a dangerous lowering of blood pressure.
People with high blood pressure or heart disease are often prescribed drugs containing nitrates. Because erectile dysfunction is a common problem among men with these conditions, officials say taking Actra-Rx or Yilishen could increase the risk of serious and potentially life-threatening side effects.