A reader asks: Testosterone supplement ads say they increase muscle mass and improve sexual performance. Are these supplements safe? Here’s the reply from Johns Hopkins.
You have no guarantee of the safety or effectiveness of any dietary supplement, including those promoted as natural hormones. Dietary supplements are not required to undergo the rigorous testing that pharmaceutical drugs do. You also have no guarantee that a supplement contains the ingredients listed on the label or that it does not contain harmful ingredients or contaminants.
The potential dangers of these unregulated substances were underscored recently in a letter published in the Archives of Internal Medicine. In the letter, physicians from The University of Texas Southwestern Medical Center in Dallas reported that two men, ages 51 and 67, developed widely metastatic prostate cancer within months of beginning a testosterone dietary supplement that was advertised in a fitness magazine. Both men had been screened for prostate cancer within the previous 11 months and were found to have normal PSA levels and digital rectal exams at that time.
While it's not possible to draw firm conclusions that the testosterone supplement was responsible for the cancer, laboratory experiments showed that it is a potent stimulator of prostate cancer cells. In addition, it made the cells resistant to the antiandrogen therapy used to treat advanced prostate cancer.
