Men who use muscle-building supplements (MBSs) that contain creatine or androstenedione may have up to a 65% increased risk of developing testicular cancer, according to a case-control study published online March 31 in the British Journal of Cancer.

This risk increased even more among men who began using MBSs before age 25, who used various kinds of MBSs, or who used them for a long duration.

Muscle Tech, carried by many major vitamin suppliers, is one of the brands which lists creatine and androstenedione.

Muscle building supplements have been popularized by major gym chains and personal trainers for years as a supplement to profits and income. None of the supplements on the market today are regulated by the FDA for safety or efficacy.