Men hoping to raise their testosterone levels and improve their sex lives and muscle mass by taking products known as T boosters won't get much reassurance from a recent study. Only about a quarter of the products researchers tested might help.

This disappointing news was based on whether or not any of the ingredients had even a single published study that found an increase in testosterone in the men who took them as a supplement. Only 27 of the 109 ingredients did.

The three most common ingredients in testosterone boosters were zinc, fenugreek extract and vitamin B6.

Yet 90 percent of the products claimed to help “low-T.”

Supplements designed to boost testosterone are popular among older men who want to raise their testosterone level without undergoing testosterone replacement therapy. The hope is that the supplements will increase their T in a more natural manner, one that is risk free. Yet that does not appear to be the case.

The University of Southern California team started by doing a Google search for the term “testosterone booster.” Then they looked at the first 50 products that came up, much as a prospective customer might. Each was evaluated for active ingredients and product claims.

Over 100 different ingredients were found in the testosterone supplements tested. The three most common ingredients were zinc, fenugreek extract and vitamin B6.

There was no information at all on the effects of 67 of the ingredients on testosterone level. While 27 did have some evidence of a boosting effect, 11 had published evidence that they decrease testosterone. When it came to ingredients for which multiple studies existed, results were conflicting, and no clear benefit was seen.

“Many supplements on the market merely contain vitamins and minerals, but don't do anything to improve testosterone,” study author, Mary K. Samplaski, said in a statement. “Often, people can be vulnerable to the marketing component of these products, making it difficult to tease out what is myth and what is reality.”

People taking T boosters aren't alone — about half of the adults in the country take some dietary supplement. The United States Food and Drug Administration clearly states that: “Unlike drugs, supplements are not intended to treat, diagnose, prevent, or cure diseases. That means supplements should not make claims, such as “reduces pain” or “treats heart disease.” Yet many of them do.

Samplaski, a specialist in male reproductive medicine at the Keck School of Medicine at USC, would like to see more regulation of testosterone-boosting supplements to protect men. She also is considering giving handouts to her patients with more accurate information in the hope that it will encourage them to seek out a medical professional for help with low-testosterone issues instead of turning to supplements.

The study is published in The World Journal of Men's Health.