A Urologist's Guide to Ingredients Found in Top-Selling Nutraceuticals for Men's Sexual Health
Tao Cui MD; Robert C. Kovell MD; David C. Brooks MD, PhD; and Ryan P. Terlecki MD
ONLINE: November 3, 2015 – The Journal of Sexual Medicine
In the United States, many men are reluctant to discuss sexual health problems with their doctors because they feel embarrassed, worry about drug costs or side effects, and feel there is a stigma associated with such issues. Often, these patients try herbal over-the-counter products, which don’t require a doctor’s prescription and can be taken in private.
This practice comes with risks. Such dietary supplements are considered foods, not drugs, so the U.S. Food and Drug Administration (FDA) has little control over their safety and efficacy.
Some products contain ingredients that can interact with medications a patient might already be taking. It is not uncommon to find undisclosed amounts of prescription drugs, especially phosphodiesterase type 5 inhibitors (PDE5Is), in these supplements.
This study provides an overview of the most common ingredients found in male sexual enhancement products.
Commonly Sold Products
The researchers consulted the website of General Nutrition Corporation (GNC), the largest retailer of dietary supplements in the U.S. They identified the 30 top-selling products marketed to improve men’s sexual health.
Next, the researchers searched Medline and the Natural Medicines database to learn more about the products’ most common active ingredients. They also consulted related studies on erectile function, libido, and sexual performance.
Evidence for Efficacy
The attached chart summarizes the findings on the most common ingredients.
Other Notable Nutraceuticals
The following ingredients were found in the literature search, but were not common in the top-selling supplements:
• L-Carnitine. One study has found that this ingredient can increase nocturnal penile tumescence. Men given L-carnitine had higher scores on the International Index of Erectile Function (IIEF) when compared to men on androgen supplementation. Others show that L-carnitine can strengthen the effects of PDE5Is, especially in diabetic men.
• Antioxidants. These substances are believed to improve erectile function because they relieve oxidative stress and improve NO-mediated vasodilation within the corpora cavernosa. Animal studies have shown improved erectile function with antioxidants, but no human studies have had this result.
The authors noted that most of the products were lacking well-designed studies to determine efficacy and toxicity.
“While certain natural supplements show great promise at improving mild sexual dysfunction, all substances reviewed in this article lack robust human evidence,” they wrote.
They continued, “In addition, concerns of contamination and adulteration are sufficiently worrisome that we would presently caution against routinely recommending dietary supplements for male sexual health.”