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National Center for Complementary and Integrative Health

NCCIH Clinical Digest

for health professionals

Dietary Supplements Marketed for Weight Loss, Bodybuilding, and Sexual Enhancement: What the Science Says

January 2023

Clinical Guidelines, Scientific Literature, Info for Patients: 
Dietary Supplements Marketed for Weight Loss, Bodybuilding, and Sexual Enhancement

Image of dietary supplements

Weight Loss

Most dietary supplements marketed for rapid weight loss, such as acai and hoodia, are ineffective for long-term weight control, and some have serious safety concerns. Researchers have investigated the weight loss potential of a variety of dietary supplements, including green tea extracts, Chinese herbs, and bitter orange extract, but none have been shown to be effective for weight loss, and each has side effects.

What Does the Research Show?

  • Acai berry. No independent studies have been published in peer-reviewed journals that substantiate claims that acai alone promotes rapid weight loss. A 2010 laboratory study examining the safety profile of an acai-fortified juice found no changes in body weight compared with controls.
  • Bitter orange. A  2020 review concluded that bitter orange, as well as other dietary supplements, are unlikely to contribute to meaningful weight loss. A 2004 systematic review of only one eligible randomized controlled trial of 20 people found no statistically significant benefit for weight loss. Similarly, another 2004 review found little evidence that weight loss products containing bitter orange (Citrus aurantium) are an effective aid to weight loss.
  • Ephedra. A 2003 study examining the relative safety of ephedra compared with other herbal products by analyzing phone calls to poison control centers found a higher rate of side effects from ephedra. Other studies and systematic reviews have found an increased risk of heart, psychiatric, and gastrointestinal problems, as well as high blood pressure and stroke, with ephedra use.
  • Green tea. A 2020 review concluded that green tea, as well as other dietary supplements, are unlikely to contribute to meaningful weight loss. A 2012 Cochrane review of 18 randomized controlled trials of at least 12 weeks’ duration in overweight or obese adults found that the loss in weight in adults who had taken a green tea preparation was very small, not statistically significant, and not likely to be clinically important.
  • Mind and body approaches. There is some emerging evidence suggesting that some mind and body approaches, such as yoga and meditation, particularly mindful eating, may be useful as complements to other weight-loss interventions.

Safety

  • The U.S. Food and Drug Administration (FDA) banned the sale of dietary supplements containing ephedra, which were marketed for weight loss, because of serious health risks, such as cardiovascular complications and even risk of death. Ephedra is also called ma huang.
  • Many ephedra-free supplements are now being sold, but side effects of some of their ingredients are similar to those of the banned products. Some ephedra-free supplements also have a lot of caffeine or herbs, such as guarana, that contain caffeine. The products can cause increased heart rate and abnormal heart rhythms.
  • Many dietary supplements marketed for weight loss (including ones sold as “fat burners” or appetite suppressants) have not been tested for safety.

Bodybuilding and Performance Enhancement

Some bodybuilders and athletes use dietary supplements to try to improve their strength, muscle mass, and energy. However, many of these types of products contain harmful ingredients. Also, for some substances, including glutamine, choline, methoxyisoflavone, quercetin, zinc/magnesium aspartate, nitric oxide, and L-arginine, there is no clear evidence that they improve athletic performance.

The National Collegiate Athletic Association (NCAA) maintains a list of banned substances and explains that some dietary supplements may contain banned substances not listed on the product labels. BMPEA (a phenethylamine) and DMAA (dimethylamylamine) are two examples of substances banned by the NCAA.

What Does the Research Show?

  • Studies have looked at a variety of supplements used for bodybuilding or to improve physical performance, including glutamine, choline, methoxyisoflavone, quercetin, zinc/magnesium aspartate, nitric oxide, and L-arginine. There is no clear evidence these supplements improve athletic performance.
  • The results of studies on beta-alanine, an amino acid found in food and dietary supplements, are mixed but generally do not show that it improves athletic performance significantly.
  • Some studies suggest that creatine supplementation may enhance the effects of vigorous exercise on strength, muscle mass, and endurance, but it may also cause fluid weight gain, nausea, cramping, and diarrhea. A 2021 review concluded that daily supplementation of creatine over several days leads to increased concentrations of intramuscular creatine and intramuscular phosphocreatine (PCr), which are associated with a reduction of adenosine triphosphate (ATP) degradation, heightened ATP production, and an increase in energetic output during activities involving intermittent, high-intensity, short bouts of exercise. Additionally, the review found that supplementation with creatine may help facilitate recovery following exercise-induced muscle damage and may aid during post-injury rehabilitation. 

Safety

  • Dangerous hidden ingredients are an increasing problem in products promoted for bodybuilding, the U.S. Food and Drug Administration (FDA) warns. Consumers may unknowingly take products laced with prescription drug ingredients, controlled substances, and other ingredients.
  • Bodybuilding supplements often are adulterated with anabolic steroids that are modified variants of male hormones designed to increase muscle mass.
  • Liver injury from taking bodybuilding dietary supplements has increased in recent years. Bodybuilding products are the most common cause of liver injury linked to herbal and dietary supplement use.
  • Products containing the stimulants BMPEA or DMAA can cause serious health problems.
  • Supplements labeled as containing the herb Acacia rigidula often contain BMPEA, although BMPEA isn’t in the herb and isn’t a dietary ingredient.
  • DMAA-containing products marketed as dietary supplements are illegal. In 2013, the FDA began taking action to remove these products from the market. However, DMAA is still found in some products marketed as supplements, including under different names, such as geranium oil.

Sexual Enhancement

No complementary health approaches have been shown to be safe and effective for sexual enhancement or treating erectile dysfunction (ED). Safety is a serious concern with regard to dietary supplements promoted for ED or sexual enhancement.

What Does the Research Show?

  • Researchers have studied a variety of herbal remedies for ED, but the amount of research on each herb has been small, and much of the research has been done in animals rather than people. Currently, there is no definite evidence that any herbal products are effective or safe for ED.
  • A 2017 prospective, randomized controlled trial in 86 men with mild to moderate ED found that following a 12-week treatment of extracts of the plant Tribulus terrestris, significant improvement in sexual function was observed with Tribulus terrestris compared with placebo. An earlier study (2014) conducted in 30 men with ED found that Tribulus terrestris was not more effective than placebo on improving symptoms of ED or serum total testosterone.

Safety

  • Many supplements promoted for ED and sexual enhancement—sometimes called “herbal Viagra”—have been found to be adulterated with drug ingredients or related substances. Some products include combinations of multiple ingredients or excessively high doses, both of which can be dangerous. Consumers can’t tell whether a product contains these ingredients because they’re not listed on the product label.
  • The drug ingredients in some ED supplements may interact with prescription drugs. For example, some of them may interact with drugs that contain nitrates, leading to a dangerous decrease in blood pressure.

References

NCCIH Clinical Digest is a service of the National Center for Complementary and Integrative Health, NIH, DHHS. NCCIH Clinical Digest, a monthly e-newsletter, offers evidence-based information on complementary health approaches, including scientific literature searches, summaries of NCCIH-funded research, fact sheets for patients, and more.

The National Center for Complementary and Integrative Health is dedicated to exploring complementary health products and practices in the context of rigorous science, training complementary health researchers, and disseminating authoritative information to the public and professionals. For additional information, call NCCIH’s Clearinghouse toll-free at 1-888-644-6226, or visit the NCCIH website at nccih.nih.gov. NCCIH is 1 of 27 institutes and centers at the National Institutes of Health, the Federal focal point for medical research in the United States.

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