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. In 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 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 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.
- There’s 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.
- The U.S. Food and Drug Administration (FDA) banned the sale of dietary supplements containing ephedra, which was 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 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.
Some bodybuilders and athletes turn to dietary supplements to help them increase muscle size and definition. However, many bodybuilding products marketed as dietary supplements have been found to contain other ingredients that can be harmful.
What Does the Research Show?
- There is no scientific evidence that other dietary supplements, such as choline, methoxyisoflavone, zinc/magnesium aspartate, nitric oxide precursors, and chromium, are effective for building strength and muscle mass.
- 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 2018 review concluded that the current scientific literature best supports creatine supplementation for increased performance in short-duration, maximal-intensity resistance training. The review also concluded that it remains unknown if creatine supplementation leads to improved athletic performance on the field.
- Many bodybuilding products marketed as dietary supplements have been found to be deceptively labeled and to contain hidden ingredients that can be harmful, such as anabolic steroids, compounds chemically similar to them, or other substances that don’t qualify as dietary ingredients.
- In April 2013, the U.S. Food and Drug Administration issued a warning to consumers to avoid products containing the stimulant dimethylamylamine (DMAA). DMAA can elevate blood pressure and lead to other cardiovascular problems.
- Creatine supplements may be safe for short-term use in healthy adults, but the American College of Sports Medicine recommends against anyone younger than age 18 using it to enhance athletic performance. The safety of creatine supplementation has not been studied in children and adolescents.
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.
- 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.
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U.S. Food and Drug Administration. SMAA in Dietary Supplements. Available at: https://www.fda.gov/Food/DietarySupplements/ProductsIngredients/ucm346576.htm. Accessed on January 10, 2018.