Weight Loss Fad Berberine (“Nature’s Ozempic”) Lacks Rigorous Evidence, Has Potential Harms

Jennifer Middleton, MD, MPH
Posted on July 3, 2023

The interest in semaglutide (Ozempic and Wegovy) has not waned in the United States since I wrote about its popularity for weight loss earlier this year. Semaglutide’s cost and intermittent drug shortages, however, have made it difficult for many to access. Enter berberine, an over-the-counter herbal supplement most commonly derived from the berry (barberry) of the berberis shrub; it’s become a social media superstar over the last few weeks, as TikTokers tout its weight loss benefits at a fraction of the cost of semaglutide. Rigorous data demonstrating benefit from berberine are lacking, though, and it can also interact with medications that are metabolized by the liver.

Berberine has been used in Traditional Chinese Medicine for more than 2,000 years for both diabetes and gastrointestinal symptoms, primarily diarrhea. Participants with type 2 diabetes in a very small pilot study from 2008 showed equivalent glucose lowering with berberine as with metformin. A slightly larger randomized study comparing berberine with placebo found decreases in both blood glucose and lipid levels in participants taking berberine. A 2018 systematic review of randomized controlled trials comparing berberine to either placebo or to approved prescription hypoglycemic medications found berberine superior to comparison groups regarding fasting and/or postprandial glucose levels; included trials were deemed to be of “low to moderate” quality.

These studies demonstrated only disease-oriented outcomes (instead of Patient-Oriented Evidence that Matters) on a relatively small scale with methodological concerns. “There has never been a large-scale, randomized (some get a placebo while others get treatment drug) or multicenter clinical trial, which new diabetes drugs need to undergo to obtain FDA approval.” Berberine is sold as a dietary supplement in the United States, and the Food and Drug Administration (FDA) “does NOT have the authority to approve dietary supplements for safety and effectiveness.” As with all dietary supplements, it’s impossible to know for sure whether the ingredients listed on the bottle accurately represent what’s inside the bottle. Berberine also has multiple known interactions with medications that are metabolized by the liver, including metformin.

Family physicians should be aware of these social media fads so that we can effectively counsel our patients about them. Regarding berberine, we can start by validating our patients’ desire to improve their health (while also recognizing, when indicated, that our culture’s obsession with thinness is largely fueled by the diet industry). With a lack of rigorous efficacy and safety studies, a known risk of interacting with several common medications, and the inability to trust that any supplement actually contains what’s on its label, we also need to advise patients to exercise caution regarding berberine’s use.

The FDA website has patient education materials about dietary supplements that may be useful to refer to your patients, and this 2017 AFP article reviews other “Common Herbal-Dietary Drug Interactions.” If you’d like to read more, there are AFP STEPS reviews on Ozempic and Wegovy and AFP By Topics on Obesity and Diabetes Type 2.