Berberine Supplements Guide (2026): Evidence-Based Comparisons

What to buy

NutriFlair Berberine + Ceylon Cinnamon is our pick. Two capsules give 1,200 mg, in the range many trials used, for $0.47 a day at its brand price. Like most berberine, it is on no public testing list.

Want one on a public testing list? NSF/ANSI 173, which checks that a product matches its label, lists Toniiq Berberine.

Where to go next

• Best berberine: the products we compared, ranked.
• Berberine dosage guide: label servings, splitting across meals, and a calculator.
• Berberine for weight loss: what trials found and how to take it.
• Third-party tested berberine: which brands are on NSF’s list.

What berberine does

Most trials were in adults with type 2 diabetes, high cholesterol, metabolic syndrome, fatty liver or PCOS, mostly in China. We found no trial of berberine alone in healthy adults who only want to lose weight.

How long the trials ran

Many trials ran about 12 weeks, giving 1,000 to 1,500 mg a day, often split into 2 or 3 doses. In one review, the drop in fasting blood sugar showed up in trials longer than 8 weeks (Zamani 2022). See the dosage guide.

Side effects and drug cautions

• Upset stomach, like diarrhea or constipation, is the most common side effect. In reviews, it was reported by 2% to 23% of people on berberine vs 2% to 15% on a placebo pill (Blais 2023). In one trial, stomach effects eased during the first month (Bandala 2024).
• Diabetes medicines: berberine adds to the blood-sugar drop from diabetes drugs, so your blood sugar may go too low. In reviews, berberine plus a diabetes drug lowered blood sugar more than the drug alone (Liang 2019; Dong 2012). Ask your doctor before you mix them.
• Other medicines: in healthy men, taken 300 mg three times a day for 2 weeks, berberine slowed three liver enzymes that clear many drugs, and the blood level of one test drug (midazolam) rose 40% (Guo 2012).
• In kidney transplant patients, berberine raised levels of the anti-rejection drug cyclosporine by about a third (34.5%; Wu 2005). So berberine may raise levels of other medicines too. Ask a pharmacist before you take it with any prescription.
• Pregnancy and breastfeeding: NCCIH says pregnant or breastfeeding women should not use goldenseal, which contains berberine, and that its berberine can harm newborns. In lab and rat tests it pushed bilirubin off its carrier protein, which raises concern about newborn jaundice (Chan 1993). Ask your doctor.

Questions people ask