Berberine
A plant alkaloid found in barberry and goldthread, studied for its effects on markers of glucose and lipid metabolism. Most of that research has been in people with type 2 diabetes. In a large RCT of diabetes-free people with obesity, **visceral and liver fat did not differ from placebo.** This is not a supplement that melts visceral fat.
An ingredient with growing research
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Effects reported in research
Involvement in glucose and insulin-related markers (research is mainly in people with type 2 diabetes)
Research exists on effects on lipids (LDL cholesterol, apolipoprotein B) and inflammatory markers
In a six-month RCT of diabetes-free people with obesity, visceral fat area and liver fat content did not differ from placebo
Dosage & timing
- Trials have used 1–1.5 g/day, usually split across the day because absorption is low, and typically taken with meals.
- Protocols are not standardised across studies.
- See the linked studies for specific doses and outcomes.
Cautions
- •Berberine lowers blood glucose, so combining it with diabetes medication (metformin, insulin) carries a hypoglycaemia risk — medical supervision is required.
- •It reduced CYP3A4, CYP2D6 and CYP2C9 activity in healthy men (Guo et al., 2012), so **anyone on prescription medication should have every drug they take reviewed by a physician or pharmacist first.** Contraindicated in pregnancy and breastfeeding (uterotonic effects reported).
- •GI symptoms — diarrhoea, nausea, abdominal discomfort — are common at initiation and were reported in 20 patients (34.5%) in Yin et al.
- •(2008); the abstract does not state what that denominator comprises.
- •Long-term safety data at high doses is insufficient.
- •This information is for educational purposes and does not constitute medical advice.
Supporting research
Efficacy of berberine in patients with type 2 diabetes mellitus
Metabolism, 2008
An RCT in 36 newly diagnosed type 2 diabetes patients taking 0.5 g of berberine three times daily (1.5 g/day) for three months, compared against metformin. HbA1c fell from 9.5% to 7.5% and fasting glucose from 10.6 to 6.9 mmol/L — comparable to metformin. Note the comparator was an active drug, not placebo. Transient GI adverse effects were reported in 20 patients (34.5%). The abstract does not state what that denominator comprises; it is not a figure from the 36-patient trial alone.
Overall and Sex-Specific Effect of Berberine on Glycemic and Insulin-Related Traits: a Systematic Review and Meta-Analysis
The Journal of Nutrition, 2023
A meta-analysis of 20 randomized trials of berberine versus placebo (n=1,761). Fasting glucose fell by 0.52 mmol/L (95% CI −0.72 to −0.33; 18 studies, n=1,522) and HbA1c by 4.48 mmol/mol (95% CI −6.53 to −2.44; 7 studies, n=756). Larger effects were suggested in women, in people with diabetes and in Asian participants, though the authors note the limited number of studies means these subgroup comparisons need replication.
Berberine and Adiposity in Diabetes-Free Individuals With Obesity and MASLD: A Randomized Clinical Trial
JAMA Network Open, 2026
A multicenter, double-blind RCT in 337 diabetes-free patients with obesity and MASLD taking 1 g/day of berberine for six months. **The primary endpoints — visceral adipose tissue area (1.4%, 97.5% CI −2.4 to 5.2) and liver fat content (0.9%, 97.5% CI −0.4 to 2.1) — showed no significant difference from placebo.** Among secondary endpoints, LDL cholesterol (−7.72 mg/dL, 95% CI −13.13 to −1.93), apolipoprotein B (−3.42 mg/dL, 95% CI −6.33 to −0.51) and hs-CRP (−0.072 mg/dL, 95% CI −0.140 to −0.004) did differ, but other secondary outcomes did not. These are secondary findings in a trial whose primary endpoints were negative, and are not confirmatory.
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