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Research · Supplements

Berberine

In type 2 diabetes, berberine lowered HbA1c by 0.63 points across 37 trials, with no difference from metformin and other diabetes drugs. It lowered LDL by 0.46 mmol/L and body weight by 0.88 kg. Most lipid trials were in China. An integrity review excluded all four PCOS trials. Berberine slowed CYP2D6, 2C9 and 3A4 and raised cyclosporine levels.

Add to Bio HackChecked 2026-11-09
Status
Dietary supplement in the US.
Also called
berberine HCl, berberine hydrochloride, Coptis, goldenseal alkaloid, Berberis, nature's Ozempic
Taken for
blood sugar, type 2 diabetes, weight loss, cholesterol, triglycerides, PCOS, insulin resistance

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help4

Reported risks3

What people take it for, and what was found

Shown to help4

Strong

Blood sugar in type 2 diabetes

Shown to lower fasting glucose and HbA1c in adults with type 2 diabetes, with HbA1c about 0.6 points lower. Many trials were small and low quality.

The numbers and sources
Effect
Across 37 trials (3,048 patients), berberine lowered fasting glucose by 0.82 mmol/L (95% CI -0.95 to -0.70), HbA1c by 0.63% (95% CI -0.72 to -0.53) and 2-hour glucose by 1.16 mmol/L, with larger effects at higher baseline glucose [1]. Against placebo in 20 trials (1,761 participants), it lowered fasting glucose by 0.52 mmol/L (95% CI -0.72 to -0.33) and HOMA-IR by 0.85 [2].
Population
Adults with type 2 diabetes [1]. Adults with and without diabetes [2].
Sources
[1], [2]
Caveats
Effects on fasting glucose were larger in people with diabetes and in Asian participants [2]. Many trials were small and of low methodological quality [3].
Moderate

Compared with metformin and other diabetes drugs

Shown to lower blood sugar about as much as metformin and other oral diabetes drugs in adults with type 2 diabetes, in mostly low-quality trials.

The numbers and sources
Effect
In 14 trials (1,068 participants), berberine did not give better glucose control than metformin, glipizide or rosiglitazone, and added to the same drug it gave better control than the drug alone [3]. A 27-trial meta-analysis (2,569 patients) found no significant difference between berberine and oral diabetes drugs [4]. In 36 adults with new type 2 diabetes, 0.5 g of berberine or metformin three times a day for 3 months gave similar glucose lowering, with HbA1c falling from 9.5% to 7.5% on berberine [5]. In 89 women with PCOS, berberine reduced waist-to-hip ratio and LDL more than metformin over 3 months [6].
Population
Adults with type 2 diabetes [3][4][5]. Chinese women with PCOS and insulin resistance [6].
Sources
[3], [4], [5], [6]
Caveats
Methodological quality was generally low [3]. The 36-person comparison was a pilot [5]. An integrity review rated every PCOS trial it found at high risk of compromised integrity [7].
Strong

Cholesterol and triglycerides

Shown to lower LDL by about 0.46 mmol/L and lower triglycerides in adults, in trials mostly from China and Hong Kong.

The numbers and sources
Effect
In 18 placebo-controlled trials (1,788 participants), berberine lowered LDL by 0.46 mmol/L (95% CI -0.62 to -0.30), total cholesterol by 0.48 mmol/L and triglycerides by 0.34 mmol/L, and raised HDL by 0.06 mmol/L. The HDL rise was seen in women and not in men [8]. A 27-trial meta-analysis found berberine combined with lipid drugs lowered cholesterol more than the drugs alone [4].
Population
Adults, mostly in mainland China and Hong Kong, for 4 to 24 weeks [8].
Sources
[4], [8]
Caveats
15 of the 18 trials were in mainland China or Hong Kong [8].
Moderate

Body weight

Shown to lower body weight by about 0.9 kg in adults. A 6-month trial found no change in visceral or liver fat.

The numbers and sources
Effect
Across 23 RCTs, berberine lowered body weight by 0.88 kg (95% CI -1.36 to -0.39), BMI by 0.48 kg/m² and waist circumference by 1.32, with no change in waist-to-hip ratio [9]. In a 6-month double-blind trial, 1 g a day did not change visceral fat area (difference 1.4%, 97.5% CI -2.4% to 5.2%) or liver fat content (0.9%, 97.5% CI -0.4% to 2.1%) against placebo [10].
Population
Adults [9]. 337 adults without diabetes with obesity and fatty liver disease at 11 hospitals in China [10].
Sources
[9], [10]
Caveats
The authors call for better reporting of purity, potency and dose, and note lack of blinding and randomization in some trials [9]. The 6-month trial measured fat by CT and its abstract does not report body weight [10].

Mixed results1

LimitedStudied in women

PCOS

Limited evidence: all 4 PCOS trials were rated at high risk of compromised integrity, so their reported improvements were judged not reliable.

The numbers and sources
Effect
An integrity-based systematic review found 4 RCTs of berberine in polycystic ovary syndrome. All four were rated at high risk of compromised integrity, with absent trial registration, implausible recruitment timelines and possible duplicated data, so none was pooled. The reported improvements in insulin resistance, lipids and androgen markers were judged not reliable [7].
Population
452 women with polycystic ovary syndrome, now also called polyendocrine metabolic ovarian syndrome [7].
Sources
[7]
Caveats
Trial authors did not answer requests for clarification [7]. The abstract does not name the four trials, so it does not show whether the PCOS trial in [6] was among them.

Doses studied

Diabetes trials used 0.5 g three times a day for 3 months [5]. The enzyme interaction study used 300 mg three times a day for 2 weeks [11]. The cyclosporine trial used 0.2 g three times a day for 3 months [12]. The visceral fat trial used 1 g a day for 6 months [10].

Risks

Reported risks3

ModerateVery common

Gastrointestinal effects

Gastrointestinal side effects ran 2% to 23% on berberine against 2% to 15% on placebo, with no serious adverse events reported in 16 trials.

The numbers and sources
How common
Very common: more than 1 in 10 people.
Effect
In one diabetes trial, 34.5% of patients had transient gastrointestinal side effects, with no liver or kidney damage found [5]. Across lipid trials, gastrointestinal events were 2% to 23% with berberine and 2% to 15% with placebo, and no serious adverse events were reported in 16 trials [8]. In diabetes trials, total adverse events were lower with berberine (RR 0.73, 95% CI 0.55 to 0.97), and hypoglycemia did not differ (RR 0.48, 95% CI 0.21 to 1.08) [1].
Population
Trial participants [1][5][8].
Sources
[1], [5], [8]
Caveats
Trials ran up to 24 weeks.
ModerateHow often is not known

Drug-metabolizing enzyme inhibition

Shown to raise levels of drugs cleared by CYP2D6, CYP2C9 and CYP3A4 in healthy men, and cyclosporine levels by about 29% in kidney transplant recipients.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
In healthy men, 300 mg three times a day for 2 weeks raised the dextromethorphan ratio ninefold (CYP2D6), doubled the losartan ratio (CYP2C9), and raised midazolam AUC by 40% with 27% lower clearance (CYP3A4) [11]. In 52 kidney transplant recipients, cyclosporine trough levels ended 29.3% higher with berberine than without. In 6 patients, cyclosporine AUC rose 34.5% after 12 days [12].
Population
Healthy male volunteers [11]. Kidney transplant recipients [12].
Sources
[11], [12]
Caveats
Probe-drug and transplant studies. Other enzymes tested (CYP2C19, CYP1A2) did not change [11].
LimitedHow often is not known

Heart rhythm

Case reports: a woman with prolonged QT had a dangerous arrhythmia and cardiac arrest after months of berberine, which resolved after stopping.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
A 36-year-old woman with prolonged QT developed torsades de pointes and cardiac arrest after several months of berberine bought online. Her symptoms and EKG changes resolved after stopping it [13]. A 2026 systematic review of 22 studies listed prolonged QT interval, slow heart rate and low blood pressure among berberine's cardiovascular side effects, and reported that berberine inhibits the hERG potassium channel [14].
Population
Single case report [13]. 22 studies [14].
Sources
[13], [14]
Caveats
One case cannot show cause or rate. The review abstract does not separate human from animal or cell studies or give rates [14].

Claims tested and not found

  1. That berberine controls blood sugar better than metformin. Glucose control did not differ significantly from oral diabetes drugs, including metformin [3][4].
  2. That berberine reduces waist-to-hip ratio. Pooled waist-to-hip ratio did not change [9].
  3. That berberine reduces visceral or liver fat. Over 6 months, neither differed from placebo in 337 adults with obesity and fatty liver disease [10].

Sources

  1. Xie W, Su F, Wang G, et al. Glucose-lowering effect of berberine on type 2 diabetes: A systematic review and meta-analysis. Frontiers in Pharmacology. 2022. https://doi.org/10.3389/fphar.2022.1015045
  2. Zhao JV, Huang X, Zhang J, et al. Overall and Sex-Specific Effect of Berberine on Glycemic and Insulin-Related Traits: a Systematic Review and Meta-Analysis of Randomized Controlled Trials. The Journal of Nutrition. 2023. https://doi.org/10.1016/j.tjnut.2023.08.016
  3. Dong H, Wang N, Zhao L, Lu F. Berberine in the Treatment of Type 2 Diabetes Mellitus: A Systemic Review and Meta-Analysis. Evidence-Based Complementary and Alternative Medicine. 2012. https://doi.org/10.1155/2012/591654
  4. Lan J, Zhao Y, Dong F, et al. Meta-analysis of the effect and safety of berberine in the treatment of type 2 diabetes mellitus, hyperlipemia and hypertension. Journal of Ethnopharmacology. 2015. https://doi.org/10.1016/j.jep.2014.09.049
  5. Yin J, Xing H, Ye J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism. 2008. https://doi.org/10.1016/j.metabol.2008.01.013
  6. Wei W, Zhao H, Wang A, et al. A clinical study on the short-term effect of berberine in comparison to metformin on the metabolic characteristics of women with polycystic ovary syndrome. European Journal of Endocrinology. 2012. https://doi.org/10.1530/EJE-11-0616
  7. Perera E, Mantzioris E, Moran L, et al. Questionable Evidence for Berberine in Polyendocrine Metabolic Ovarian Syndrome: An Integrity-Based Reappraisal. Advances in Therapy. 2026. https://doi.org/10.1007/s12325-026-03799-7
  8. Blais JE, Huang X, Zhao JV. Overall and Sex-Specific Effect of Berberine for the Treatment of Dyslipidemia in Adults: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials. Drugs. 2023. https://doi.org/10.1007/s40265-023-01841-4
  9. Elahi Vahed I, Shahir-Roudi E, Nojumi S, et al. The effect of berberine on obesity indices: a systematic review and meta-analysis. International Journal of Obesity. 2026. https://doi.org/10.1038/s41366-025-01943-x
  10. Lei L, Wang B, Zhao L, et al. Berberine and Adiposity in Diabetes-Free Individuals With Obesity and MASLD. JAMA Network Open. 2026. https://doi.org/10.1001/jamanetworkopen.2025.54152
  11. Guo Y, Chen Y, Tan ZR, et al. Repeated administration of berberine inhibits cytochromes P450 in humans. European Journal of Clinical Pharmacology. 2012. https://doi.org/10.1007/s00228-011-1108-2
  12. Wu X, Li Q, Xin H, et al. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. European Journal of Clinical Pharmacology. 2005. https://doi.org/10.1007/s00228-005-0952-3
  13. Williams JM, Yadlapalli N, Franchi F. Natural Is Not Always Safe: A Case of Torsades De Pointes Induced by Berberine Supplementation. Cureus. 2026. https://doi.org/10.7759/cureus.111276
  14. Masoumi S, Moetazedian M, Jafari S, et al. Mechanistic Effects and Complications of Berberine on Cardiac Arrhythmias: A Systematic Review. Current Reviews in Clinical and Experimental Pharmacology. 2026. https://doi.org/10.2174/0127724328346501250404175826

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