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Plant alkaloid (barberry, goldenseal)

Berberine

Berberine modestly lowers blood sugar in type 2 diabetes and slightly lowers LDL cholesterol and triglycerides, but it is not a harmless supplement: it changes how the body handles many medicines and should not be used in pregnancy, while breastfeeding or by babies. Almost all the trials are small, short and from China, with weak blinding, so the true effect is likely smaller than the pooled figures.

It is not 'nature's Ozempic': weight meta-analyses find under 1 kg of loss on average, and one found none, while stomach upsets such as constipation and diarrhoea are common.

Updated
10 October 2026
Bright yellow berberine capsules with barberry berries
At a glance
Last reviewed 10 October 2026
Evidence
Moderate
Best for
High blood sugar
Typical form & use
Berberine, 900–1,500 mg daily, split
Onset
4+ weeks
Safety
Many drug interactions; never in pregnancy or for babies. 8 known interactions, most serious with diabetes medication.
Check with your medications →

What it's used for

Evidence is rated per use. The same ingredient can be strong for one thing and traditional for another.

UseEvidenceWhat the research shows
Blood sugar in type 2 diabetesCompare remedies for blood sugar →Moderate

A 2022 meta-analysis of 37 trials (3,048 people with type 2 diabetes) found berberine, alone or added to diabetes drugs, lowered HbA1c by 0.63 percentage points and fasting glucose by 0.82 mmol/L, with larger effects when starting levels were higher. But 36 of the 37 trials were in China, only 3 described allocation concealment and 6 blinding.

Pooling only placebo-controlled trials (20 studies, 1,761 people, not all with diabetes) gave smaller drops: fasting glucose 0.52 mmol/L and HbA1c 4.48 mmol/mol (about 0.4 percentage points).1,2

Raised cholesterol and triglyceridesCompare remedies for heart health →Moderate

A 2023 meta-analysis of 18 placebo-controlled trials (1,788 adults, 900–1,500 mg a day for 4 to 24 weeks) found berberine lowered LDL cholesterol by 0.46 mmol/L (about 18 mg/dL) and triglycerides by 0.34 mmol/L (about 30 mg/dL), and raised HDL slightly. Fifteen of the 18 trials were from mainland China and Hong Kong, and none measured heart attacks or strokes.4

Polycystic ovary syndrome (PCOS)Compare remedies for women’s health →Limited

A 2019 review of 12 trials found berberine lowered total testosterone and the LH/FSH hormone ratio compared with placebo or no treatment, but it found no solid evidence that berberine improves live birth: rates were similar to placebo or metformin and lower than with the fertility drug letrozole.7

Weight lossLimited

A 2025 meta-analysis of 23 trials found berberine lowered body weight by 0.88 kg and BMI by 0.48 on average, and its authors flagged a common lack of blinding and randomisation. An earlier meta-analysis of 10 trials found a small drop in BMI (0.29) and waist size (2.75 cm) but no significant change in body weight (0.11 kg). NCCIH says there is not enough rigorous evidence to know whether it works for weight loss.5,6,8

How much

Ranges below are what studies used and what supplements commonly contain. They are not a recommendation for you. Start at the low end.

Studied range
900–1,500 mg a day, split1,4
Thirty of the 37 diabetes trials used 0.9 to 1.5 g a day, and the placebo-controlled cholesterol trials used 900 to 1,500 mg. Trials lasted 2 weeks to 6 months.
Typical trial schedule
500 mg three times a day3
Used in a 3-month pilot in adults with newly diagnosed type 2 diabetes, where about a third of patients had passing stomach side effects.
Upper limit
Not established10
No safe upper limit has been set. France's food safety agency found effects on the body from 400 mg a day, a draft EFSA opinion concluded no safe intake could be set for berberine-containing plant preparations, and national limits in the EU differ widely (Belgium caps these alkaloids at 10 mg a day).
Timing · Trials split the daily dose into two or three portions, typically 300–500 mg each time. The sources we read do not compare times of day.With food? · The sources we read do not say whether to take it with or without food.How long to trial · In one pilot, fasting and after-meal glucose fell from the first week, but most trials judged HbA1c and cholesterol after 1 to 3 months. Long-term safety beyond about 6 months is unknown.

How people take it

Purified berberine (capsule or tablet)900–1,500 mg a day, splitThe form used in the trials, usually as berberine hydrochloride. Products are not standardised, so the dose delivered can vary.
Berberine-containing herbs (goldenseal, barberry, goldthread)Varies; berberine content rarely statedBerberine is found naturally in these plants. Trials of purified berberine do not tell you what a whole-herb product will do, and goldenseal has its own interactions.

Safety

Who should avoid
  • Pregnancy and breastfeeding — NCCIH says not to use it
  • Babies — it can cause or worsen newborn jaundice and risk kernicterus
  • Taking ciclosporin or tacrolimus — berberine raised ciclosporin blood levels
  • Taking diabetes medicines — ask first; blood sugar may fall further
  • Taking several prescription medicines — it slows enzymes that clear many drugs
Known interactions
CautionDiabetes medication — Berberine lowers blood sugar, so effects may add up with insulin, sulfonylureas and other diabetes drugs; a berberine-rich goldenseal extract also lowered metformin levels in healthy volunteers.
CautionImmunosuppressants — In kidney-transplant patients, berberine 200 mg three times daily raised ciclosporin exposure by about a third (trough levels 29% above controls), most likely by blocking the CYP3A4 enzyme that clears it.
CautionSedatives & sleep medication — Two weeks of berberine 300 mg three times daily raised blood levels of the sedative midazolam by about 40% by slowing the CYP3A4 enzyme.
MonitorBlood pressure medication — Berberine may add to the effect of blood pressure drugs and beta-blockers, risking low blood pressure or a slow pulse.
MonitorBlood thinners — Berberine slowed the CYP2C9 enzyme in humans, which clears warfarin, so a stronger anticoagulant effect is possible; no warfarin study exists.
MonitorDigoxin & heart-rhythm medication — In animal studies berberine raised digoxin absorption through the P-glycoprotein transporter, and a review flags a possible added risk with drugs that prolong the QT interval.
MonitorAntidepressants (SSRIs) — Berberine strongly slowed the CYP2D6 enzyme in healthy men, which clears several antidepressants; no study has measured the effect on a specific antidepressant.
MonitorStatins (cholesterol medication) — Laboratory and mechanism data suggest berberine could raise simvastatin or atorvastatin levels and muscle-side-effect risk; there is no human study.

Questions people ask

What are the side effects of berberine?

Mostly stomach and bowel problems: NCCIH lists abdominal pain, constipation, diarrhoea, nausea and vomiting, and about a third of people in one 3-month diabetes pilot had passing stomach side effects.

In placebo-controlled cholesterol trials, stomach upsets affected 2–23% on berberine against 2–15% on placebo, with no serious events, but those trials lasted 24 weeks at most. The bigger risks are drug interactions and harm to newborns.

Is berberine 'nature's Ozempic'?

No. That label comes from social media, not trials. The largest weight meta-analysis found an average loss of under 1 kg, another found no significant weight change, and NCCIH says there is not enough rigorous evidence to know whether berberine helps with weight loss. No study has tested it alongside semaglutide or similar drugs.

Is berberine as good as metformin?

That has not been shown. In one 3-month pilot of 36 adults with newly diagnosed type 2 diabetes, berberine and metformin (each 500 mg three times a day) lowered blood sugar by similar amounts, but that trial was too small to settle the question, and in PCOS live birth rates were similar with either.

Berberine is not a substitute for prescribed diabetes treatment, and a berberine-rich goldenseal extract lowered metformin levels, so ask your prescriber before combining them.

Can I take berberine while pregnant or breastfeeding?

No. NCCIH says people who are pregnant or breastfeeding should not use berberine and it should not be given to babies, because it can cause or worsen jaundice in newborns and could lead to kernicterus, a life-threatening form of brain damage from bilirubin.

Sources (10)

  1. Systematic review and meta-analysis Xie W, Su F, Wang G, Peng Z, Xu Y, Zhang Y, Xu N, Hou K, Hu Z, Chen Y, Chen R. Glucose-lowering effect of berberine on type 2 diabetes: A systematic review and meta-analysis. Front Pharmacol. 2022.
  2. Systematic review and meta-analysis Zhao JV, Huang X, Zhang J, Chan YH, Tse HF, Blais JE. Overall and Sex-Specific Effect of Berberine on Glycemic and Insulin-Related Traits: a Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Nutr. 2023.
  3. Randomised controlled trial (pilot) Yin J, Xing H, Ye J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism. 2008.
  4. Systematic review and meta-analysis 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.
  5. Systematic review and meta-analysis Elahi Vahed I, Shahir-Roudi E, Nojumi S, et al. The effect of berberine on obesity indices: a systematic review and meta-analysis. Int J Obes (Lond). 2026.
  6. Systematic review and meta-analysis Xiong P, Niu L, Talaei S, et al. The effect of berberine supplementation on obesity indices: A dose-response meta-analysis and systematic review of randomized controlled trials. Complement Ther Clin Pract. 2020.
  7. Systematic review and meta-analysis Xie L, Zhang D, Ma H, et al. The Effect of Berberine on Reproduction and Metabolism in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis of Randomized Control Trials. Evid Based Complement Alternat Med. 2019.
  8. Government health information National Center for Complementary and Integrative Health (NCCIH). In the News: Berberine. Updated June 2023.
  9. Randomised crossover trial Guo Y, Chen Y, Tan ZR, Klaassen CD, Zhou HH. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol. 2012.
  10. Narrative review Dumitru CN, Marcu T, Dumitru AO, Tudor SS, Ferțu ID, Elisei AM, Goroftei L. Berberine-Drug Interactions: Mechanisms, Clinical Relevance and Risk Stratification-A Narrative Review. Pharmaceuticals (Basel). 2026.

Reader notes

Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.

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Last reviewed 10 October 2026 · Next review April 2027 · How we rate evidence