Berberine: what the evidence says, side effects, drug interactions and who must avoid it

What berberine is

Berberine is a plant alkaloid. It’s found in barberry, goldenseal, Oregon grape and other plants that have long been used in Ayurvedic and traditional Chinese medicine.

On iHerb and in the US, berberine is sold as a herbal supplement. That means it hasn’t been tested the way diabetes or weight-loss medicines are, and quality and doses can differ between products.

This article isn’t a guide to self-treatment. Berberine interacts with many medicines and must not be taken in pregnancy or while breastfeeding. If you’re still considering it, go through the checklist below and take it to your GP.

Berberine benefits: blood sugar and cholesterol

Most berberine research has been in type 2 diabetes:

A 2023 umbrella review confirmed effects on blood sugar, insulin resistance, blood fats and body measurements. Its authors still say the clinical effects need confirming in high-quality randomised trials.

According to the authors of the diabetes review, berberine may be most useful as an add-on to treatment, not a replacement. NCCIH is blunt: don’t replace diabetes treatment with an unproven product.

“Nature’s Ozempic”? Why the comparison doesn’t hold

On TikTok and other platforms, berberine is promoted for weight loss and called “nature’s Ozempic”. The comparison is misleading:

• Ozempic (semaglutide) is a prescription medicine backed by large clinical trials and a well-understood mechanism.
• For berberine, NCCIH calls the weight-loss evidence not conclusive. Many of the studies had a high risk of bias.
• Most people in berberine studies already had diabetes or fatty liver disease. You can’t apply those results to healthy people.
• Doses and formulations varied widely between studies, so there’s no “right” dose for weight loss.
• Most studies were done in Asian countries, and it’s unclear how far the results apply to other groups.

There’s another reason for caution. NCCIH points out that the US FDA warns about diabetes products that seem too good to be true, such as a “natural diabetes cure”. It stresses that you should never replace diabetes treatment with an unproven product.

If your goal is weight loss, start with your GP. Proven treatments for obesity exist, and a supplement doesn’t replace them.

How berberine is taken: doses used in studies

There’s no official dose for self-treatment. NCCIH lists 200–1,000 mg two to three times a day as doses considered safe in clinical settings. Effects on weight appeared mainly above 1 g a day taken for longer than 8 weeks.

• Whether to take it, and how much, is your doctor’s decision, especially if you’re treated for diabetes.
• Studies split the daily amount into 2–3 doses.
• On glucose-lowering medicines, you’ll need to check your blood sugar more often.

Goldenseal isn’t a substitute for berberine. When taken by mouth, very little berberine is absorbed from goldenseal, so berberine study results don’t apply to it. The MSD Manual doesn’t recommend goldenseal.

Berberine side effects

Berberine is generally tolerated, but digestive complaints are common:

• nausea and vomiting;
• stomach pain and bloating;
• constipation or diarrhoea.

According to the MSD Manual, berberine may damage DNA in some cells, though what this means for people isn’t yet known. There’s little data on safety over years of use.

Berberine drug interactions

Berberine and the plants that contain it affect how the liver processes many medicines. Key combinations to know:

If you take any regular medicine, talk to your GP before trying berberine, or take the bottle to your pharmacist. Pick your medicine below to see what’s known about the combination.

Vitamin and mineral combinations are covered in our compatibility chart.

Berberine: what doctors and official sources say

People searching for doctors’ views usually want to know whether berberine is worth taking. Official medical sources are cautious:

• NCCIH, the US federal agency for research on complementary health approaches, says berberine taken by mouth is generally well tolerated but not without risks. It shouldn’t be used in pregnancy, while breastfeeding or in babies, and the weight evidence is not conclusive.
• The MSD Manual doesn’t recommend goldenseal, one source of berberine, because of side effects and drug interactions.
• A 2023 umbrella review concludes that berberine’s effects need confirming in high-quality trials.

Berberine isn’t for everyone. It’s an option to discuss with your GP if you have type 2 diabetes or raised blood fats and understand the risks.

Who should not take berberine

• Pregnant and breastfeeding women. Berberine may harm the baby. In newborns it can cause or worsen jaundice and lead to kernicterus, brain damage from bilirubin.
• Babies must not be given it, and children should only have it if a doctor advises.
• People who’ve had an organ transplant and take ciclosporin.
• People being treated for diabetes, unless their diabetes team agrees.
• People with a seizure disorder or a bleeding disorder should avoid goldenseal.

With any long-term condition, the decision belongs to your doctor.

How to choose berberine on iHerb (if your GP agrees)

1. Go through the safety checklist above and discuss berberine with your GP.
2. Choose berberine HCl with a stated dose per capsule, not goldenseal.
3. Check the ingredients for other active plant extracts.
4. Prefer products with independent quality testing.
5. Agree with your doctor how long to take it and which blood tests to recheck.

If blood sugar is your concern, also read our guide to chromium picolinate: the evidence there is even weaker. For other supplements in this section, see energy and heart, and for heart health read how to choose omega-3.