The most common berberine side effects are digestive: nausea, stomach pain, bloating, gas, constipation or diarrhea. They're usually mild to moderate. The bigger safety questions are medicine interactions and pregnancy. Berberine can change how your body processes some medicines, and it isn't considered safe during pregnancy, breastfeeding or for infants.
Berberine is a yellow plant compound found in barberry, goldenseal, Oregon grape and tree turmeric. If you want the research background, our berberine guide covers it. This article is only about safety: what side effects people report, how the dose on a label lines up with research, who should skip it, and what to ask your pharmacist before your first capsule.
Last reviewed: October 31, 2026.
Key Takeaways
- Digestive symptoms are the side effects reported most often. In one small 3-month study, 34.5% of participants had short-lived stomach or bowel effects.
- NCCIH says berberine is considered safe at the doses used in clinical settings, 200 to 1,000 mg two to three times a day.
- In healthy men, 300 mg three times a day for 2 weeks slowed three liver enzymes (CYP3A4, CYP2D6 and CYP2C9) that clear many common medicines.
- Don't use berberine if you're pregnant or breastfeeding, and never give it to infants.
- LiverTox, the NIH liver-safety database, has not linked berberine to liver enzyme rises or to clinically apparent liver injury.
What are the most common berberine side effects?
The side effects reported most often are in the gut. NCCIH lists nausea, abdominal pain, bloating, constipation and diarrhea, and describes the common ones as mild to moderate (NCCIH, berberine and weight loss; NCCIH, dietary supplements fact sheet).
How often does it happen? In a small 3-month pilot study, 34.5% of participants taking berberine had transient gastrointestinal effects (Yin et al., 2008). Larger pooled analyses give a calmer picture. A 2018 review of 16 trials with 2,147 participants found no significant difference in adverse events between berberine and control groups, and no severe adverse effects in either group (Ju et al., 2018). A 2023 umbrella review of 11 meta-analyses also named constipation and diarrhea as the common side effects (Li et al., 2023).
The authors of both reviews flagged weak study quality, so treat these numbers as a rough guide, not a promise of how you'll feel.
How can you lower the chance of stomach upset?
There isn't a trial that tests tricks for avoiding berberine's stomach effects, so here's what the research and labels do tell us:
- Follow the label. The human studies in this article gave berberine in divided doses, two or three times a day. Our label says to take it during your eating window, so with your meals rather than on an empty stomach.
- Don't stack products. Goldenseal, barberry and Oregon grape products can also contain berberine. Taking two at once raises your total without you noticing.
- Keep notes for the first two weeks. Write down when you take it, what you ate and how your stomach felt. It makes the conversation with your doctor much easier if something feels off.
- Ask about a lower start. If you have a sensitive stomach, ask your healthcare professional whether you should begin with less than the full label amount.
Is berberine safe to take every day?
For healthy adults, NCCIH says berberine is considered safe at doses used in clinical research: 200 to 1,000 mg, two to three times a day (NCCIH). The studies cited in this article ran from 2 weeks to 3 months. There's far less data on taking it for years, so long-term safety is less certain.
That's one reason to check in with your healthcare professional if you plan to take berberine for months at a time. Berberine has also been studied for its effects on blood sugar, so if you take any prescription medicine, ask whether the two could add up.
What dose of berberine do labels and studies use?
Here's how the numbers line up. This is a safety comparison, not a dosing recommendation for you.
| Source | Amount | How it was taken |
|---|---|---|
| NCCIH clinical range | 200 to 1,000 mg per dose | Two to three times a day |
| Yin et al., 2008 (3 months) | 500 mg per dose, 1,500 mg a day | Three times a day |
| Guo et al., 2012 (2 weeks) | 300 mg per dose, 900 mg a day | Three times a day |
| Wu et al., 2005 (3 months) | 200 mg per dose, 600 mg a day | Three times a day |
| OPA Berberine Plus label | 1,200 mg berberine HCl blend per 2-capsule serving | Two capsules a day during your eating window |
Two practical points. First, "berberine HCl" is the salt form most products and studies use, so read the Supplement Facts panel for the amount per serving, not per capsule. Our guide to reading a Supplement Facts label walks through it. Second, more isn't better. If a serving looks higher than you expected, check with your pharmacist before taking it.
Which medicines can interact with berberine?
This is the side effect you can't feel, which is why it matters most. Berberine can slow the liver enzymes that break down many medicines. When those enzymes slow down, a medicine can build up in your blood.
In a crossover study of healthy men, 300 mg of berberine three times a day for 2 weeks reduced the activity of CYP2D6, CYP2C9 and CYP3A4. Exposure to a test drug cleared by CYP3A4 rose by about 40%. The authors concluded that drug interactions "should be considered" when berberine is used (Guo et al., 2012).
The clearest real-world example involves cyclosporine, a transplant medicine. In 52 kidney-transplant patients who took 200 mg of berberine three times a day for 3 months, cyclosporine blood levels ended up about 29% higher than in patients who didn't take berberine (Wu et al., 2005). NCCIH cites this interaction too.
Herbs count as well. NCCIH notes that goldenseal, which contains berberine, may change the way your body processes many medications (NCCIH, goldenseal). The FDA warns that mixing supplements and medicines can lead to unwanted effects and that "natural does not always mean safe" (FDA).
Contains berberine. Talk to your healthcare professional before use if you take any medication.
What should you ask your pharmacist before you start?
Pharmacists see your whole medicine list, so they're the best people to check interactions. Bring the bottle or a photo of the label. These questions cover most of it:
| Ask this | Why it matters |
|---|---|
| Are any of my medicines cleared by CYP3A4, CYP2D6 or CYP2C9? | Berberine slowed all three enzymes in a human study. |
| Do I take anything with a narrow safe range? | Small rises in blood levels matter most for these medicines. |
| Could berberine add to the effect of something I already take? | Two products pushing in the same direction can add up. |
| Do any of my other supplements also contain berberine? | Goldenseal, barberry and Oregon grape products can. |
| Should I space it apart from any medicine, or skip it? | Your pharmacist can look at timing for your specific list. |
| Do I have a procedure coming up? | The FDA notes some supplements interact with medicines used around surgery. |
The NIH Office of Dietary Supplements also suggests keeping a written record of every supplement and medicine you take, and sharing it with your doctors, dentists and pharmacists (ODS).
Who should not take berberine?
- Pregnant or breastfeeding women. NCCIH says berberine should not be used during pregnancy or while breastfeeding.
- Infants and children. NCCIH says berberine has been linked to a harmful buildup of bilirubin in infants, which can cause brain damage (NCCIH). Lab research found berberine pushes bilirubin off its carrier protein in the blood, and the author advised avoiding it in jaundiced newborns and pregnant women (Chan, 1993). Our label is for adults; anyone under 18 should talk with a healthcare professional first.
- People taking cyclosporine or other medicines with known enzyme interactions, unless their prescriber says otherwise.
- Anyone with an ongoing medical condition or who takes prescription medicine, until they've checked with their healthcare professional.
Talk to your healthcare professional before use if you are pregnant, nursing, or taking any medication.
Is berberine hard on the liver or kidneys?
The human data so far is reassuring, though limited. LiverTox, the NIH database on drug and supplement liver injury, says berberine "has not been linked to serum aminotransferase elevations during therapy nor to instances of clinically apparent liver injury" (LiverTox, 2020). In the 3-month pilot study, no liver or kidney problems were seen in any participant (Yin et al., 2008). In the transplant study, berberine had no significant effect on liver or kidney function tests (Wu et al., 2005).
Because berberine affects the liver enzymes that clear many medicines, people with existing liver or kidney concerns should still get their doctor's OK first.
When should you stop taking berberine?
Stop and call your healthcare professional if you notice any of these:
- Stomach pain, vomiting or diarrhea that's severe or lasts more than a few days
- Yellowing of the skin or eyes, or unusually dark urine
- A rash, itching or swelling
- Feeling shaky, dizzy or unusually tired
- A new or stronger side effect from a medicine you already take
If you think a supplement caused a serious reaction, the FDA asks you to stop using the product and file a report through its Safety Reporting Portal (FDA).
How do you choose a berberine supplement you can trust?
Unlike medicines, supplements don't need FDA approval before they're sold (ODS), so quality varies from brand to brand. NCCIH has noted that some goldenseal products contained other herbs or ingredients not listed on the label, or instead of goldenseal (NCCIH). A few habits help:
- Check that the form (berberine HCl) and the amount per serving are both listed.
- Look for the plant source, such as Berberis aristata.
- Read the "Other ingredients" line, especially if you avoid certain fillers.
- Look for third-party quality seals. ODS names ConsumerLab.com, NSF International and U.S. Pharmacopeia, and notes these seals don't guarantee a product is safe or effective (ODS).
Our own label lists the form, the amount and the plant source. OPA Berberine Plus gives a 1,200 mg berberine HCl blend from Berberis aristata bark and root per two-capsule serving, with no caffeine. The full panel is on the product page.
OPA Berberine Plus (60 capsules, 30 servings): 1,200 mg berberine HCl blend from Berberis aristata bark and root per two-capsule serving. Caffeine-free, in hypromellose capsules. Contains berberine. Talk to your healthcare professional before use if you take any medication.
Frequently asked questions
What is the downside to berberine?
The two main downsides are stomach upset and medicine interactions. Digestive effects are common but usually mild. Interactions are less obvious because you can't feel them, so check with your pharmacist if you take any medicine.
What organ is berberine hard on?
No organ stands out in the human data. LiverTox has not linked berberine to liver injury, and short studies didn't find liver or kidney problems. The gut is where most side effects show up.
What should you not mix with berberine?
Don't combine it with other berberine-containing herbs such as goldenseal without checking the total. Ask your pharmacist about any medicine cleared by CYP3A4, CYP2D6 or CYP2C9, and about cyclosporine in particular.
Can you drink alcohol while taking berberine?
We couldn't find human studies on berberine and alcohol together. Berberine does affect liver enzymes, so if you drink regularly, ask your healthcare professional before starting.
Why are some doctors cautious about berberine?
NCCIH points out that the amounts and forms of berberine used in studies vary widely, many studies had a high risk of bias, and most studies on weight and heart-risk factors were done in Asian countries. Add the interaction risk, and caution makes sense.
Can women take berberine?
Yes, adult women can, with one big exception: don't use it if you're pregnant, trying to get pregnant or breastfeeding. Talk with your healthcare professional first.
Sources
- National Center for Complementary and Integrative Health (NCCIH). Berberine and Weight Loss: What You Need To Know. Updated November 2023.
- NCCIH. Diabetes and Dietary Supplements: What You Need To Know (Berberine section). Updated November 2023.
- NCCIH. Goldenseal. Updated February 2025.
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Berberine. NIH (NIDDK). 2020.
- Guo Y, Chen Y, Tan ZR, Klaassen CD, Zhou HH. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol. 2012.
- Wu X, Li Q, Xin H, Yu A, Zhong M. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol. 2005.
- Yin J, Xing H, Ye J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism. 2008.
- Ju J, Li J, Lin Q, Xu H. Efficacy and safety of berberine for dyslipidaemias: a systematic review and meta-analysis of randomized clinical trials. Phytomedicine. 2018.
- Li Z, Wang Y, Xu Q, et al. Berberine and health outcomes: an umbrella review. Phytother Res. 2023.
- Chan E. Displacement of bilirubin from albumin by berberine. Biol Neonate. 1993.
- U.S. Food and Drug Administration. Mixing Medications and Dietary Supplements Can Endanger Your Health.
- U.S. Food and Drug Administration. How to Report a Problem with Dietary Supplements.
- NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know.
Disclosure: OPA Nutrition sells supplements, including products mentioned in this article. This content is for education only and is not medical advice. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your healthcare provider before using any supplement, especially if you take medication or have a medical condition.
