Berberin Simply Explained

1. What Is Berberine?

Berberine is a natural substance from plants, more precisely an alkaloid. Alkaloids are certain plant substances with often strong effects. Berberine is found mainly in the bark, in the roots and in the underground shoots of some barberry and Coptis species. It has long been used in traditional Chinese and Ayurvedic medicine. In studies, it is mostly examined as a salt or as a plant extract.

2. Where Is It Found, and What Is It Made From?

Berberine occurs in barberries, in Coptis species and in goldenseal, as well as in Phellodendron. The highest contents are in the root, in the underground shoot and in the bark, not in the fruits. It is obtained by dissolving it out of root, underground shoot or bark. In studies and in commerce, it is mostly present as a salt, for example as hydrochloride or sulfate. Pure substance, plant extracts and combinations with substances intended to alter absorption are examined.

3. What Does Berberine Do? What Research Shows

Blood Sugar and Insulin

In diabetes and similar metabolic disorders, fasting sugar fell more in summary evaluations than in the comparison groups 11142023. The long-term blood sugar value also improved in such evaluations and in a study with sham treatment in prediabetes 111436. Several studies also showed better values for insulin action 11142336. Part of the results comes from combination preparations with other substances; these results apply to the mixture, not to berberine alone 41213. The informative value is high, but forms, amounts and population groups are inconsistent, and most studies lasted only a few months.

Blood Lipids

Several summary analyses show that blood lipids change more favorably with berberine and barberry preparations than in the comparison groups 114162023. In a large study with sham treatment (placebo), certain blood lipid levels also fell more than with placebo 24. The “good” HDL cholesterol improved in some summary analyses 2223, but remained unchanged in others 1416172035; in one study in rheumatoid arthritis, it fell compared with placebo 34. The forms tested were different, and many studies do not state the exact form and amount. The strength of evidence is considered high, but the observation periods are mostly short.

Body Weight

Summary evaluations of studies with random group assignment found a decrease in body weight, body mass index and waist circumference with berberine compared with the comparison group 171920. No difference in weight or body mass index was found in an evaluation in diabetes and in a study in fatty liver 1135. In people with schizophrenia who took certain medications, weight and waist circumference increased more with barberry root extract than with placebo 38. Results on mixtures cannot be transferred to berberine alone.

Polycystic Ovary Syndrome

In polycystic ovary syndrome (a hormonal and metabolic disorder), a study with random group assignment compared berberine hydrochloride with metformin and myo-inositol. Certain hormone values improved in all groups, most markedly with berberine 39. The informative value is moderate: there are two summary evaluations and one study with a comparison group. However, the form examined is inconsistent and partly not specified in detail.

Blood Pressure

Several summary evaluations found no difference from the comparison group in blood pressure 14151720. In a study with sham treatment in fatty liver, the systolic pressure in a special vascular measurement fell compared with the baseline value; for vascular stiffness, no difference from placebo was shown 33. A study with barberry root extract in schizophrenia under certain medications also found no difference in blood pressure 38. A mixed preparation improved the vascular response; this finding belongs to the mixture 31. For an effect on blood pressure, the informative value is unclear, and forms and comparison groups differ greatly.

Gut Microbiome

In a summary evaluation on small intestinal bacterial overgrowth (an overgrowth of the small intestine with bacteria), berberine alone achieved the highest rank for eradication of the overgrowth in the uncomplicated form 6. A review of studies with random group assignment describes an altered gut flora with berberine in diabetes, elevated blood lipids, intestinal polyps, mental illnesses and Parkinson's disease 18. These changes were not consistently favorable. Neither paper names the form examined, and the underlying human studies are captured only through these reviews. Therefore, the informative value is unclear.

Tolerability and Interactions

Studies with random group assignment on oral berberine 2433 and on an extract from barberry root compared with metformin 32 found no accumulation of side effects. Serious adverse events as well as kidney or liver damage also did not occur with oral berberine 36. A study on a special preparation form showed no differences in liver and kidney values and in tolerability 37. For combination preparations with further components, studies found no differences in adverse events 25272829. The informative value is overall unclear: the studies are mostly small and short, and several concern combination preparations. Robust statements on rare or longer-term side effects and on interactions remain open.

Other Investigations

In a large study with sham treatment in fatty liver and overweight, berberine lowered an inflammation value in the blood, but not the fat content of the liver 24. A study in fatty liver found no difference in liver enzymes 35. In gum inflammation, dental plaque and gum bleeding improved with a mouth rinse with berberine, but likewise with the comparison rinses 30. A combination preparation with several substances also reduced inflammation values in impaired blood sugar 26. Results of the mixtures cannot be transferred to berberine alone.

4. How Was Berberine Taken in the Studies?

Mainly berberine salts such as berberine hydrochloride, berberine sulfate and berberine citrate as well as plant extracts from barberry bark, Coptis or goldenseal were examined. Some studies also used a modification of the substance or a special preparation form. Sometimes the pure substance was examined, sometimes combinations with substances intended to alter absorption. Absorption differs between these forms. Many studies do not name the exact form and amount.

5. Is Berberine Safe? Side Effects in the Studies

It is important which form was tested, because the body absorbs the forms to different degrees. For combination products, the whole mixture counts: its result is not proof of berberine alone. Possible interactions of berberine with medications are an open question for further studies. Results from animal and cell experiments are preliminary investigations and not proof in humans.

All details with tables and sources: full expert page on Berberine