Berberine is generally considered safe for most people and is on the shelf of most retailers selling supplements.
The problem I have with berberine is (N=1) that I did not find it effective at the recommended doses and I did experience some of the side effects.
The studies of berberine are not very convincing so I dropped it from my supplement list.
Common Side Effects
Gastrointestinal Issues:
Nausea: Some individuals may experience nausea when taking berberine.
Diarrhea: Diarrhea is a common side effect, especially at higher doses.
Constipation: Conversely, some people may experience constipation.
Abdominal Pain and Cramping: Berberine can cause abdominal discomfort and cramping in some individuals.
Bloating and Gas: Gastrointestinal bloating and gas are also reported.
Less Common Side Effects
Hypotension: Berberine may lower blood pressure, which can be problematic for individuals with already low blood pressure or those taking antihypertensive medications.
Serious Side Effects
Liver Toxicity:
Hepatotoxicity: While rare, there have been reports of liver toxicity associated with berberine supplementation, particularly at high doses or with prolonged use. Symptoms can include elevated liver enzymes and jaundice.
Interactions with Medications:
Cytochrome P450 Enzymes: Berberine can inhibit certain cytochrome P450 enzymes (CYP3A4, CYP2D6, CYP2C9), which are involved in drug metabolism. This can lead to interactions with various medications, potentially increasing their effects or side effects.
Anticoagulants: Berberine may enhance the effects of blood-thinning medications, increasing the risk of bleeding.
Antidiabetic Medications: Berberine can enhance the effects of antidiabetic medications, potentially leading to hypoglycemia (low blood sugar).
Vitamin B12 Absorption:
Reduced Absorption: Some studies suggest that berberine may reduce the absorption of vitamin B12, which can lead to deficiencies over time.