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Reviewed by the Scan Dose Research Team and Clinical Advisory Board

Berberine

STRONG EVIDENCEBotanicalLast updated April 5, 2026

SCAN DOSE SUMMARY

Berberine is a plant alkaloid with blood-sugar-lowering potency that rivals some prescription diabetes medications. Our research, from 6 RCTs, 12 meta-analyses, and 33,646 participants, shows strong evidence for reducing blood glucose, HbA1c, total cholesterol, and triglycerides — particularly in type 2 diabetes and PCOS. It's a serious bioactive compound, not a casual supplement. The key safety issue: it inhibits CYP3A4, CYP2D6, and CYP2C9 enzymes, creating drug interactions with a huge range of medications.

EVIDENCE GRADES

Total CholesterolStrong
A
Blood Glucose (T2D)Large improvement
B
HbA1c (T2D)Large improvement
B
TriglyceridesModerate
B
LDL CholesterolModerate
B
Blood PressureModerate
B
Insulin ResistanceModerate
B

OPTIMAL DOSAGE

  • Standard dose: 900-2,000mg/day, divided into 3-4 doses
  • Take with meals (uses post-meal glucose spike)
  • Start low to reduce GI effects. Too much at once = stomach upset, diarrhea.
  • Bioavailability: Only ~5% absorbed. Enhanced formulations (liposomal, micelle) increase absorption 6x+ but also amplify drug interactions.
Scan a supplement containing Berberine

DRUG INTERACTIONS

CYP3A4 substrate drugs (statins, CCBs, HIV meds, many others)Severe

Increases drug levels

Monitor drug levels. Genetic susceptibility varies.

CYP2D6 substrate drugs (metoprolol, fluoxetine, codeine)Moderate

Increases drug levels

Monitor.

BP-lowering drugsModerate

Additive BP reduction

Monitor BP.

Blood-glucose-lowering drugsMinor

Additive glucose reduction

Monitor blood glucose.

CYP2C9 substrates (warfarin, phenytoin)Unknown

May increase drug levels

Monitor if combining.

Blood thinnersUnknown

Theoretical bleeding risk

Unlikely clinically significant.

SAFETY PROFILE

Side Effects

  • Very common: Stomach pain, nausea, vomiting, diarrhea, constipation, flatulence
  • Less common: Dizziness, drowsiness, fatigue, headache

Drug Interactions

Precautions

  • Pregnancy: AVOID. Can initiate uterine contractions (miscarriage risk). May cause bilirubin toxicity in infants (jaundice, kernicterus).
  • Breastfeeding: AVOID. Passes into breast milk. Same bilirubin toxicity concerns.
  • Diabetes: Monitor closely — additive blood sugar reduction. Not a substitute for medical care.
  • Enhanced-bioavailability formulations: Amplify both effects AND drug interactions. Use with extra caution.

Quality Concerns

Studies in US and France found berberine supplements frequently don't contain labeled amounts. Third-party testing recommended.

WADA Status

Not Prohibited.

WHO SHOULD BE CAREFUL

QUALITY CONCERNS

Studies in US and France found berberine supplements frequently don't contain labeled amounts. Third-party testing recommended.

HOW SCAN DOSE SCORES THIS

Present at 500-1,500mg:✅ Green flag for metabolic health — strong evidence base
In someone on diabetes medications:⚠️ Yellow flag — additive glucose-lowering, needs monitoring
In someone on CYP3A4 medications (statins, etc.):🔴 Red flag — documented toxic drug level increases
During pregnancy:🔴 Red flag — contraindicated
Enhanced bioavailability form + medications:🔴 Red flag — amplified interaction risk

RELATED RESEARCH

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Scan Your Berberine SupplementBrowse all ingredients

Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated: April 5, 2026

Not medical advice. Based on published clinical research and systematic reviews.

Safety

Berberine: Drug Interactions

Do not combine

Dangerous interactions. Talk to your prescriber before using this supplement if you take any of these.

  • Metformin

    Berberine and metformin lower blood glucose via similar pathways.

    RiskSevere hypoglycemia.
    ActionStart at 500mg berberine. Monitor glucose closely. Metformin dose may need to be reduced.

    Source: PMID: 37439907

  • Cyclosporine

    Berberine inhibits CYP3A4 and P-glycoprotein, dramatically increasing cyclosporine levels.

    RiskCyclosporine toxicity (nephrotoxic).
    ActionNever combine without transplant team supervision.

    Source: Clinical pharmacology

Use with caution

Moderate interactions. Monitoring, timing separation, or dose adjustment may be required.

  • CYP2D6 substrates (codeine, tramadol, many antidepressants)

    Berberine inhibits CYP2D6.

    RiskIncreased drug levels.
    ActionMonitor for side effects.

    Source: PMID: 38928095

  • CYP3A4 substrates (statins, calcium channel blockers)

    Berberine inhibits CYP3A4.

    RiskIncreased drug levels and potential toxicity.
    ActionUse caution with narrow-therapeutic-index drugs.

    Source: PMID: 37439907

  • Sulfonylureas (glipizide, glyburide)

    Additive glucose lowering.

    RiskHypoglycemia.
    ActionMonitor blood sugar closely.

    Source: Clinical consensus

  • Blood pressure medications

    Berberine may lower BP.

    RiskHypotension.
    ActionMonitor BP.

    Source: Clinical consensus

  • Anticoagulants

    Berberine may have antiplatelet effects.

    RiskBleeding risk.
    ActionMonitor if combining.

    Source: Limited evidence

Educational information only. This is not medical advice. These statements have not been evaluated by the FDA. Talk to your prescriber before starting, stopping, or combining any supplement with prescription medication.

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