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Goldenseal (Hydrastis canadensis; berberine/hydrastine)
A traditional immune/antimicrobial herb whose most important real-world property is potent drug-interaction risk (CYP3A4/2D6 inhibition); efficacy evidence is weak.
What the evidence says
Most Goldenseal studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from medium-quality randomised trials published 2005–2025.
Based on 7 studies · 4 RCTs
Confidence
ModerateBy outcome
Goldenseal has an evidence score of 3.5/10 — emerging evidence based on 7 indexed studies. A traditional immune/antimicrobial herb whose most important real-world property is potent drug-interaction risk (CYP3A4/2D6 inhibition); efficacy evidence is weak. Representative study: PMID 22855269.
The commonly studied dose of Goldenseal is Traditional: 0.5-1g root (or ~250-500mg extract) up to 3x daily, short-term — but weigh against significant drug-interaction risk. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
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Last reviewed June 2026 · evidence from 7 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Goldenseal (Hydrastis canadensis) is a traditional North American herb containing berberine and hydrastine, marketed for immune support, colds, and digestive/mucosal health. Honestly, the human efficacy evidence for those uses is weak. What goldenseal IS well-documented for is being one of the most potent botanical inhibitors of the drug-metabolizing enzymes CYP3A4 and CYP2D6 — meaning it can dangerously raise blood levels of many medications. This card exists mainly so that interaction is visible: treat goldenseal as a use-with-caution herb, not a casual immune supplement.
Strongly inhibits CYP3A4 and CYP2D6, slowing the metabolism of many drugs (the dominant, well-documented effect).
Contains berberine, which has antimicrobial activity in the lab.
Traditionally used as an astringent on mucous membranes.
Traditional: 0.5-1g root (or ~250-500mg extract) up to 3x daily, short-term — but weigh against significant drug-interaction risk
Take with food
| Form | Type |
|---|---|
| 💊Root extract (short-term, with interaction caution) | Recommended |
| 💧Tincture | Alternative |
| 💊Capsule | Alternative |
The drug-interaction risk usually outweighs the weak efficacy evidence.
Minimum: 1 weeks
Optimal: 2 weeks
Cycling: Short courses only; not for ongoing daily use, partly because of cumulative interaction risk.
Note: Short-term with food; avoid alongside affected medications.
Dose-response data unavailable. The current published research for Goldenseal does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Inhibits CYP3A4/2D6, raising levels of many medications — the most important effect to know.
Used for colds/immune support, but human efficacy evidence is weak.
Avoid unless cleared by a pharmacist/clinician — high CYP drug-interaction risk.
Avoid — berberine can cross the placenta and displace bilirubin (kernicterus risk).
Avoid.
Goldenseal strongly inhibits CYP3A4 — can raise drug levels to toxic ranges.
Inhibits CYP2D6 — altered drug levels and effects.
Alters transporter-mediated drug pharmacokinetics.
Tip: Take with food; short courses
Tip: Avoid if hypertensive
Tip: Reduce dose
The best time to take Goldenseal is with meals. Taking it with food is preferred. Taken with food short-term; most importantly, separate from and avoid with medications affected by CYP3A4/2D6.
Goldenseal should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are GI upset, raised blood pressure, mucosal irritation. Use caution if any of these apply to you: Concurrent use of any CYP3A4 or CYP2D6-metabolized medication; Pregnancy and breastfeeding (berberine crosses placenta; risk of kernicterus in newborns); Hypertension.
Reduces cold risk and shortens infection duration — most effective when started at first sign of symptoms.
CYP inhibition can dangerously alter HIV drug levels.