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Gld3.5
Goldenseal Research
Mostly mechanism / observational
9 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
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 9 studies · 5 RCTs
Confidence
Moderate confidence
By outcome
Glucose & metabolic
Too few graded studies1 study
Safety profile
Too few graded studies1 study
Active research area
4 studies in the last 5 years
200520152025
1Review2024
In plain English: By exploring these emerging mechanisms, we aim to broaden the scope of natural product-drug interaction research and encourage comprehensive studies to better elucidate complex mechanisms.
Oyanna VO, Clarke JD. · Drug metabolism reviews (2024)
Applying the Biopharmaceutics Drug Disposition Classification System (BDDCS) can serve as a framework for predicting and understanding these interactions.
This understanding is vital for healthcare professionals to effectively anticipate and manage potential natural product-drug interactions, ensuring optimal patient therapeutic outcomes.
By exploring these emerging mechanisms, we aim to broaden the scope of natural product-drug interaction research and encourage comprehensive studies to better elucidate complex mechanisms.
Approximately 9% of Europeans and white Americans are either poor CYP2D6 metabolizers or poor OCT1 transporters.
Common OCT1 alleles *3 to *6 showed uptake reduced by at least 65% and Oct1/2 knockout mice showed 3.2-fold higher AUCs in liver perfusion experiments.
Females who were poor CYP2D6 metabolizers had an 80% lower M1-to-berberine ratio.
In plain English: Comparisons of pre- and post-supplementation MDZ pharmacokinetic parameters revealed significant inhibition of CYP3A by goldenseal... These findings suggest that significant herb-drug interactions may result from the concomitant ingestion of goldenseal and CYP3A substrates.
Gurley BJ et al. · Clinical pharmacology and therapeutics (2008)
Goldenseal significantly inhibited CYP3A (midazolam probe) in 16 healthy volunteers
Significant herb-drug interaction potential with CYP3A substrates
In plain English: Botanical supplements containing goldenseal strongly inhibited CYP2D6 and CYP3A4/5 activity in vivo... serious adverse interactions may result from the concomitant ingestion of goldenseal supplements and drugs that are CYP2D6 and CYP3A4/5 substrates.
Gurley BJ et al. · Clinical pharmacology and therapeutics (2005)
Goldenseal strongly inhibited CYP2D6 and CYP3A4/5 (~40%) in vivo
Serious adverse interaction potential with CYP2D6/CYP3A4 substrates
In plain English: supplementation with these specific formulations of goldenseal or kava kava did not appear to affect digoxin pharmacokinetics, suggesting that these supplements are not potent modulators of P-gp in vivo
Gurley BJ et al. · Drug metabolism and disposition: the biological fate of chemicals (2007)
Goldenseal did NOT significantly alter digoxin (P-glycoprotein substrate) pharmacokinetics
Not a potent P-gp modulator in vivo (distinct from its CYP effects)
In plain English: The aggregate pharmacokinetic data indicated no clinically meaningful interaction... However, metformin AUC decreased by ~20%, 14%, and 0% after goldenseal coadministration at low, moderate, and high metformin doses, respectively
Nguyen JT et al. · Clinical and translational science (2025)
No clinically meaningful overall interaction (metformin AUC GMR within no-effect range)
Dose-dependent decrease in metformin exposure (~20% at low metformin doses)
Open-label crossover in adults with type 2 diabetes
In plain English: goldenseal increased the area under the plasma concentration-time curve (AUC0-inf ) of midazolam (CYP3A; positive control)... decreased metformin (OCT1/2, MATE1/2-K) AUC0-inf (GMR, 0.77 (0.71-0.83))
Nguyen JT et al. · Clinical pharmacology and therapeutics (2021)
In plain English: Investigators studied four different herbal medicines (St John's wort, garlic, goldenseal and milk thistle) and one vitamin (vitamin C). Significant interactions were observed with St John's wort, garlic and vitamin C.
Mills E et al. · International journal of STD & AIDS (2005)
Reviewed goldenseal among natural products studied for HIV-drug interactions
Significant interactions were seen with St John's wort, garlic and vitamin C (not goldenseal specifically)
Methodological limits noted; further research urged