Does Grapefruit Affect Goldenseal?

Amount or timing may matter

The short answer

Goldenseal (hydrastine, berberine) is a potent CYP3A4 inhibitor. Combined with grapefruit, additive CYP3A4 inhibition may dangerously alter metabolism of co-administered supplements.

How to arrange timing

Avoid combining goldenseal with grapefruit if you take other CYP3A4-metabolized supplements.

Reference

Reference noted for this food and supplement combination: Gurley et al., Clin Pharmacol Ther 2005

Important context

The effect can also change with food amount, supplement dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.