Black walnut hull extract comes from the green hulls of the black walnut tree. It contains juglone and tannins, compounds that give the hulls astringent properties.
People take the extract as part of a digestive wellness routine, often as a tea, tincture, or capsule. Traditional use focuses on gut health, though solid scientific evidence is sparse.
Take black walnut hull extract with food to reduce the chance of stomach upset. Doses and forms differ widely, so stick to the label instructions.
Key cautions: The extract can trigger allergic reactions in anyone with a tree nut allergy. Avoid it during pregnancy and while breastfeeding. Large doses may irritate the stomach and intestines.