What are the tannins in oak bark and how do they act on mucous membranes and skin? — Oak bark herbal tea, 50 g - Norden Natur

Tannins are polyphenolic compounds that can bind proteins. On contact with a mucous membrane or the skin they settle on the surface and form a thin, insoluble pellicle. This film mechanically protects the nerve endings from irritants (acids, enzymes, bacterial toxins, friction), reduces swelling by constricting the blood vessels and temporarily lowers the permeability of the tissues. In practice it feels like an astringent, "dry" sensation in the mouth and a reduced sensitivity to pain in inflamed areas. The antioxidant activity of tannins lies in their ability to bind free radicals, which may help restore the integrity of the barrier. It is important to understand that the effect is local and reversible — the protective layer is washed away within a few hours. The product is a herbal tea for drinking; the label gives no instructions to use it on the skin or for gargling. With prolonged, frequent use, constipation or nausea may occur because of the astringent effect on the intestines — in that case reduce the dose or take a break.