Witch hazel is an extract of the bark and leaves of Hamamelis virginiana, a North American shrub. It has one of the longest continuous histories of any topical botanical, and one of the most misunderstood ingredient profiles.
How it works
Witch hazel's astringency comes from tannins, chiefly hamamelitannin. Tannins bind and precipitate proteins, which causes tissue at the surface to contract temporarily. That is the tightening sensation, and the reason witch hazel appears in products aimed at the appearance of pores and at excess surface oil.
Tannins also have documented antioxidant and anti-inflammatory activity, so the effect is not purely mechanical.
The alcohol question
This is where most confusion sits. Traditional witch hazel distillate, the kind sold in pharmacies as a standalone product, is typically preserved with 14 to 15 percent alcohol. Witch hazel's reputation for being harsh and drying largely comes from that alcohol rather than from the plant.
Cosmetic witch hazel extract is a different material. It may be alcohol-free, and where it appears in an ingredient list alongside a separate alcohol entry, as it does here, the two are distinct.
A genuine caveat about distillation
Worth knowing: steam distillation is a common preparation method, and tannins are not volatile. Distilled witch hazel therefore contains little to no tannin, which is the very constituent responsible for the astringency. Extracts prepared by other methods retain them.
An ingredient list showing "Hamamelis virginiana extract" does not indicate which preparation was used, so the actual tannin content is unknown from the label alone.
In formulation
Used in toners, after-shave products and formulations for oily skin. The effect on pore appearance is temporary and cosmetic; witch hazel does not change pore size, it constricts surrounding tissue for a period after application.
