Commonly used plant extract that can have potent antioxidant properties and some anti-irritant properties. However, witch hazel’s high tannin content (tannin is a potent antioxidant) can also make it irritating if used repeatedly on skin because it constricts blood flow. The bark of the witch hazel plant has a higher tannin content than the leaves. Producing witch hazel water by steam distillation removes the tannins, but the plant’s astringent qualities are what most believe give it benefit. [1, 2, 3]
Alcohol is added during the distillation process, the amount typically being 14–15%.  Witch hazel water is distilled from all parts of the plant; therefore, you never know exactly what you’re getting, although the alcohol content remains.
Depending on the form of witch hazel, you’re exposing your skin either to an irritating amount of alcohol (which causes free-radical damage and collagen breakdown) or to tannins, or both. Moreover, witch hazel contains the fragrance chemical eugenol, which is another source of irritation. 
- Hughes-Formella B, Filbry A, Gassmueller J, Rippke F. Anti-inflammatory efficacy of topical preparations with 10% hamamelis distillate in a UV erythema test. Skin Pharmacol Appl Skin Physiol. 2002;15(2):125-32.
- Choi H, Choi J, Han Y, Bae S, Chung H. Peroxynitrite scavenging activity of herb extracts. Phytother Res. 2002;16(4):364-7.
- Masaki H, Atsumi T, Sakurai H. Protective activity of hamamelitannin on cell damage of murine skin fibroblasts induced by UVB irradiation. J Dermatol Sci.. 1995;10(1):25-34.
- Thring T, Hili P, Naughton D. Antioxidant and potential anti-inflammatory activity of extracts and formulations of white tea; rose; and witch hazel on primary human dermal fibroblast cells. J Inflamm (Lond).. 2011;8:27.
- Trüeb R. North American Virginian Witch Hazel (Hamamelis virginiana): Based Scalp Care and Protection for Sensitive Scalp; Red Scalp; and Scalp Burn-Out. Int J Trichology. 2014;6(3):100-103.