Hamamelis virginiana (also known as witch hazel) is a commonly used plant extract that may have potent antioxidant properties and some sedative properties. However, this ingredient's high tannin content (tannin is a potent antioxidant) can also make it sensitizing if used repeatedly on the skin because it denatures proteins that help keep the skin healthy.
The bark of the Hamamelis virginiana plant has a higher tannin content than the leaves, which contain other compounds, including beneficial antioxidants. Making witch hazel by steam distillation removes the tannins and can bypass the need to use skin-damaging alcohol (ethanol), but the plant's astringent properties are what most people believe gives it its benefit. However, using water or steam distillation rather than alcohol is a way to obtain a milder form of this ingredient for occasional use; it just doesn't make witch hazel problem-free, so we advise against using it on the skin often. https://www.paulaschoice.com/ingredient-dictionary/ingredient-hamamelis-virginiana.html?q=Hamamelis%20Virginiana%20Leaf%20Extract&fdid=ingredients