Which ingredient is commonly recognized as an astringent?

Witch hazel is commonly recognized as an astringent due to its high tannin content. Astringents are substances that can help tighten or constrict body tissues, which is particularly beneficial in skincare. They work by removing excess oil and can help reduce inflammation, making them effective for managing oily skin and acne. Witch hazel is often used in toners and other skincare products for its ability to cleanse the skin and minimize the appearance of pores.

Rosewater, while soothing and hydrating, does not have the strong astringent properties that witch hazel does. Tea tree oil has antiseptic and antibacterial properties, making it effective for treating acne, but it is not primarily classified as an astringent. Glycerin is a humectant, meaning it attracts moisture to the skin, and is used primarily for its moisturizing properties, rather than for astringency. Thus, the distinct ability of witch hazel to tighten skin and reduce oiliness firmly categorizes it as the correct answer regarding commonly recognized astringent ingredients.