Tetrandrine (CAS NO: 518-34-3) is an alkaloid extracted from Stephania tetrandra S. Moore, a traditional Chinese medicinal plant. Celebrated for its anti-inflammatory, anti-oxidative, and anti-allergic properties, it has emerged as a functional ingredient in cosmetics, particularly for sensitive and irritated skin. As a white crystalline powder, it exhibits good stability in aqueous and oil-in-water systems, making it suitable for formulating soothing creams, essences, and post-procedure care products.