Sunday Riley's Good Genes All-In-One Lactic Acid Treatment is a popular serum that uses high-potency lactic acid (an AHA) to deeply exfoliate, clarify, and brighten skin, revealing instant radiance, smoothness, and plumper-looking fine lines, while also tackling dark spots and congestion with ingredients like licorice and lemongrass, making it suitable for all skin types for daily or mask use.