Yogurt acts as a natural chemical exfoliant because its lactic acid dissolves the 'glue' holding dead skin cells together.

Lactic acid belongs to the Alpha Hydroxy Acid (AHA) family and is naturally produced during the fermentation of milk by Lactobacillus bacteria. In skincare, it serves as a keratolytic agent, meaning it breaks down the desmosomes—the protein structures that act like glue to bind skin cells together. By weakening these bonds, lactic acid promotes the shedding of the stratum corneum, which is the outermost layer of the epidermis.Historical records suggest that Cleopatra famously bathed in sour milk to maintain her complexion, a practice that utilized these same chemical properties long before modern dermatology. Today, clinical studies published in the Journal of the American Academy of Dermatology confirm that AHAs like lactic acid improve skin texture and reduce hyperpigmentation. Unlike glycolic acid, which has a smaller molecular size and can penetrate deeper, lactic acid has a larger molecular structure that remains on the surface. This makes it significantly less irritating and more suitable for people with sensitive skin types.Beyond exfoliation, yogurt contains zinc and B vitamins which support cellular regeneration and reduce inflammation. The lipid content in full-fat yogurt also helps repair the skin's natural moisture barrier, preventing the trans-epidermal water loss often associated with chemical treatments. This dual action of exfoliating while moisturizing is why lactic acid remains a primary ingredient in professional-grade skincare products today.