Serine(1,300 Ppm)
Serine is a non-essential amino acid, meaning the body can synthesize it on its own. In cosmetic formulations it most commonly appears as part of a moisturizing complex, functioning as a water-binding (humectant) ingredient. It is considered a skin-identical ingredient, as amino acids are naturally present in the skin's Natural Moisturizing Factor (NMF). There is limited specific research on serine's isolated effects on skin compared to amino acids as a broader class.
Serine contributes to skin hydration by binding water in the stratum corneum, supporting the skin's natural moisture levels. As an amino acid found in the skin's NMF, it plays a role in maintaining proper skin hydration. Evidence for its specific benefits is limited, with most support coming from research on amino acids generally rather than serine in isolation.
