Proline

An amino acid that plays a role in collagen synthesis and skin hydration. Proline is a crucial amino acid that functions as a component of the skin's Natural Moisturizing Factor (NMF), where it contributes to water binding within the stratum corneum, thereby enhancing hydration and barrier function. It also serves as a vital precursor for collagen synthesis by dermal fibroblasts, supporting the structural integrity, firmness, and elasticity of the skin.

Proline is generally considered safe for topical use in cosmetic formulations. The Cosmetic Ingredient Review (CIR) Expert Panel has reviewed amino acids, including proline, and found them safe for use in cosmetics with low potential for irritation or sensitization.

Look for products with 0.5-5% (often used as part of amino acid blends or NMF-mimicking complexes in various cosmetic formulations). for clinical efficacy.