Common Name(s): Pyrrolidine-2-carboxylic acid,l-proline
CAS Number: 147-85-3
DESCRIPTION
What It Does: Provides hydroxyproline precursor collagen support and osmoprotective nmf conditioning.
Why It's Used: The collagen imino acid โ proline and its hydroxylated form hydroxyproline comprise approximately 25% of all collagen amino acids, making l-proline the essential structural amino acid for topical collagen support.
How It Works: Hydroxylated by prolyl hydroxylase (requires vitamin c) to form hydroxyproline โ essential for collagen triple-helix stability. nmf osmoprotective function via pyrrolidine ring water interaction. proline-rich repeats in collagen provide gly-pro-hyp triple-helix structure.
Typically Found In: Collagen-support products,nmf moisturisers,anti-aging formulas
TECHNICAL DETAILS
Primary Category: Active ingredient โ collagen amino acid
Secondary Functions: Skin conditioning
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.5%โ5%
SOURCING & ETHICS
Vegan Status: Yes โ fermentation
Halal Status: Yes
Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Well-tolerated by most skin types.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Good safety profile at recommended concentrations. ewg score: 1โ2.
Works Well With: Standard skincare actives
Avoid Combining With: No known significant incompatibilities
SCIENTIFIC NOTE
Proline's prolyl hydroxylase conversion to hydroxyproline is completely vitamin c-dependent: the hydroxylase enzyme requires ascorbate as cofactor. this biochemical interdependence explains why vitamin c deficiency (scurvy) produces defective collagen โ hydroxyproline cannot form without vitamin c, and without hydroxyproline the collagen triple helix cannot maintain its structure at body temperature, causing tissue fragility.
Last Verified: Cosing database,cir safety assessment
Primary Sources: 2026-03-12