The ingredient, explained

Hydroxyproline

Laboratory research tested free L-hydroxyproline in skin fibroblasts.

AntistaticHair conditioningSkin conditioningSurfactant

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Ingredient guide

What it is and what it does

L-4-hydroxyproline

About this ingredient: EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗

Antistatic: Reduces the build-up of static electrical charge on surfaces.
Hair conditioning: Improves cosmetic hair properties such as softness, shine or combability.
Skin conditioning: A broad cosmetic role for maintaining skin condition. It does not identify a particular clinical benefit.
Surfactant: Changes surface tension to help a product distribute or interact with other materials.

Function definitions: European Commission ingredient function definitions (SCCNFP/0299/00, pages 16 to 20) ↗

Registry functions describe possible formulation roles, not results for a finished product. A dictionary entry is not an approval or a safety assessment.

A closer look

What the research shows

Laboratory research

Collagen-gene responses varied by collagen type and electrical stimulation.

What this does not tell us

Cell and gene-expression findings do not establish clinical skin rejuvenation.

Sources for this summary. PubMed 38304625 ↗

Research review checked Oct 1, 2026

Read exact local candidate abstracts first; select identity-relevant papers; targeted primary PubMed/publisher searches. This is not an exhaustive systematic review.

Ingredient research is not proof that a product containing this ingredient works.