Common Name(s): Provitamin d3,delta-7-cholesterol

CAS Number: 434-16-2

DESCRIPTION

What It Does: Serves as the skin's natural starting material for vitamin d3 production upon uvb exposure.

Why It's Used: Formulations supporting the skin's endogenous vitamin d synthesis pathway, particularly relevant when spf blocks uvb.

How It Works: Absorbs uvb (290–315 nm) and undergoes photolysis at the b-ring to form previtamin d3, which thermally isomerizes to cholecalciferol at body temperature.

Typically Found In: Specialty skin health formulations

TECHNICAL DETAILS

Primary Category: Active ingredient – provitamin d3

Secondary Functions: Provitamin d3,endogenous synthesis support

Application Areas:

Typical Concentration Range: Research/specialty concentrations

SOURCING & ETHICS

Vegan Status: Conditional – lanolin or synthetic

Halal Status: Conditional – verify source

Source Notes: Lanolin-derived or lichen-derived (vegan). verify source.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating at cosmetic concentrations.

Safe for Sensitive Skin: Yes at cosmetic concentrations

SAFETY & COMPATIBILITY

Safety Profile: Safe at cosmetic concentrations. ewg score: 1.

Works Well With: Ceramides,retinoids,anti-inflammatory actives

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Approximately 90% of body vitamin d3 comes from uvb-induced photosynthesis of 7-dehydrocholesterol in skin. high-spf sunscreen reduces this synthesis by 95–99%.

Last Verified: Cosing database,holick vitamin d cutaneous synthesis review

Primary Sources: 2026-03-12