Sodium Ascorbyl Phosphate (SAP) is a stable, water-soluble Vitamin C derivative. It is gentler than L-Ascorbic Acid and has demonstrated antimicrobial activity against C. acnes bacteria, making it a dual-purpose ingredient for brightening and acne-prone skin.
Key Skin Benefits
+ Stable Vitamin C derivative (no rapid oxidation)
+ Brightens skin tone and reduces hyperpigmentation
+ Demonstrated anti-acne activity against C. acnes
+ Stimulates collagen synthesis
+ Gentle — suitable for sensitive skin
Pros
+ Stable in water-based formulations at pH 5-7
+ Anti-acne properties make it unique among Vitamin C forms
+ Non-irritating at effective concentrations
+ Can be used in clear, water-based serums
+ Good for sensitive/acne-prone skin types
Cons
− Requires enzymatic conversion to active Vitamin C
− Less potent antioxidant than L-Ascorbic Acid
− Conversion efficiency may vary by individual
− Higher cost per unit of activity than L-AA
Specifications
Property
Value
Usage Areas
Face, Eye, Body
Product Type
Leave-On, Rinse-Off
Source
Synthetic
Natural Level
Synthetic
Safety Ratings
Metric
Rating
Skin Sensitivity
1/5 (very low)
Comedogenic Rating
0/5
EWG Score
1/10
Regional Regulatory Limits
Region
Leave-on %
Rinse-off %
Status
EU (CosIng)
No limit
No limit
Allowed
US (CIR/FDA)
No limit
No limit
Allowed
Japan (MHLW)
No limit
No limit
Allowed
ASEAN
No limit
No limit
Allowed
China (NMPA)
No limit
No limit
Allowed
Typical Usage % by Product Type
Product Type
Typical %
Vitamin C serum
1 - 5%
Acne treatment
1 - 3%
Brightening cream
0.5 - 2%
References
Klock J et al. (2005) — SAP against C. acnes. PMID: 16185284
Campos PM et al. (2009) — Vitamin C derivatives in skin. PMID: 19330105