Sodium Ascorbyl Phosphate (SAP)1
Stay-C® 50
Vitamin C Derivative
Stability
9/10
Excellent
Irritation Risk
Low
for most skin types
Bioavailability
6/10
skin absorption
pH Needed
pH 5.5–7.0
for efficacy
What Is It?
The dermatologist's choice for acne-prone skin. SAP has an added antibacterial property that makes it unique among Vitamin C derivatives — it actually helps fight Cutibacterium acnes (the acne-causing bacteria) while brightening skin simultaneously.
🔬 The Science
SAP is converted to LAA by phosphatase enzymes in the skin. Its antibacterial mechanism works via photo-excitation — when exposed to light, SAP generates reactive oxygen species that destroy bacterial cell membranes.
⚗️ Stability Note
Very stable in aqueous formula. The sodium salt form prevents oxidation at neutral pH levels.
Optimal Concentration
Available Range
5%–15%
Our Recommendation
10%–15%
Best For
- Acne-Prone Skin
- Oily Skin
- Sensitive Skin
- Anti-bacterial benefit
Avoid If
- Those seeking maximum anti-aging efficacy