Sodium Ascorbyl Phosphate
Water-soluble stable vitamin C derivative. Skin phosphatase releases active ascorbic acid. Active at pH 7 – does not require acidic pH.
Evidence by route
Topical application
Clinical studies confirm antimicrobial activity in acne (via C. acnes suppression) and brightening effect. Anti-aging evidence is weaker than for L-ascorbic acid. The advantage is formula stability and gentleness.
- Sodium L-ascorbyl-2-phosphate 5% lotion for the treatment of acne vulgaris: a randomized, double-blind, controlled trial. J Cosmet Dermatol. 2010;9(1):22-27.. PMID 20367669
How to read tiers A–F
- BLimited evidence. One RCT or several controlled studies with limitations
Tolerability and safety
- Working concentrations
- 1–5%
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Sensitive, Oily, Combination, Normal, Dry
Combinations with other ingredients
About this ingredient
Sodium Ascorbyl Phosphate (SAP) is a water-soluble stable vitamin C derivative. A phosphate ester of ascorbic acid with sodium salt. Active at pH 7 – does not require acidic pH, unlike free L-ascorbic acid which needs pH 3.5. Mechanism. Skin phosphatases cleave the phosphate group, releasing active ascorbic acid. Conversion is slow but allows vitamin C effect without irritation from low pH. Key feature is formula stability: SAP does not oxidize as fast as pure L-ascorbic acid. Where applied. Vitamin C serums and creams (1-5%), brightening products, acne products (SAP combines antioxidant effect with antimicrobial activity against Cutibacterium acnes), anti-aging formulas. In Spain in Sesderma C-Vit, ISDIN Isdinceutics, La Roche-Posay Pure Vitamin C. Evidence base. Klock 2005 showed 5% SAP is comparable to 10% L-ascorbic acid in skin antioxidant effect but better tolerated. Woolery-Lloyd 2010 (RCT, n=30, acne) showed 49% reduction in inflammatory papules over 12 weeks with 5% SAP. Evidence level – B/A. Vs L-ascorbic acid. SAP is milder, more stable, gives a more modest but real effect. L-ascorbic acid 10-20% at pH 3.5 is the 'gold standard' for antioxidant protection but irritates sensitive skin. SAP is the optimal choice for sensitive skin, beginners, and teens with acne. Safety. CIR confirmed SAP safety (Final Report 2005). Hypoallergenic, non-irritating, non-comedogenic. Well tolerated by sensitive skin and rosacea patients. Pregnancy and lactation – safe. A natural vitamin C derivative, no topical restrictions. One of the few vitamin C actives recommended during pregnancy.
Frequently asked questions
Is Sodium Ascorbyl Phosphate safe during pregnancy?
Sodium Ascorbyl Phosphate is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Sodium Ascorbyl Phosphate for?
Sodium Ascorbyl Phosphate suits: sensitive, oily, combination, normal, dry.
What is Sodium Ascorbyl Phosphate and what does it do in cosmetics?
Water-soluble stable vitamin C derivative.
What's the INCI name for Sodium Ascorbyl Phosphate?
The INCI name is Sodium Ascorbyl Phosphate. It may also appear as: SAP.
What concentration of Sodium Ascorbyl Phosphate is effective?
1–5%
See Sodium Ascorbyl Phosphate in a product composition right on the store page
The Evigrade extension adds an evidence panel to iHerb, Sephora, Druni and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
Similar in action
Explore by category
Ingredients in the same category
Tartaric Acid, Thiamidol, Tranexamic Acid, Undecylenoyl Phenylalanine, Ascorbic Acid Polypeptide, Cystoseira Tamariscifolia Extract, Kojic Acid, Niacinamide
Published: · updated: