Understanding STAY-C® 50: A Stable and Powerful Vitamin C Derivative
STAY-C® 50 (INCI: Sodium Ascorbyl Phosphate) is a stable, water-soluble derivative of vitamin C designed for high efficacy in topical applications. Unlike traditional ascorbic acid, which is notoriously unstable and prone to oxidation, STAY-C® 50 retains potency and efficacy in formulations over time.
This monophosphate ester of ascorbic acid is bio-converted into active vitamin C (ascorbic acid) by enzymes in the skin, delivering benefits without the instability of pure vitamin C.
Key Skincare Benefits of STAY-C® 50
- Photoprotection: STAY-C® 50 reduces reactive oxygen species (ROS) caused by UV exposure, complementing UV filters like PARSOL® [1].
- Improved skin firmness: Stimulates collagen I and III synthesis, resulting in firmer, more resilient skin [2].
- Brightening and evening of skin tone: Reduces melanin production and visibly fades age spots by up to 25% after 12 weeks [3].
- Anti-acne action: Reduces acne-related bacteria and sebum oxidation, with clinical data showing it outperforms benzoyl peroxide in one 12-week study [4].
Comparison With Other Vitamin C Derivatives
Vitamin C serums can feature various derivatives including:
- Ascorbic Acid: Highly active but unstable; requires low pH and often causes irritation.
- Magnesium Ascorbyl Phosphate (MAP): Gentle and moisturising but with limited penetration and clinical evidence.
- Tetrahexyldecyl Ascorbate (THD): Lipid-soluble and suitable for deeper penetration, but more costly and not as extensively studied in public literature.
- STAY-C® 50: Balances stability, bioavailability, and demonstrated efficacy across multiple skin concerns with several published studies available.
While STAY-C® 50 is backed by clinical data from dermatological and in vitro studies, most of this research has been sponsored or supported by its manufacturer. However, these findings are still valuable and publicly available—more so than for many other newer vitamin C derivatives.
Formulation and Usage Considerations
STAY-C® 50 is ideally used at concentrations between 0.5–5.0%. It should be formulated at around pH 7 and added at temperatures below 40°C to ensure stability. It’s suitable for emulsions, gels, lotions, sprays and stick formats across skincare, haircare and oral care.
Scientific Backing
STAY-C® 50 is supported by clinical and in vitro studies showing benefits for skin tone, firmness, antioxidant protection and acne reduction. Most of this research is accessible via peer-reviewed journals or manufacturer technical literature:
STAY-C® 50 is a scientifically supported, stable vitamin C derivative offering broad-spectrum skin benefits—from brightening and firming to antioxidant defence and acne care. While most of its supporting studies are manufacturer-sponsored, they are publicly accessible and show meaningful results that help it stand out in the crowded vitamin C market.
