Magnesium Ascorbyl Phosphate (MAP) is a water-soluble derivative of vitamin C developed to improve on the limitations of pure ascorbic acid, especially its instability and potential to cause irritation. MAP offers superior stability and gentler skin compatibility, making it a valuable option for cosmetic formulations [1].

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Formulation Advantages & Skin Benefits

Scientific evidence indicates several distinct advantages of MAP:

• Stability in Formulations: MAP demonstrates excellent stability in topical formulations. Its chemical modification protects against rapid oxidation, and it retains stability even in neutral pH conditions (pH 7), unlike ascorbic acid which requires low pH (~3.5) for activity [2].

• Gentler on Skin: MAP is significantly less irritating than L-ascorbic acid. Animal studies confirmed no irritation after topical application, even at high doses, and sensitization testing showed no allergic reactions [3]. Its compatibility with neutral pH formulations further reduces the risk of low-pH-induced irritation, making it suitable for sensitive skin.

Safety and Tolerability

MAP is well-tolerated and considered safe for use in leave-on cosmetic products. It demonstrated no dermal irritation in animal models at standard application doses, no sensitization or allergic response in guinea pig maximization tests, no genotoxicity in bacterial and mammalian cell studies and no systemic toxicity in acute dermal exposure studies [3].

Conclusion

Magnesium Ascorbyl Phosphate is a stable and water-soluble vitamin C derivative that offers clear formulation and skin tolerability advantages over ascorbic acid. Its neutral pH compatibility and low irritation potential make it especially attractive for use in sensitive skin formulations, while maintaining the antioxidant benefits of vitamin C.

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References

1. Kandil, S. M., Soliman, I. I., Diab, H. M., Bedair, N. I., Mahrous, M. H., & Abdou, E. M. (2022). Magnesium ascorbyl phosphate vesicular carriers for topical delivery; preparation, in-vitro and ex-vivo evaluation, factorial optimization and clinical assessment in melasma patients. Drug Delivery, 29(1), 534–547.
   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9040897/

2. Ravetti, S., Clemente, C., Brignone, S., Hergert, L., Allemandi, D., & Palma, S. (2019). Ascorbic acid in skin health. Cosmetics, 6(4), 58.
   https://www.mdpi.com/2079-9284/6/4/58

3. Cosmetic Ingredient Review Expert Panel. (2024). Safety assessment of ascorbic acid and ascorbates as used in cosmetics. Cosmetic Ingredient Review, Re-Review for Panel Consideration, September 6, 2024.
   https://www.cir-safety.org/sites/default/files/Ascorbic%20Acid.pdf