Magnesium Ascorbyl Phosphate

CAS No- 114040-31-2

Magnesium ascorbyl phosphate (MAP, for short) is a water-soluble form of vitamin C made by combining ascorbic acid (pure vitamin C) with a magnesium salt to improve its stability in water-based formulas. It is considered stable in the presence of light and air but is not impervious to diminished efficacy when exposure to both elements is persistent.

Unlike other water-soluble forms of vitamin C, magnesium ascorbyl phosphate is also lipophilic, or oil-loving, which improves penetration into skin (although how well this form converts to ascorbic acid within skin is up for debate). Because of its oil-loving nature and its ability to promote hydration deeper in skin when compared to ascorbic acid (which instead showed greater antioxidant ability), MAP is considered one of the most hydrating forms of vitamin C.