Quick answer

Water-soluble yet oil-loving stabilized form of vitamin C; Delivers many of the same benefits as vitamin C; Promotes hydration deeper in skin, but not as potent an antioxidant as pure vitamin C; Isn’t beholden to a low pH for efficacy and is generally well tolerated; Soothing properties may play a role in reducing blemishes Key benefits: Anti-Aging, Hydration.

Magnesium Ascorbyl Phosphate

Vitamin C

Updated

Ascorbic acid, monoester with phosphoric acid, magnesium salt (2:3)

Purpose

Stable, hydrating form of vitamin C known to brighten dullness and improve skin’s firm look and feel.

Rating

BEST

Category

Antioxidant, Humectant

INCI Purpose

ANTIOXIDANT, SKIN CONDITIONING

Benefits

Anti-Aging — Boosts collagen and cell turnover to reduce fine lines and wrinkles
Hydration — Attracts and locks in moisture to keep skin plump and dewy

Alternative Names

At a Glance

Water-soluble yet oil-loving stabilized form of vitamin C

Delivers many of the same benefits as vitamin C

Promotes hydration deeper in skin, but not as potent an antioxidant as pure vitamin C

Isn’t beholden to a low pH for efficacy and is generally well tolerated

Soothing properties may play a role in reducing blemishes

Article

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.

Like most forms of vitamin C, magnesium ascorbyl phosphate has been shown to improve the look of an uneven skin tone when used in concentrations between 2-5%. Concentrations between 5-10% are known to have more pronounced benefits for discolorations, including post-breakout marks, as well as improving skin’s firm look and feel. Amounts below 2% all the way down to 0.1% still deliver antioxidant benefits.

Magnesium ascorbyl phosphate does not require the same low pH ascorbic acid does in order to be effective. It works best at pH levels between 5-6. Going above pH 6 can cause this ingredient to discolor.

This form of vitamin C may play a special role in reducing the likelihood of blemishes since its soothing action helps quell an of oil-based saccharide that can irritate skin. However, research on this matter was not comparative, meaning we don’t know how a range of other forms of vitamin C would’ve fared.

It is considered safe as used in cosmetics.

References

International Journal of Biological Macromolecules, January 2021, pages 333-341 The Journal of Clinical and Aesthetic Dermatology, July 2017, pages 14-17; and July 2010, pages 20-31 Annals of Dermatology, February 2016, pages 129-132; and August 2015, pages 376-382 International Journal of Dermatology, January 2014, pages 93-99 Indian Dermatology Online Journal, April-June 2013, pages 143-146 Skin Research and Technology, August 2008, pages 376-380 International Journal of Toxicology, Supplement 24, 2005, pages 51-111