Vitamin C (Magnesium Ascorbyl Phosphate, Sodium Ascorbyl Phosphate, & Ascorbic Acid)

vitamin c (magnesium ascorbyl phosphate or ascorbic acid) in skincare

Vitamin C comes in many forms, and our favorites are magnesium ascorbyl phosphate (a.k.a. MAP) and sodium ascorbyl phosphate (a.k.a. SAP), because they convert to ascorbic acid, the most powerful form of vitamin C for the skin. This active ingredient has a myriad of research proving that it is safe and effective, providing many anti-aging benefits including antioxidant protection, calming and soothing properties, and improving the look of uneven skintone. In short, it's an anti-aging superpower!

We are very proud to use MAP and SAP, two forms of vitamin C whose effectiveness and safety is backed up by the latest research. Many skincare companies use ascorbic acid, a form of vitamin C that carries some risks (see below).

Quick Guide toVitamin C

Function Active ingredient
Skin types


Mature and aging skin

Acne-prone skin

Inflamed and irritated skin


Skin exposed to UV radiation and/or environmental toxins

Products Custom Hyaluronic Acid Serum
Best time to use Day or night



Vitamin C must be used at relatively high concentrations in order to be effective. MAP and SAP are forms of vitamin C that are well suited for those with sensitive skin, because their effective concentration is lower than the most commonly used form of vitamin C (ascorbic acid), reducing risk of irritation.


Activist Skincare has chosen to use the MAP and SAP versions of vitamin C rather the more commonly found form, ascorbic acid. Although ascorbic acid is among the safest and most effective anti-aging skincare ingredients available, it is not stable. When exposed to air, heat, and light, ascorbic acid oxidizes, eliminating its effectiveness on the skin and increasing the formation of free radicals, which damage the skin. 

If a lotion or serum changes to an orange, tan or brown color, this indicates that oxidation has reached a dangerous level, and the product should be discarded immediately to avoid free radical damage to the skin.

MAP, or magnesium ascorbyl phosphate, and SAP, or sodium ascorbyl phosphate, are several times more stable than ascorbic acid, so it's safe to use these forms of vitamin C in water-based formulas and in situations where it will be exposed to light and air, like your bathroom. Your skin automatically converts MAP and SAP to ascorbic acid, so you get all the benefits with much less risk.