Magnesium ascorbyl phosphate
Magnesium ascorbyl phosphate suppliers and sourcing guide
Magnesium ascorbyl phosphate is the magnesium salt of ascorbic acid phosphorylated at the 2-position. It is made by phosphorylating ascorbic acid, then forming and purifying the magnesium salt, and is sold as a white to off-white, water-soluble powder. It is most stable near neutral pH, so it suits formulas around pH 6 to 7. Suppliers sell it as a hydrate, so the water content and the stated basis of the assay matter when setting use levels.
- Category
- Cosmetic actives
- Also known as
- magnesium L-ascorbyl-2-phosphate · MAP · ascorbyl monophosphate magnesium salt · CAS 113170-55-1
- Facts checked
- November 2026
Forms and grades of magnesium ascorbyl phosphate
Suppliers sell different products under the same name. Specify the one you need.
Cosmetic grade powder
White powder of high purity, the standard form for skin care.
Low-color grades
Grades with tighter color and free ascorbic acid limits for clear or white products.
Pre-blended solutions
Supplier blends of magnesium ascorbyl phosphate in water or glycol; check the active percentage on the COA.
What to check on the COA
Compare each result with your own specification when the lot arrives.
- Assay (HPLC)
- Magnesium ascorbyl phosphate content by HPLC, with the basis (dried or as-is) stated.
- Free ascorbic acid and phosphate
- Free ascorbic acid and free phosphate, which indicate breakdown of the ester.
- Water content
- Loss on drying or Karl Fischer water, since the material is a hydrate.
- Solution pH, clarity and color
- pH, clarity and color of a test solution.
- Heavy metals
- Lead, arsenic and other metals by ICP-MS.
Storage, lots and expiry
Storage and shelf life
Store in a tightly closed container in a cool, dry place, protected from light and humidity, which cause caking and discoloration. Shelf life and retest intervals are set by the supplier.
Lots and expiry dates
Record the assay basis, water content and free ascorbic acid for each lot. Check solution color on receipt and rotate oldest first.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
Health Canada's Natural Health Products Ingredients Database lists magnesium ascorbyl phosphate as an approved ingredient for topical use only, up to 3%, citing CIR.
Source: webprod.hc-sc.gc.ca (opens in a new tab)The same entry lists the proper name magnesium L-ascorbyl-2-phosphate, a CAS number of 114040-31-2, and skin-conditioning agent among its non-medicinal purposes.
Source: webprod.hc-sc.gc.ca (opens in a new tab)
This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
Magnesium ascorbyl phosphate suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking magnesium ascorbyl phosphate suppliers now
Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.
Sell magnesium ascorbyl phosphate? Request a listingFrequently asked questions
What forms of magnesium ascorbyl phosphate can brands buy?
Common forms include cosmetic grade powder, low-color grades and pre-blended solutions. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for magnesium ascorbyl phosphate include?
Expect assay (HPLC), free ascorbic acid and phosphate, water content, solution pH, clarity and color and heavy metals, each with its method, specification and result for that lot.
How should magnesium ascorbyl phosphate be stored?
Store in a tightly closed container in a cool, dry place, protected from light and humidity, which cause caking and discoloration. Shelf life and retest intervals are set by the supplier.
What is the regulatory status of magnesium ascorbyl phosphate?
Health Canada's Natural Health Products Ingredients Database lists magnesium ascorbyl phosphate as an approved ingredient for topical use only, up to 3%, citing CIR. The same entry lists the proper name magnesium L-ascorbyl-2-phosphate, a CAS number of 114040-31-2, and skin-conditioning agent among its non-medicinal purposes.
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