Cosmetics · Quasi-drug actives
Magnesium Ascorbyl Phosphate
アスコルビン酸リン酸Mg (Asukorubin-san rinsan magunesiumu)
Also known as: MAP
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| Category | Cosmetics |
|---|---|
| INCI name | Magnesium Ascorbyl Phosphate↗ |
| Japanese labeling name | アスコルビン酸リン酸Mg |
| Common Japanese notations | アスコルビン酸リン酸Mg, リン酸アスコルビルマグネシウム |
| CAS number | 113170-55-1↗ |
| Origin | Synthetic (vitamin C derivative) |
| Typical functions | Quasi-drug whitening active, Antioxidant |
| Regulatory status in Japan | Approved as a quasi-drug (医薬部外品) whitening active by 厚生労働省 (Ministry of Health, Labour and Welfare). |
Magnesium ascorbyl phosphate (MAP) is one of the established stable vitamin C derivatives used in Japanese cosmetics and quasi-drug whitening products. The phosphate conjugation stabilizes the ascorbate moiety against oxidation, with in vivo enzymatic conversion back to active vitamin C.
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Classification
Tags below link to other ingredients sharing the same attribute, so you can pivot from one ingredient to its peers.
Product applications
Regulatory tags
Origin
Common OEM product categories
Finished-product categories where Japanese OEM manufacturers commonly formulate with this ingredient.
- Medicated whitening products
- Brightening serums and lotions
- Anti-aging skincare
Ingredient profile
MAP is the magnesium salt of L-ascorbic acid 2-phosphate. The phosphate group at the C2 position protects ascorbate from oxidation; in vivo phosphatase enzymes can release the free ascorbate.
OEM applications
In Japanese cosmetics, MAP appears in medicated whitening products and brightening-positioned skincare across many brands.
Regulatory classification in Japan
Approved as a quasi-drug whitening active by 厚生労働省 (Ministry of Health, Labour and Welfare).
Regulatory classification in other markets
| EU | Listed in CosIng. Permitted for cosmetic use. |
|---|---|
| USA | INCI recognized. |
| China | Permitted per IECIC listings. |
| Korea | Permitted under KFDA / MFDS. |
Market reference formulations
Example finished products will be added after each product's current full ingredient list has been verified.
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Typical OEM use levels
Formulation ranges per finished-product application. Verify against the cited source before production.
| Application | Typical range | Regulatory limit | Notes |
|---|---|---|---|
| Quasi-drug whitening serum / lotion (Japan) | 3% | 3% per 厚生労働省 quasi-drug notification (representative) | 厚生労働省 医薬部外品有効成分通知 |
| Cosmetic brightening serum (overseas) | 1–3% | — | — |
Stability & compatibility
- pH range
- pH 6.5–8.0
- Temperature
- More heat-stable than L-ascorbic acid; tolerates standard processing
- Incompatibilities
- Low pH (<6) — drops solubility
- High concentrations of metal ions without chelation
Stable salt-form derivative of vitamin C. Preferred over L-ascorbic acid where formulation pH is neutral.
Storage requirements
How the receiving OEM facility needs to handle inbound raw material.
- Temperature
- ≤25°C
- Conditions
- Dry, sealed; protect from light
- Shelf life
- 24 months sealed
Showa Denko / supplier SDS
Supply concentration
Where this ingredient comes from — useful for single-source-risk planning.
- Primary regions
- Synthetic; Showa Denko historically a primary Japanese supplier; widely available globally
- Import dependence
- Mixed domestic / import supply
Alternative ingredients
Related ingredients commonly evaluated as substitutes.
Quick answers
- What is Magnesium Ascorbyl Phosphate?
- Magnesium ascorbyl phosphate (MAP) is one of the established stable vitamin C derivatives used in Japanese cosmetics and quasi-drug whitening products. The phosphate conjugation stabilizes the ascorbate moiety against oxidation, with in vivo enzymatic conversion back to active vitamin C.
- What is the regulatory status of Magnesium Ascorbyl Phosphate in Japan?
- Approved as a quasi-drug (医薬部外品) whitening active by 厚生労働省 (Ministry of Health, Labour and Welfare).
- What products typically use Magnesium Ascorbyl Phosphate?
- Medicated whitening products / Brightening serums and lotions / Anti-aging skincare
- Where does Magnesium Ascorbyl Phosphate come from?
- Synthetic (vitamin C derivative)
- What is the INCI / JSCI labeling name for Magnesium Ascorbyl Phosphate?
- INCI: Magnesium Ascorbyl Phosphate / JSCI: アスコルビン酸リン酸Mg
Explore related ingredients
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Sharing similar functions
Ingredients that overlap on functional benefit tags.
From the same origin
Other ingredients that share an origin classification.
Manufacturers mentioning this ingredient
Japanese OEM factories whose published profile references this ingredient. Auto-detected from manufacturer descriptions; verify capabilities directly.
Regulatory guidance
Take the next step
FAQ for OEM buyers
Q. Is magnesium ascorbyl phosphate (MAP) approved as a quasi-drug active in Japan?
Yes — MAP is on the 厚生労働省 (Ministry of Health, Labour and Welfare) quasi-drug whitening active list (typically denoted リン酸L-アスコルビルマグネシウム); finished products with whitening claims must be filed as quasi-drugs.
Sources · Last reviewed: 2026-04-26
- 厚生労働省 (Ministry of Health, Labour and Welfare) — quasi-drug whitening actives
Q. How does MAP compare with sodium ascorbyl phosphate (SAP)?
MAP and SAP are both phosphate-stabilized vitamin C derivatives with similar conversion to ascorbic acid in skin; MAP is more often used in Japanese whitening quasi-drugs, while SAP is more common in EU/US brightening cosmetics. Solubility and pH ranges differ slightly.
Sources · Last reviewed: 2026-04-26
- Industry knowledge — vitamin C derivative selection
Industry-knowledge claim — not yet pinned to a single primary source
Q. What is the typical use level and stability range?
Quasi-drug formulations typically use MAP at around 3%; it is most stable at pH 7–8.5, which is higher than most other vitamin C forms and often determines the final formulation pH.
Sources · Last reviewed: 2026-04-26
- Industry knowledge — MAP formulation practice
Industry-knowledge claim — not yet pinned to a single primary source
Q. Are there formulation incompatibilities to watch for?
MAP can precipitate with divalent cations (calcium, zinc) at certain levels; chelating agents and careful order of addition are recommended to prevent haze and instability.
Sources · Last reviewed: 2026-04-26
- Industry knowledge — MAP incompatibilities
Industry-knowledge claim — not yet pinned to a single primary source
Use cases
Medicated whitening lotion
- Positioning
- Mainstream Japanese daily-use whitening regimen
- Typical usage level
- ~3% (Japan quasi-drug)
- Formulation notes
- pH 7–8 water-phase; chelators included; pair with niacinamide.
Sources
- Industry knowledge — Japanese medicated whitening practice
Industry-knowledge claim — not yet pinned to a single primary source
Brightening cream / emulsion
- Positioning
- Brightening + moisturization combined positioning
- Formulation notes
- Use in water phase; avoid divalent salts in same phase.
Sources
- Industry knowledge — brightening cream formulation
Industry-knowledge claim — not yet pinned to a single primary source
Brightening sheet mask
- Positioning
- Daily brightening single-use mask
- Formulation notes
- Compatible with HA and niacinamide; stable in mask serum at slightly alkaline pH.
Sources
- Industry knowledge — sheet mask category
Industry-knowledge claim — not yet pinned to a single primary source
Anti-acne brightening serum
- Positioning
- Vitamin C derivative for post-acne mark care
- Formulation notes
- Combined with niacinamide and salicylic acid (within Japanese quasi-drug acne approvals).
Sources
- Industry knowledge — post-acne brightening segment
Industry-knowledge claim — not yet pinned to a single primary source
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Official regulatory databases
External links to public Japanese / international regulatory authorities. We are not affiliated.
References
- Japan 医薬品医療機器総合機構 PMDA (Pharmaceuticals and Medical Devices Agency) — quasi-drug active ingredient approval registry
- EU CosIng entry: Magnesium Ascorbyl Phosphate
Last updated: 2026-04-22. Ingredient entries are reviewed at least annually against current regulatory listings.