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Magnesium ascorbyl phosphate serum OEM/ODM manufacturing
Magnesium Ascorbyl Phosphate (MAP) Serum · OEM/ODM
Magnesium ascorbyl phosphate (MAP) is the magnesium salt of ascorbyl-2-phosphate — vitamin C with a phosphate group attached at carbon 2. The phosphate group at this position protects the molecule from break-up of the enediol system, the weak point that makes ascorbic acid degrade quickly in water; in standard solutions and topical formulations MAP is more stable than ascorbic acid (Austria 1997), and at neutral pH ascorbic acid is less stable than a MAP solution (Geesin 1993). Being stable in the bottle does not mean being effective on the skin, though: on pig skin, MAP did not raise L-ascorbic acid levels in the skin (Pinnell 2001); the collagen and pigment data come mainly from cultured cells; in people, a moisturizer containing 3% MAP reduced the area of brown spots versus the vehicle side in a split-face study of 120 women, but the spots returned after stopping, and a placebo-controlled trial in 20 people was negative. Butter-C therefore builds a MAP serum around claims of antioxidant protection for the formula and skin that looks brighter and more even-toned once tested on the finished product — no whitening, melasma or sun protection claims. MAP goes into the water phase; pH and addition temperature follow the supplier's TDS and are confirmed by stability testing with assays; a chelator limits metal ions, as the CIR advises. The material is not in Butter-C's current stock list, so it is sourced per order with a mandatory COA. Butter-C offers turnkey OEM/ODM manufacturing, from formula development and testing to a labeled finished product and notification dossier.
Formula base
A water-loving vitamin C derivative in a water – glycol serum base
MAP goes straight into the serum's water phase. What must be settled first is the correct salt form, a concentration that can be justified in the safety file, the chelator and a pH range proven by stability testing.
Magnesium Ascorbyl Phosphate — the right substance, the right name
According to PubChem (CID 71587428): C12H12Mg3O18P2, molecular weight 579.08, CAS 113170-55-1 — two ascorbyl phosphate groups with three magnesium ions. The literature also calls it magnesium L-ascorbyl-2-phosphate or VC-PMG. Not to be confused with Sodium Ascorbyl Phosphate (the sodium salt), Ascorbyl Glucoside, 3-O-Ethyl Ascorbic Acid or Ascorbic Acid — each has its own INCI and its own data. Some skin-permeation studies distinguish two different magnesium salt forms, so Butter-C checks the CAS and content on the COA when the material arrives.
Concentration: the CIR survey range and the studies
The CIR Expert Panel report (Elmore 2005) records MAP as functioning as an antioxidant in cosmetics, reported in use at 0.001–3%. Human studies used 3% (a moisturizer, split-face), 5% (combined with nicotinamide and hyaluronic acid) and 10% (a cream). The 2026 re-review concluded that the six ingredients of the group, including MAP, are safe “in the present practices of use and concentration as described in the report” (Ferguson 2026); the summary gives no new concentration range, so levels above 3% need tolerance data for the product itself.
Regulatory status
Magnesium ascorbyl phosphate is not listed in ASEAN Annexes II, III or VI (06/2026 version; searched by name and CAS), so it has no specific concentration limit; the manufacturer demonstrates the safety of the chosen level in the Product Information File (PIF).
Humectant base, chelator and preservation
Glycerin, Butylene Glycol, Sodium Hyaluronate and Panthenol form a light moist base; Hydroxyethylcellulose or Xanthan Gum adds slight body — MAP is a salt, so electrolyte-sensitive thickeners must be viscosity-tested on the sample (formulation experience); Disodium EDTA chelates metal ions; Citric Acid and Sodium Citrate set the pH per the TDS; Phenoxyethanol (up to 1.0% — ASEAN Annex VI, Ref 29) with Ethylhexylglycerin.
Key technical points
“More stable than ascorbic acid” still has to be proven in the actual formula
The general vitamin C serum base is covered on the general page; the four points below are about MAP itself and how to read its data.
Stability: what has been measured
In standard solutions and topical formulations, MAP was more stable than ascorbic acid; the authors explain that the phosphate group at position 2 protects the molecule from break-up of the enediol system (Austria 1997). At 10 mM in phosphate buffer, ascorbic acid and both ascorbyl-2-phosphate salts were relatively stable by their decay rates, but ascorbic acid was unstable at neutral pH compared with solutions of the sodium or magnesium salt (Geesin 1993). More stable does not mean color-stable: color, pH and active content still have to be monitored.
pH and temperature per the TDS, confirmed by stability testing
We have not found a checked source giving an optimal pH range for MAP in cosmetics. The finished-product pH and addition temperature follow the supplier's technical data sheet (TDS) and are then confirmed by a stability study with MAP assays, color and pH-drift monitoring.
Metal ions, chelators and packaging
The CIR Expert Panel notes that certain metal ions may combine with this group of ingredients to give pro-oxidant activity, so formulators should ensure they actually act as antioxidants (Elmore 2005). Butter-C uses a chelator and controls water and raw-material quality; packaging is airtight, light-blocking and has little air headspace — standard practice for antioxidants.
HPLC assay of MAP
An HPLC method exists for determining vitamin C and its derivatives (ascorbyl glucoside, magnesium ascorbyl phosphate, ethyl ascorbic acid) together in cosmetics, with recoveries of 95.6–101.0% (Chen 2015). Butter-C assays at the start and after each stability point; if a percentage is printed on the label, it must match the result to the end of the shelf life.
Three formulation directions
One active, three ways to combine it
Single-active water-based MAP serum
MAP in a humectant water – glycol base (Glycerin, Butylene Glycol, Sodium Hyaluronate, Panthenol), Hydroxyethylcellulose for slight body, Disodium EDTA, a citrate buffer and preservatives. A short ingredient list with the story focused on one vitamin C derivative.
MAP – niacinamide serum
Add niacinamide at 2–5%, the range with human data on even skin tone according to the niacinamide article. A combination of 10% nicotinamide, 5% MAP and 5% hyaluronic acid has been tested for 60 days and was reported safe and well tolerated (Barbosa 2024 — melasma setting, compared with hydroquinone; tolerability data, not a basis for claims). The stability of each active must still be tested in the actual formula; this adds one more assay.
Milky MAP serum for dry skin
MAP in the water phase of a thin oil-in-water emulsion with Squalane, Cetearyl Olivate and Glycerin — a softer feel than the water version. It needs a preservative system that passes ISO 11930 challenge testing, plus monitoring of emulsion stability and viscosity in the presence of electrolytes.
How it differs from existing pages
The vitamin C serum page is the general page for choosing between ascorbic acid and its derivatives; the ethyl ascorbic acid serum uses an ether derivative whose main safety point is contact allergy; the oil-soluble vitamin C oil uses tetrahexyldecyl ascorbate in an oil base. This page is for a serum named after MAP — a water-soluble phosphate salt — built around the stability, metal ions and level of evidence of this ingredient.
Parameters we monitor
What the R&D lab measures on every sample
These are the parameters Butter-C tracks during formula development and scale-up. Specific limits are agreed with you on the approved sample and then written into the product's in-house specification.
- Raw material COA
- INCI Magnesium Ascorbyl Phosphate, CAS 113170-55-1, content, salt form, appearance, manufacturing date; niacinamide (if used): free nicotinic acid.
- Active content
- MAP assayed by HPLC at the start and after each stability point; the figure on the label must match the result to the end of the shelf life.
- Appearance & color index
- Color, odor and clarity; the color index is measured regularly to catch discoloration early.
- pH
- Measured directly at 25°C; the pH range follows the TDS and is fixed by stability testing with assays.
- Viscosity
- Measured with a rotational viscometer, recording spindle and speed; viscosity tracked when MAP is added and at each stability point.
- Stability
- Accelerated aging, freeze–thaw cycles and light exposure in the actual pack, checked against real time; remaining content, color and pH tracked — the basis for setting the shelf life.
- Microbiology & preservative challenge
- Tested at a GLP / ISO 17025-accredited laboratory; ISO 11930 preservative efficacy testing on the final formula.
- Skin assessment
- Tolerance testing as the target market requires; to claim “skin looks brighter and more even-toned”, measure it on volunteers using the serum itself (colorimeter, standardized photos).
Claims
Claims matched to the evidence for MAP
Mechanism: in cultured human dermal fibroblasts, MAP was equivalent to ascorbic acid in stimulating collagen synthesis, while the sodium salt needed at least a tenfold higher concentration (Geesin 1993); MAP reduced melanin formation by the enzyme tyrosinase and by cultured melanoma cells (Kameyama 1996) — cell data. In people: Kameyama 1996 — a 10% MAP cream applied to 34 people with chloasma or age spots and 25 people with normal skin gave a significant lightening effect in 19 of 34 and 3 of 25; the abstract describes no control group and gives no application period. Miyamoto 2002 — split-face comparison with the vehicle in 120 Japanese women aged 25–60 with sun-induced brown spots, a lightening moisturizer containing 3% MAP for 6 months: the total spot area fell significantly versus the vehicle side after one month; 6 months after stopping, the spot area had returned to baseline; the result belongs to the whole moisturizer, and the first author's email belongs to a company. Puvabanditsin 2006 — 20 volunteers, compared with placebo, a 10% MAP cream applied together with a 5% vitamin E cream from 3 days before UVA exposure and then for 12 weeks: no effect in preventing or fading the tan. Barbosa 2024 — randomized, double-blind, 50 women with facial melasma, a combination of 10% nicotinamide + 5% MAP + 5% hyaluronic acid versus 4% hydroquinone for 60 days: both groups improved with no significant difference on days 14 and 60; mMASI fell by 32% versus 43%; colorimetric luminosity decreased more in the hydroquinone group; no serious side effects — a medical setting, and the result belongs to the whole combination. We have not found any controlled trial of MAP on its own on wrinkles in people. Level of evidence: limited.
Antioxidant protection for the formula (cosmetic level)
Basis: the antioxidant function in cosmetics recorded by the CIR (Elmore 2005); figures only when measured on the finished product. Instead of: sun protection, replaces sunscreen, protects skin from UV light.
Helps skin look brighter and more even-toned (to be tested on the finished product)
Basis: the limited data above plus measurements on the serum itself (colorimeter, standardized photos); always paired with a sunscreen recommendation. Instead of: whitening, instant tone-up, fades melasma, fades dark marks, erases brown spots, replaces hydroquinone.
Contains magnesium ascorbyl phosphate, a vitamin C derivative
The INCI is stated correctly; the percentage only when it can be assayed to the end of the shelf life. How much is converted to vitamin C in living human skin has not been fully measured. Instead of: “pure vitamin C”, “equivalent to vitamin C”, “converts to vitamin C in the skin”.
No age-related claims
The collagen data come from cultured cells; there is no trial of MAP on its own on wrinkles in people. Instead of: age-reversing claims, boosts collagen, rejuvenates, reduces wrinkles.
Use sunscreen during the day; label reminders
In a placebo-controlled trial in 20 people, a 10% MAP cream (applied with a 5% vitamin E cream) did not prevent UVA tanning (Puvabanditsin 2006). The label reminds users to patch-test before applying to the whole face, stop if irritation occurs, close tightly and keep away from light; pregnant and breastfeeding women: data specific to topical MAP are insufficient, so consult a doctor. Instead of: non-irritating, safe for moms-to-be, use instead of sunscreen.
Manufacturing specifications
Capabilities
- Texture
- A clear water – glycol serum, a lightly thickened serum-gel or a thin milky serum; colorless to milky white depending on the formula.
- Packaging format
- Dark or frosted light-blocking glass dropper bottles, or airless pump bottles. Volume agreed when packaging is selected.
- Minimum order quantity
- Agreed per order — depends on the formula direction, pack format and raw-material lot.
- Testing
- Performed at a GLP / ISO 17025-accredited laboratory, including an HPLC assay of the active; a certificate of analysis accompanies every batch.
- Documentation
- Product Information File (PIF) and notification dossier prepared by Butter-C, with the MAP COA and stability data.
- Packaging
- Label design, printing and packing run in parallel with formulation; the label carries patch-test and daytime-sunscreen recommendations.
Suggested product concept
A MAP – niacinamide serum in a 30 ml dark glass bottle
One product concept to help you picture the result; not a ready-made product for sale. The actual formula is built around your brand's positioning and price range.
Magnesium Ascorbyl Phosphate
The featured ingredient; sourced per order with a COA for every lot; a level within the 0.001–3% range recorded by the CIR, fixed after stability and tolerance testing; HPLC assay at the start and along the stability plan.
Niacinamide
2–5% according to the niacinamide article; free nicotinic acid checked on the COA.
Glycerin, Butylene Glycol, Sodium Hyaluronate
A light humectant base, fragrance-free and alcohol-free; Disodium EDTA chelates metal ions — its color-protecting effect is confirmed by stability testing.
30 ml dark glass bottle
Dropper and a paper carton to block light; the label lists the full INCI, recommends a patch test, daytime sunscreen and closing the bottle tightly after use.
Customization options
What you can specify
The same product type can serve very different customers. Tell us your requirements in the areas below and our pharmacists will build the matching formula.
Concentration
Within the range recorded by the CIR (0.001–3%), or higher when the safety file can justify it and the product has its own tolerance data.
Combined actives
Niacinamide, Sodium Hyaluronate, Panthenol; each combination needs its own stability and tolerance testing — there are no checked data for pairs with retinoids, AHA/BHA or peptides.
Texture
A clear water serum, a lightly thickened serum-gel or a thin milky serum — this decides the feel and the thickener system.
Time of use
Morning or evening according to the product directions; a daytime version carries a more prominent sunscreen reminder.
Ingredient preferences
Fragrance-free, alcohol-free — please state these at the outset so we can choose the solvent and preservative systems.
Packaging
Dark glass dropper bottle or light-blocking airless pump — this decides how well the serum is protected from light and air.
Further reading
Related topics
Magnesium ascorbyl phosphate in cosmetics
Stability, human evidence, concentrations, safety and regulations for MAP (in Vietnamese).
Vitamin C in cosmetics
L-ascorbic acid and its derivatives, and why the pure form is hard to formulate (in Vietnamese).
Sodium ascorbyl phosphate in cosmetics
The sodium salt of the same ascorbyl phosphate — its own data, not interchangeable with MAP (in Vietnamese).
Niacinamide in cosmetics
An active often paired with MAP in brightening serums: concentrations and human data (in Vietnamese).
Vitamin C serum OEM/ODM manufacturing
The general page: choosing the vitamin C form, pH, base and packaging.
Ethyl ascorbic acid serum OEM/ODM manufacturing
A different direction: an ether derivative of vitamin C that needs tolerance testing because of allergy reports.
How we work
From idea to finished batch
Eight steps and three milestones signed off by both sides: approved sample, notification number, finished batch. Step-by-step details →
Get started
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