murphySodium Metaphosphate
AKA: Kurrol's salt, Sporix, Maddrell's salt, Sodium Kurrol's salt, Insoluble metaphosphate, Sodium metaphosphate (NaPO3), SODIUM METAPHOSPHATE (NA(PO3))
Synthetic
Chelating Agent
Clean
OriginSodium metaphosphate is synthesized from phosphoric acid and sodium compounds through high-temperature condensation reactions. The resulting glassy sodium polyphosphate is then processed and refined to create the final ingredient.
The CIR Expert Panel concluded that the following 31 ingredients are safe in the present practices of use and concentration in cosmetics as described in this safety assessment, when formulated to be non-irritating...Sodium Metaphosphate...
Solubility White powder. Practically insol in water and in aq solns of pyrophosphates and hexametaphosphates. Sol in mineral acids. Does not form complexes with Fe(II), Fe(III), U(IV) salts. /Maddrell's salt (polymeric sodium metaphosphate)/
Formula
NaO3P
Mol. Weight
101.96
CAS #
10361-03-2, 50813-16-6
Form
Powder
State
White solid, practically insoluble in water; [Merck Index]
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
Functions
Buffering
Chelating
Grabs onto metal ions in water that would destabilize the formula. Keeps your product from going bad or changing color.
Oral Care
Stabilizes pH
Removes Metal Ions
Antioxidant Protection
Reduces Inflammation
Locks In Moisture
Supports dental health, Maintains optimal pH, Binds metal ions
The paper trail
🔬Peer-reviewednone on file
⚖️Regulatory1 listing →
🛡️Safety-assessed4 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
1
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not an Eye Irritant
1 study / 1 not irritating (CIR 710)
Skin Irritant in Testing
2 studies / 2 irritating / reactions mild (CIR 333 and 710)
Concentration Guide
Leave-on0.01–9.6%
Rinse-off0.01–0.2%
0%50%100%
CIR reported use · 2015 survey
Regulatory Agencies
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR