PENTASODIUM TRIPHOSPHATE

Also known as: Pentasodium Triphosphate

INCI: PENTASODIUM TRIPHOSPHATE | Function: Buffering Agent, Chelating Agent | Type: Synthetic phosphate salt (chelating/buffering)

What Is PENTASODIUM TRIPHOSPHATE?

Pentasodium Triphosphate (STPP) is a sodium salt of triphosphoric acid. It is a common water softener and chelating agent in rinse-off personal care products. It sequesters hard water minerals, preventing soap scum formation and improving cleansing efficacy.

Key Skin Benefits

+ Excellent water softening for hard water areas
+ Prevents soap scum — cleaner rinse
+ Chelating — removes metal ion interference
+ Cost-effective and widely available

Pros

+ Very effective in hard water
+ Improves foam and cleansing in soaps
+ Well-known, extensively studied

Cons

− Rinse-off only
− Environmental concern — phosphate pollution/eutrophication
− Alkaline pH — may be irritating at high concentrations

Specifications

Property	Value
Usage Areas	Face, Body
Product Type	Rinse-Off
Source	Synthetic
Natural Level	Synthetic

Safety Ratings

Metric	Rating
Skin Sensitivity	2/5 (low)
Comedogenic Rating	0/5
EWG Score	3/10

Regional Regulatory Limits

Region	Leave-on %	Rinse-off %	Status
EU (CosIng)	No limit	No limit	Allowed
US (CIR/FDA)	No limit	No limit	Allowed
Japan (MHLW)	No limit	No limit	Allowed
ASEAN	No limit	No limit	Allowed
China (NMPA)	No limit	No limit	Allowed

Typical Usage % by Product Type

Product Type	Typical %
Soap / Body wash	0.5 - 2%
Shampoo	0.2 - 1%
Bath salts	1 - 5%

References

CIR — Safety Assessment of phosphates. PMID: 11444224
EU CosIng Database — Listed as buffering/chelating.
SpecialChem — Sodium Tripolyphosphate cosmetic

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