Disodium Phosphate

AKA: 7558-79-4, Sodium phosphate dibasic, Disodium hydrogen phosphate, Disodium hydrogenorthophosphate, Acetest, Dibasic, Dibasic sodium phosphate, Disodium acid phosphate, Disodium hydrogenphosphate
Synthetic
Clean
Disodium hydrogenorthophosphate
Solubility greater than or equal to 100 mg/mL at 68 °F (NTP, 1992)
Formula
HNa2O4P
Mol. Weight
141.96
CAS #
7558-79-4, 7782-85-6
Form
Powder
State
Sodium phosphate, dibasic appears as a colorless to white crystalline solid. Soluble in water. The primary hazard is the threat to the environment. Immediate steps should be taken to limit spread to t
Functions
Anticorrosive
Buffering
Antioxidant
Anti-Inflammatory
Boosts Collagen
Provides scent
Prevents product degradation
Maintains optimal pH
Traditional Use
Discovered as a naturally occurring phosphate compound in the 18th-19th century. First used in cosmetics as a pH buffer and chelating agent in mid-20th century formulations.
EWG
1
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Skin Types
all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper
⚖️Regulatory1 listing
🛡️Safety-assessed2 reviews
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR