murphySodium Sulfite
AKA: 7757-83-7, Disodium sulfite, Sodium sulfite anhydrous, Sodium sulphite, Sulfurous acid, Disodium salt, Natrium sulfurosum, Sulftech, Natriumsulfid, Natriumsulfit
Synthetic
Antioxidant
Preservative
Not Clean
OriginDerived from sulfur dioxide and sodium compounds through chemical synthesis. Produced by reacting sodium carbonate or sodium hydroxide with sulfur dioxide gas.
Sodium Sulfite is a white crystal or powder with reducing property. Sodium sulfite exhibits bleaching, de-sulfurizing, and dechlorinating activities. This agent was used by food industry to help maintain the fresh appearance of food products. It is also a component in many drugs, which helps maintain their potency and stability. FDA has ruled sodium sulfite a new animal drug of low regulatory priority.
Solubility Soluble in 3.2 parts (NTP, 1992)
Formula
Na2O3S
Mol. Weight
126.05
CAS #
7757-83-7
Form
Powder
State
Sodium sulfite is a white odorless powder. Density 2.633 g / cm3. Moderately toxic. Sinks in water and dissolves slowly. Also transported as a heptahydrate Na2SO3.7H2O.
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Caution
Functions
Antioxidant
Fights free radicals — the unstable molecules from UV, pollution, and stress that break down collagen and cause premature aging.
Hair Waving Or Straightening
Preservative
Keeps your product from growing bacteria, mold, or yeast. Without these, that jar of cream becomes a petri dish in about a week.
Reducing
Neutralizes Free Radicals
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
4
CIR
Safe as used
Pregnancy
Caution
CIR Safety Findings
Not a Skin Irritant
2 studies / 2 not irritating (CIR 303)
Not a Sensitizer
3 studies / 3 not sensitizing / plus 2 case reports (CIR 303 CIR 802)
Phototoxic in Testing
Lab (in vitro) test with a phototoxic or photosensitizing result in the CIR safety assessment (CIR 303)
Concentration Guide
Leave-on0.0000051–0.12%
Rinse-off0.000001–3%
0%50%100%
Reg. limit 0.2%
CIR reported use · 2019 survey
EU regulatory limit: 0.2%. SO2) Source: EU Cosmetics Regulation (EC) 1223/2009, Annex V (Preservatives), Entry 9.
Regulatory Agencies
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR