murphySodium Bisulfite
AKA: 7631-90-5, Sodium hydrogen sulfite, Sodium hydrogensulfite, Sodium bisulphite, Monosodium sulfite, Sulfurous acid, Monosodium salt, Sodium sulhydrate, Uantax SBS, Hydrogen sodium sulfite
Synthetic
Antioxidant
Preservative
Not Clean
OriginProduced from sulfur dioxide and sodium carbonate or sodium hydroxide through chemical combination. Synthesized by absorbing sulfur dioxide gas into alkaline sodium solutions to form the bisulfite salt.
Sodium hydrogensulfite is an inorganic sodium salt having hydrogensulfite as the counterion. It has a role as a mutagen, an allergen, a reducing agent, a food antioxidant and a food colour retention agent. It is an inorganic sodium salt and a sulfite salt. It contains a hydrogensulfite.
Solubility 29 % (NIOSH, 2024)
Formula
HNaO3S
Mol. Weight
104.06
CAS #
7631-90-5
Form
Powder
State
Sodium bisulfite appears as white crystals or crystalline powder. Slight sulfurous odor. Specific gravity 1.48. Strong irritant to skin and tissue.
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
5
CIR
Reviewed by CIR
Pregnancy
Caution
CIR Safety Findings
Not a Skin Irritant
1 study / 1 not irritating (CIR 303)
Concentration Guide
Leave-on0.0013–0.1%
Rinse-off0.013%
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