murphySodium Metabisulfite
AKA: 7681-57-4, Sodium pyrosulfite, Sodium disulfite, Disodium pyrosulfite, Natrii disulfis, Campden Tablets, Disodium metabisulfite, Natrium pyrosulfit, Natriummetabisulfit
Synthetic
Antioxidant
Preservative
Not Clean
OriginProduced from sulfur dioxide and sodium carbonate through chemical synthesis. Created by combining these precursor chemicals under controlled industrial conditions.
Sodium metabisulfite appears as a white crystalline or powder solid with a slight sulfur odor. Toxic by inhalation. Strongly irritates skin and tissue. Noncombustible, but may decompose to emit toxic oxide fumes of sulfur and sodium when heated to high temperature. A corrosive acid when mixed with water. Used as a food preservative and as a laboratory reagent.
Solubility 54 % (NIOSH, 2024)
Formula
Na2O5S2
Mol. Weight
190.11
CAS #
7681-57-4, 7757-74-6
Form
Powder
State
Sodium metabisulfite appears as a white crystalline or powder solid with a slight sulfur odor. Toxic by inhalation. Strongly irritates skin and tissue. Noncombustible, but may decompose to emit toxic
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.
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
6
CIR
Safe as used
Pregnancy
Caution
CIR Safety Findings
Phototoxic in Testing
Lab (in vitro) test with a phototoxic or photosensitizing result in the CIR safety assessment (CIR 303)
Mixed Skin Irritation Results
4 studies / 1 irritating / 3 not irritating (CIR 303)
Mixed Eye Irritation Results
2 studies / 1 irritating / 1 not irritating / reactions mild (CIR 303)
Concentration Guide
Leave-on0.0001–0.25%
Rinse-off0.000005–0.6%
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