murphyPotassium Sulfite
AKA: 10117-38-1, Dipotassium sulfite, Potassium sulphite, Sulfurous acid, Dipotassium salt, Potassium sulfite (K2SO3), Potassium salt, HSDB 5052
Synthetic
Antioxidant
Preservative
Not Clean
OriginPotassium sulfite is a salt compound synthesized from the chemical family of inorganic sulfites containing potassium. It is produced by reacting sulfur dioxide with potassium hydroxide or potassium carbonate in aqueous solution.
Potassium sulphite
Solubility White crystals or crystalline powder; sol in about 3.5 parts water; decomposed by diluted acids with evolution of sulfur dioxide; pH about 8 /dihydrate/
Formula
K2O3S
Mol. Weight
158.26
CAS #
10117-38-1, 23873-77-0
Form
Liquid
State
Liquid
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-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
4
CIR
Reviewed by CIR
Pregnancy
Caution
Concentration Guide
0%50%100%
Reg. limit 0.2%
CIR's newest survey reports no concentration of use.
CIR · 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