Oxyquinoline Sulfate
molecular structure · PubChem
AKA: 8-Hydroxyquinoline sulfate, Hydroxyquinoline sulfate, Oxine sulfate, Oxyquinoline sulphate, 8-Quinolinol sulfate (2:1) (salt), CRIPTONOL
Synthetic
Preservative
Chelating Agent
Not Clean
bis(8-Hydroxyquinolinium) sulphate
Solubility greater than or equal to 100 mg/mL at 66 °F (NTP, 1992)
Formula
C18H16N2O6S
Mol. Weight
388.40
CAS #
134-31-6
Form
Powder
State
8-hydroxyquinoline sulfate is a pale yellow to yellow crystalline powder with a slight saffron odor. Burning taste. (NTP, 1992)
Functions
Antimicrobial
Keeps your product from growing bacteria, mold, or yeast. Without these, that jar of cream becomes a petri dish in about a week.
Chelating
Grabs onto metal ions in water that would destabilize the formula. Keeps your product from going bad or changing color.
Fights Bacteria
Traditional Use
The sulfate salt form of oxyquinoline was developed as a more stable antimicrobial preservative for cosmetics. It has been used since the early-to-mid 20th century as a preservative and anti-fungal agent.
EWG
6
CIR
Insufficient data
Pregnancy
No
CIR Safety Findings
all-shades-safe
Concentration Guide
0.3%
0%0%
Reg. Limit
EU regulatory limit: 0.3%. (a) 0.3% (as base) (b) 0.03% (as base) Source: EU Cosmetics Regulation (EC) 1223/2009, Annex III (Restricted Substances), Entry 51.
Regulatory Agencies
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
No
The paper trail
🔬Peer-reviewednone on file
⚖️Regulatory1 listing →
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR