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Formaldehyde-releasing preservative

5-Ethyl-3,7-dioxa-1-azabicyclo[3.3.0] octane

CAS 7747-35-5
35

Safety score · 0–100

Caution

Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.

A bicyclic oxazolidine preservative that slowly releases formaldehyde, a Group 1 human carcinogen and sensitizer. Restricted under EU Annex V and increasingly phased out by major cosmetic brands.

Skin benefits

  • Effective broad-spectrum preservative
  • Used at low concentrations for shelf-life extension

Known concerns

  • Formaldehyde-releasing preservative (releases formaldehyde in solution)
  • Formaldehyde is a known human carcinogen (IARC Group 1)
  • Restricted under EU Annex V with mandatory warnings
  • Common cause of contact allergy in cosmetics
  • Many brands phase out formaldehyde donors due to safety concerns

References

EU

EU CosIng database

European Commission cosmetic ingredient registry: regulatory status, restrictions, authorised functions.

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3-Ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine
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Cis-1-(3-chloroallyl)-3,5,7- triaza-1-azoniaadamantane chloride (cis-CTAC)
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This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve, so always read the physical product label and consult a healthcare professional for personal concerns.