Strontium hydroxide
Safety score · 0–100
Caution
Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.
About
An alkaline compound permitted in EU Annex III at up to 3.5% (as strontium) for specific cosmetic uses such as depilatories, but requiring careful formulation due to its caustic nature.
Strontium hydroxide is listed in EU Annex III with a specific concentration limit of 3.5% (expressed as strontium). It is used primarily in hair-removal (depilatory) products where its alkaline properties enable the dissolution of keratin. The relatively moderate safety score reflects the controlled but genuine hazard of this caustic substance when used within the permitted concentration range. Outside of these specific uses, it is not considered appropriate for general skin care applications.
Skin benefits
- Keratin dissolution (depilatory action)
- pH adjustment in controlled formulations
Known concerns
- Caustic/alkaline hazard at higher concentrations
- Restricted to 3.5% (as strontium) in EU Annex III
- Skin irritation potential
References
EU CosIng database
European Commission cosmetic ingredient registry — regulatory status, restrictions, authorised functions.
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This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve — always read the physical product label and consult a healthcare professional for personal concerns.