Science
Mechanism of Action
This compound acts as an antimicrobial agent by gradually liberating formaldehyde, which disrupts the cellular integrity of bacteria, fungi, and other microorganisms. As a quaternary ammonium compound (QAC), its amphiphilic structure allows it to intercalate into microbial cell membranes, leading to membrane instability and porosity, ultimately preventing proliferation.
Research
Clinical Evidence
High confidence0.2%
Key findings
- 01 Clinical evaluations confirm its efficacy as a preservative in diverse cosmetic formulations such as lotions, shampoos, and eye make-up, with concentrations between 0.1% and 1.0% demonstrated for preservative function.
- 02 The Cosmetic Ingredient Review (CIR) Expert Panel deemed concentrations up to 0.2% safe, reporting no sensitizing effects in most animal and human studies at this level.
Transparency
Dusting Analysis
Despite its established efficacy, Quaternium-15's designation as a formaldehyde-releaser makes its inclusion highly contentious. While some regulations permit up to 0.2%, its use is banned in the European Union and will be in California from 2025, rendering any detectable concentration a significant red flag for precision skincare formulations due to associated health risks.
The Formula
Formulation
Stability
Antimicrobial activity is contingent on the slow release of formaldehyde, which occurs over a broad pH range. It exhibits moisture sensitivity, and acid hydrolysis at low pH values can significantly accelerate formaldehyde liberation. It is soluble in distilled deionized water and buffered solutions at pH 5 and pH 9.
Conflicts
- strong oxidizing agents
Safety
Safety Profile
The CIR Expert Panel considers Quaternium-15 safe in cosmetics at concentrations not exceeding 0.2%. However, regulatory bodies globally have differing stances: the European Union reportedly banned it in 2017, and California Assembly Bill No. 496 prohibits its use in cosmetics from January 1, 2025, both due to formaldehyde-releasing properties. The FDA monitors its use but has no specific cosmetic limits, regulating it as an indirect food additive.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Due to its mechanism involving formaldehyde release and subsequent regulatory bans in key markets like the EU and California, Quaternium-15 is an ingredient to be avoided in precision skincare formulations.
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