PROPYLENE OXIDE

US conditions: California CSCP: reported in 7 cosmetic product(s)

📊 Comedogenicity

📚 Research & Evidence

🔬 The Science

The available research on propylene oxide does not include consumer skincare studies. Here’s what the literature actually shows:

#1: Antimicrobial potential under specific conditions — A 1983 study in *J Hyg (Lond)* tested propylene oxide (at 3.4% concentration in a specific formulation) against bacterial spores and found it had sporicidal activity (meaning it could kill spores), but only when temperature was controlled and elevated during storage. The same study noted that chlorhexidine, a common antimicrobial, showed no such activity under the same conditions. However, this research was conducted on pre-injection medical swabs, not skin products. #2: Use in drug-delivery polymers — A 2000 study in *J Control Release* investigated propylene oxide as part of a larger copolymer (PEO-PPO-PEO) designed to deliver pharmaceutical drugs through skin.

The copolymer itself, not propylene oxide alone, was the active component. A 2016 study in *Colloids Surf B Biointerfaces* examined modified copolymers of ethylene oxide and propylene oxide for potential spinal cord drug delivery in medical contexts—again, not for cosmetic skincare. #3: Occupational safety data exists but has limitations — A 1981 study in *J Occup Med* examined workers in alkylene oxide manufacturing plants. It found increased chromosome aberrations in employees with long-term exposure (over 20 years), though the study noted workers were exposed to multiple substances, making it impossible to attribute effects solely to propylene oxide. This data concerns industrial workplace exposure, not consumer product safety.

In summary: the research base for propylene oxide as a skincare ingredient is essentially absent. Available studies focus on sterilization, pharmaceutical delivery systems, and occupational safety—not topical beauty applications.

💧 Skin Type Compatibility

⚠️ Don’t Combine With

🧴 Products Containing PROPYLENE OXIDE

📄 Related Research

Matched by search — not necessarily verified support for every statement above.

• Unknown authors (1976). Propylene oxide. IARC Monogr Eval Carcinog Risk Chem Man.
• Wright RC (1983). The sterilizing capacity of propylene oxide and chlorhexidine diacetate solutions upon pre-injection swabs saturated with propan-2-ol. J Hyg (Lond).
• Liaw J et al. (2000). Evaluation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) gels as a release vehicle for percutaneous fentanyl. J Control Release.
• Kamalov MI et al. (2016). Non-invasive topical drug delivery to spinal cord with carboxyl-modified trifunctional copolymer of ethylene oxide and propylene oxide. Colloids Surf B Biointerfaces.
• Thiess AM et al. (1981). Mutagenicity study of workers exposed to alkylene oxides (ethylene oxide/propylene oxide) and derivatives. J Occup Med.