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Moumoujus

OCTOXYNOL-8.

Questionable CAS 9002-93-1 / SURFACTANT - CLEANSING, SURFACTANT - EMULSIFYING

OCTOXYNOL-8 is a synthetic surfactant molecule engineered to reduce surface tension between disparate phases, effectively enabling the formation of stable emulsions. Its inherent amphiphilic properties also facilitate its role as a cleansing agent, solubilizing lipid-based impurities for efficient removal from the skin.

Summary

Emulsifying Agent Surfactant Cleansing Agent

Science

Mechanism of Action

As a non-ionic surfactant, OCTOXYNOL-8 functions by positioning itself at oil-water interfaces, significantly lowering interfacial tension. This action allows otherwise immiscible liquids to disperse uniformly, creating stable emulsions. On the skin, this mechanism translates to enhanced cleansing, where it effectively encapsulates sebum, environmental pollutants, and other hydrophobic debris, enabling their easy rinse-off.

Research

Clinical Evidence

Low confidence
Effective range N/A
Optimal

N/A

Transparency

Dusting Analysis

Not commonly dusted

The Formula

Formulation

Solubility
Oil
Optimal pH N/A
0 7 14

Stability

Optimal pH stability for OCTOXYNOL-8 is not extensively characterized; however, data for a related octoxynol derivative suggests a stable range of pH 5.0 to 8.0 in solution. As an oil-soluble surfactant, it is critical for emulsification. Formulators must meticulously control for impurities such as 1,4-dioxane, ethylene oxide, and residual C9 phenols, given that shorter-chain octoxynols, including OCTOXYNOL-8, may exhibit enhanced percutaneous absorption.

Conflicts

  • Strong oxidizing agents
  • Strong reducing agents

Safety

Safety Profile

CIR Status
Safe with restrictions
Max tested
5%%
Sensitization risk Unknown

The Cosmetic Ingredient Review (CIR) Expert Panel has deemed OCTOXYNOL-8 safe for use in rinse-off products and in leave-on formulations at concentrations not exceeding 5%, with this assessment reaffirmed in a draft report dated September 2025. While the FDA permits octoxynols as indirect food additives, it is critical to note that the European Chemicals Agency (ECHA) classifies Octoxynol ingredients as 'substances of very high concern' due to identified aquatic toxicity, necessitating authorization for their cosmetic applications within Europe. This regulatory divergence and potential for increased skin absorption of shorter-chain octoxynols warrant careful consideration.

Your Skin

Skin Compatibility

Yes Normal
No Dry
Yes Oily
No Sensitive
Irritancy Unknown
Comedogenicity Unknown

Our Assessment

Verdict

Questionable

Despite CIR's safety assessment for specific uses and concentrations, the designation of OCTOXYNOL-8 by ECHA as a 'substance of very high concern' due to environmental toxicity significantly complicates its global viability and raises concerns for precision skincare applications, leading to a questionable overall rating.

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