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Moumoujus

BUTOXYETHANOL.

Questionable CAS 111-76-2 / FRAGRANCE, SOLVENT, VISCOSITY CONTROLLING

A dual-natured solvent with both water-loving and oil-loving properties that effectively dissolves various cosmetic ingredients while reducing product viscosity. Its amphiphilic structure enables it to enhance the penetration of other active ingredients through the skin barrier, though this same property raises concerns about its safety profile.

Summary

solvent viscosity controlling fragrance ingredient penetration enhancer

Science

Mechanism of Action

Functions as a multifaceted solvent by utilizing its unique molecular structure containing both hydrophilic ether groups and lipophilic butyl chains. This allows it to solubilize diverse substances, reduce formulation viscosity, and act as a penetration enhancer by increasing ingredient flux through the stratum corneum while simultaneously degreasing the skin's natural lipid barrier.

Research

Clinical Evidence

Medium confidence
Effective range 5–10%
Optimal

10%

Key findings

  1. 01 HRIPT study (n=201) demonstrated non-sensitizing properties at 10% concentration with 7% of subjects showing mild erythema reactions
  2. 02 Penetration studies revealed 50% aqueous solutions increase skin permeation by 6-fold compared to undiluted solvent
  3. 03 Dermal absorption studies in hair dye formulations showed 12.1-12.5% absorption rate of applied dose at 5-10% concentrations

Transparency

Dusting Analysis

Not commonly dusted

Primarily used as a functional solvent rather than an active ingredient, making dusting less relevant for this component

The Formula

Formulation

Solubility
Both
Optimal pH 5.5 – 13.5
0 7 14

Stability

Demonstrates exceptional stability across wide pH spectrum from acidic to highly alkaline conditions. Semi-volatile nature and universal miscibility with water and organic solvents provides formulation flexibility.

Conflicts

  • Strong oxidizing agents
  • Strong acids (ester formation risk)
  • Aldehydes (acetal formation)
  • Long-term storage concerns due to potential explosive peroxide formation

Safety

Safety Profile

CIR Status
Insufficient data
Max tested
10%
Sensitization risk Low

CIR Panel's 2025 amended report reversed previous safety approval due to European Commission restrictions. Originally deemed safe up to 10% in hair/nail products, but current data considered insufficient for comprehensive safety determination in cosmetic applications.

Your Skin

Skin Compatibility

Yes Normal
No Dry
Yes Oily
No Sensitive
Irritancy Moderate
Comedogenicity Low

Our Assessment

Verdict

Questionable

While functionally effective as a solvent and penetration enhancer, the recent reversal of safety approval and insufficient data designation make this ingredient problematic for precision skincare formulations.

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