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Capryleth-4.

Valuable CAS 27252-75-1 / SURFACTANT - CLEANSING, SURFACTANT - EMULSIFYING

Capryleth-4 is a versatile non-ionic surfactant and emulsifying agent derived from capryl alcohol and ethylene oxide. It excels at bridging the gap between oil and water, making it a foundational component for creating stable, lightweight emulsions and effective rinse-off cleansing systems.

surfactant cleansing agent emulsifier solubilizer

Science

As an amphiphilic molecule, Capryleth-4 works by lowering the surface tension of liquids, allowing water to mix with oil and debris. Its lipophilic C8 chain attaches to sebum and impurities, while its hydrophilic PEG-4 head remains attracted to water, effectively lifting and suspending contaminants so they can be easily rinsed away without disrupting the skin barrier.


Research

High confidence
Effective range 0.1–5%
Optimal

2.5%

Key findings

  1. 01 Clinical human repeat insult patch tests (HRIPT) confirm that at concentrations between 0.5% and 5%, Capryleth-4 exhibits no significant sensitization or irritation potential.
  2. 02 Comparative safety assessments by the CIR indicate that while undiluted alkyl PEG ethers may cause mild irritation, they are benign when formulated within standard cosmetic usage ranges.

Transparency

Not commonly dusted
Min. effective
0.1%
Red flag below
0.05%

Because it is a functional emulsifier rather than an active 'hero' ingredient, it is rarely marketed with misleading claims. However, if used below 0.1% in a cleanser, it is likely not contributing meaningfully to the formula's surfactant system.


The Formula

Solubility
Both
Optimal pH 3 – 11
0 7 14

Stability

Exhibits exceptional stability across a broad pH spectrum due to its non-ionic nature. It is highly resistant to hydrolysis and maintains performance in the presence of various electrolytes.

Synergies

  • Anionic surfactants
  • Cationic conditioning agents
  • Glycerin

Conflicts

  • Phenolic preservatives
  • Strong oxidizing agents

Safety

CIR Status
Safe as used
Max tested
25%
Pregnancy
Safe
Sensitization risk Low

The CIR Expert Panel considers this ingredient safe when formulated to minimize irritation; it is typically used far below the 25% safety ceiling in precision skincare.


Your Skin

Yes Normal
Yes Dry
Yes Oily
Yes Sensitive
Irritancy Low
Comedogenicity Low

Our Assessment

Valuable

A reliable and gentle formulation workhorse that ensures product stability and effective cleansing without compromising the skin's moisture barrier.


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