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Moumoujus

PEG-8.

Valuable CAS 5117-19-1 / 25322-68-3 (generic) / HUMECTANT, SOLVENT

PEG-8 is a polyethylene glycol derivative that functions as a highly effective humectant, drawing and retaining moisture in the skin to enhance hydration. Its versatile nature also allows it to act as a solvent, emulsifier, and viscosity control agent, improving product texture and ingredient distribution.

Summary

humectant solvent solubilizer viscosity control agent emollient emulsifier

Science

Mechanism of Action

PEG-8 enhances skin hydration by forming hydrogen bonds with water molecules, thereby binding moisture to the skin's surface and minimizing transepidermal water loss. It acts as a solvent, facilitating the dissolution and uniform distribution of other cosmetic ingredients within a formulation, and can improve their penetration. Furthermore, PEG-8 modifies product consistency as a viscosity control agent, stabilizes immiscible phases as an emulsifier, softens the skin as an emollient, and helps prevent formulations from drying out or crystallizing.

Research

Clinical Evidence

Low confidence
Effective range N/A
Optimal

N/A

Transparency

Dusting Analysis

Not commonly dusted

The Formula

Formulation

Solubility
Water
Optimal pH 4 – 7.5
0 7 14

Stability

PEG-8 demonstrates stability across a pH range of 4.0-7.5 and is resistant to moderately strong acids, alkalis, and salt solutions. Aqueous solutions maintain stability at room temperatures without hydrolysis of PEG bonds. It dissolves effectively in warm water (80-90°C). However, it is susceptible to oxidative degradation when exposed to air, with accelerated aging under warm temperatures, light, and oxygen. Optimal stability can be achieved by storing solutions frozen or refrigerated, purging oxygen with argon, and protecting from light.

Conflicts

  • Phenol (may reduce antimicrobial action)
  • Penicillin (rapidly inactivated)
  • Bacitracin (rapidly inactivated)
  • Sorbitol
  • Tannic acid
  • Salicylic acid
  • Certain plastics (may affect integrity)
  • Damaged or broken skin

Safety

Safety Profile

CIR Status
Safe as used
Max tested
85%
Sensitization risk Moderate

The Cosmetic Ingredient Review (CIR) Expert Panel deemed PEG-8 safe for use in cosmetics at concentrations up to 85%. Both the Scientific Committee on Consumer Safety (SCCS) and the FDA consider trace amounts of 1,4-dioxane, a potential manufacturing byproduct, to be non-hazardous in cosmetic applications. However, a significant caveat exists: PEG-8 is not recommended for use on damaged or broken skin due to historical evidence of kidney damage in burn patients treated with PEG-based antimicrobial preparations. It has been identified as a mild sensitizer and irritant in clinical studies.

Your Skin

Skin Compatibility

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

Our Assessment

Verdict

Valuable

PEG-8 is a valuable, multifunctional ingredient in cosmetic formulations, praised for its humectant, solvent, and emulsifying properties, though its application should be strictly avoided on damaged or broken skin due to safety considerations.

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