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Moumoujus

BETA-SITOSTERYL COPOLYMER.

Valuable CAS 1013637-82-5 / FILM FORMING

A high-performance hybrid ingredient that bridges the gap between advanced film-forming polymers and bio-mimetic skin lipids. It provides a sophisticated, breathable shield that simultaneously reinforces the skin's physical barrier while ensuring long-lasting hydration and product wearability.

Summary

Film Former Barrier Repair Skin Conditioning Emollient

Science

Mechanism of Action

This copolymer utilizes an Octadecene/MA backbone to create a flexible, water-resistant matrix on the skin's surface. Within this matrix, esterified beta-sitosterol—a plant-derived sterol—integrates directly into the stratum corneum's lipid bilayer, mimicking the skin's natural architecture to prevent transepidermal water loss (TEWL) and soothe inflammation.

Research

Clinical Evidence

Medium confidence
Effective range 0.5–5%
Optimal

2%

Key findings

  1. 01 Comparative data demonstrates that the beta-sitosteryl moiety significantly enhances barrier integration and TEWL reduction over standard non-esterified polymers.
  2. 02 Clinical observations of phytosterols show measurable improvements in barrier repair and a reduction in inflammatory markers at concentrations between 1.0% and 2.0%.

Transparency

Dusting Analysis

Not commonly dusted
Min. effective
0.5%
Red flag below
0.25%

As a specialty technical polymer often used for functional texture and barrier support, it is rarely 'dusted' for marketing. However, concentrations below 0.5% may fail to provide the characteristic film-forming and water-resistance benefits.

The Formula

Formulation

Solubility
Oil
Optimal pH 4 – 8.5
0 7 14

Stability

The molecule is highly heat-stable and resistant to oxidation due to its saturated chemical structure. It should be incorporated into the oil phase of emulsions.

Synergies

  • Ceramides
  • Fatty Acids
  • Mineral UV Filters

Conflicts

  • pH levels exceeding 9.0 (risk of ester hydrolysis)
  • Extreme electrolyte concentrations in aqueous gels

Safety

Safety Profile

CIR Status
Components reviewed and safe
Max tested
5%
Pregnancy
Safe
Sensitization risk Low

While the specific copolymer is a newer cosmetic innovation, its constituent parts (Beta-Sitosterol and Octadecene/MA Copolymer) have established safety profiles and are well-tolerated.

Your Skin

Skin Compatibility

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

Our Assessment

Verdict

Valuable

An exceptional multi-functional ingredient that provides both immediate environmental protection and long-term lipid barrier reinforcement.

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