Polyethylene acts as a structural backbone in anhydrous formulations, providing essential stability and a smooth sensory profile to sticks and balms. While its use as an abrasive in rinse-off scrubs has been largely discontinued due to environmental regulations, it remains a critical film former and thickener in leave-on makeup and skincare.
- INCI Name:
- Polyethylene
- Chemical/Scientific Name:
- Ethene homopolymer
- Common Aliases:
- Polythene, PE, Polyethylene Wax
| Category: | Texture Enhancers |
| Source Origin: | Synthetic |
| Comedogenic Rating: | 0 |
| Primary Industries: | Cosmetics, Pharmaceuticals, Food Packaging |
| Solubility: | Insoluble (Dispersible in hot oils/waxes) |
At a Glance: Properties & Effects
| Texture Enhancement: | |
| Formula Stability: | |
| Irritation Risk: | |
| Penetration Enhancement: |
- Primary Benefits: Increases the melting point of lipsticks, improves spreadability, creates a protective film, and ensures uniform pigment distribution.
- Potential Risks: Environmental persistence (microplastic concerns) and potential for “pilling” if used in excessive concentrations.
Biological Action & Cosmetic Profile
The molecular structure of this synthetic resin consists of long chains of ethylene monomers, which dictate its functional behavior in cosmetic chemistry. In its solid or powdered form, the polymer remains on the surface of the stratum corneum due to its high molecular weight, preventing any systemic absorption. Formulators utilize these chains to create a physical matrix within a product, which effectively traps liquid oils and prevents “bleeding” or “sweating” in lip products. By increasing the viscosity of the oil phase, it allows for a more consistent application and a “slip” that mimics the feel of high-end silicones like Dimethicone.
Beyond structural reinforcement, this ingredient functions as a robust film former. Once applied, it leaves a thin, non-greasy layer that helps to lock in moisture by reducing trans-epidermal water loss (TEWL), though it is less occlusive than traditional waxes or Petrolatum. In pressed powders and foundations, it acts as a binder, ensuring that Silica and pigments adhere to the skin without appearing chalky or settling into fine lines.
Broader Applications & Origins
Originally derived from the polymerization of ethylene gas—a byproduct of petroleum refining—this material is the most common plastic in global production. In the cosmetic industry, it has undergone a significant functional shift. For decades, spherical polyethylene “microbeads” were the industry standard for physical exfoliation. However, because these particles are non-biodegradable and bypass wastewater filtration systems, they have been banned in rinse-off products across the United States, European Union, and several other jurisdictions. Today, the cosmetic-grade version is almost exclusively used in leave-on formats where it exists as a wax or fine powder rather than a scrubbing bead.
Routine Integration
- Synergies: Pairs efficiently with Kaolin and Talc to improve the “payoff” of color cosmetics. It also stabilizes anhydrous balms containing Butyrospermum Parkii Butter by preventing graininess.
- Conflicts: No known biochemical conflicts; however, it may interfere with the “quick-break” sensation of certain water-light emulsions if the concentration is too high.
Clinical Consensus & Safety
The Cosmetic Ingredient Review (CIR) Expert Panel has repeatedly evaluated polyethylene, concluding it is safe for use in cosmetic formulations. Because the polymer is chemically inert and too large to penetrate the skin barrier, it lacks the potential for sensitization or toxicity. Clinical studies on rabbit models and human repeat insult patch tests (HRIPT) have consistently shown a lack of irritation. While safe for human skin, the regulatory focus remains on its environmental footprint. The European Union’s REACH regulation is currently phasing out “intentionally added microplastics,” which will eventually restrict this ingredient in leave-on skincare by 2029 and makeup by 2035 unless biodegradable alternatives are adopted.
Is polyethylene in skincare the same as plastic bags?
While they share the same chemical name, cosmetic-grade polyethylene is refined and processed into specific molecular weights and shapes (such as fine powders or soft waxes) to meet safety and sensory standards that differ significantly from industrial-grade plastics.
Will this ingredient clog my pores?
No. Polyethylene is non-comedogenic and chemically inert. It does not interact with sebum or penetrate the pore lining, making it suitable for acne-prone skin when used in foundations or sunscreens.
Are “microbeads” still used in face washes?
In most modern markets, including the US and UK, plastic microbeads are legally banned in rinse-off products. Most brands have replaced them with natural alternatives like jojoba esters, cellulose, or apricot seed powder.