This synthetic polymer serves as a high-performance emollient and waterproofing agent, offering a non-greasy, silky skin feel. Formulators frequently utilize it to enhance product spreadability and provide a long-lasting moisture barrier without the heaviness associated with traditional oils.
- INCI Name:
- Hydrogenated Polyisobutene
- Chemical/Scientific Name:
- Hydrogenated poly(1-propene, 2-methyl)
- Common Aliases:
- Liquid Isoparaffin, Hydrogenated Polyisobutylene
| Category: | Softeners |
| Source Origin: | Synthetic |
| Comedogenic Rating: | 1 |
| Primary Industries: | Cosmetics, Personal Care, Pharmaceuticals |
| Solubility: | Lipophilic (Oil-soluble) |
At a Glance: Properties & Effects
| Hydration/Moisture | |
| Texture Enhancement | |
| Irritation Risk |
Primary Benefits:
- Provides a significant occlusive barrier to prevent transepidermal water loss.
- Improves the “slip” and application feel of heavy creams and ointments.
- Enhances the longevity and water-resistance of sunscreens and color cosmetics.
- Acts as a stable, non-oxidizing alternative to natural oils and Squalane.
Potential Risks:
- Minimal risk of irritation; generally considered non-sensitizing even at high concentrations.
- May feel slightly filmed or heavy if used in excessively high ratios within a formula.
Biological Action & Cosmetic Profile
Preventing transepidermal water loss (TEWL) is the primary physiological function of this ingredient. It functions as an occlusive emollient by creating a thin, hydrophobic film over the stratum corneum. This physical barrier traps moisture within the skin layers, which is particularly beneficial for compromised or extremely dry skin types. Unlike many vegetable oils, its saturated hydrocarbon structure makes it highly resistant to oxidation, ensuring the product remains stable on the skin surface for extended periods.Excellent pigment wetting properties make it a staple in decorative cosmetics. It allows for a higher load of pigments in foundations and lipsticks while maintaining a smooth, uniform texture. By reducing the surface tension of the oil phase, it ensures that colorants are evenly dispersed, preventing streaking or clumping during application. In hair care, it provides a conditioning effect by smoothing the cuticle and adding gloss without the volatility issues associated with certain silicones.
Broader Applications & Origins
Manufactured through the controlled polymerization of isobutene followed by hydrogenation, this ingredient results in a clear, odorless liquid. Its molecular weight can be adjusted during synthesis to produce varying viscosities, ranging from light oils to thick, gel-like substances. Because it is chemically inert, it does not react with other active ingredients, making it an ideal carrier for unstable compounds.Lip gloss formulations frequently rely on higher viscosity versions of this polymer to achieve a “wet look” and high-shine finish. It effectively replaces Mineral Oil or Petrolatum in “oil-free” claims while providing similar levels of protection and emolliency. Its ability to remain on the skin during perspiration or water exposure makes it a critical component in waterproof sunscreens.
Routine Integration
Synergies:
- Works exceptionally well with Dimethicone to create a multi-layered protective barrier.
- Combined with Caprylic Capric Triglyceride, it provides a balanced skin feel with both immediate and long-term emolliency.
- Often used alongside Tocopherol to enhance the spreadability of vitamin-rich oil serums.
- Frequently paired with Ethylhexyl Palmitate to adjust the absorption rate and finish of lotions.
Clinical Consensus & Safety
The Cosmetic Ingredient Review (CIR) Expert Panel has evaluated Hydrogenated Polyisobutene multiple times, concluding it is safe for use in cosmetic products at current concentrations. Clinical studies have shown it to be non-comedogenic and non-irritating to the eyes and skin. Because it is a large, branched-chain hydrocarbon, it does not penetrate the skin barrier into the bloodstream, remaining strictly on the surface where its functional benefits are required.
Is Hydrogenated Polyisobutene the same as mineral oil?
While both are hydrocarbons, they are chemically distinct. Hydrogenated Polyisobutene is a synthetic polymer often used as a more sophisticated alternative to Mineral Oil because it can be engineered for specific viscosities and offers a lighter, more elegant skin feel.
Will this ingredient cause acne or clogged pores?
It is rated very low on the comedogenic scale (typically a 1). Most individuals with acne-prone skin tolerate it well, though those with extremely oily skin may prefer products with a lower concentration of occlusive agents.
Is it safe for use on the lips?
Yes, it is widely used in lip balms and glosses. Due to its high molecular weight and chemical stability, it is safe for incidental ingestion and provides an effective moisture barrier for the delicate skin of the lips.