This polymeric UV filter serves as a robust shield against UVB radiation while imparting a sophisticated, silky texture to cosmetic formulations. High molecular weight ensures the substance remains on the skin surface, significantly minimizing the potential for irritation or systemic absorption compared to smaller organic filters.
- INCI Name:
- Polysilicone-15
- Chemical/Scientific Name:
- Dimethicodiethylbenzalmalonate
- Common Aliases:
- Parsol SLX
| Category: | Sun Protection |
| Source Origin: | Synthetic |
| Comedogenic Rating: | 0 |
| Primary Industries: | Skin Care, Hair Care |
| Solubility: | Oil and Silicone Soluble |
At a Glance: Properties & Effects
| UVB Protection: | |
| Texture Enhancement: | |
| Formula Stability: | |
| Irritation Risk: |
Primary Benefits:
- Provides effective UVB absorption (290–320 nm).
- Reduces the greasy or “tacky” feel of other oil-soluble UV filters.
- Protects hair protein and color from degradation caused by sun exposure.
- Demonstrates exceptional photostability and does not degrade rapidly under light.
Potential Risks:
- Offers minimal protection against long-wave UVA radiation.
- Not currently approved as an active sunscreen ingredient in the United States by the FDA.
Biological Action & Cosmetic Profile
The functionality of this ingredient stems from its unique polymeric structure, where chromophores—specifically benzylmalonate groups—are chemically attached to a polydimethylsiloxane (silicone) backbone. Unlike traditional monomeric UV filters, this “silicone-plus-filter” hybrid occupies a large molecular volume. This size prevents the molecule from penetrating the stratum corneum, ensuring that the UV-absorbing action remains exclusively on the skin’s surface where it is most effective and least likely to cause biological interference.
Photoprotection is achieved through the absorption of high-energy UVB photons, which the molecule converts into harmless heat energy. Because it is a liquid silicone, it integrates seamlessly into the lipid phase of an emulsion, acting as a solvent for other solid UV filters like Butyl Methoxydibenzoylmethane. This solubility helps prevent the recrystallization of other actives, thereby maintaining the uniformity and efficacy of the sun protection film across the skin.
Broader Applications & Origins
Hair care formulations utilize this silicone-based filter more frequently than many other UV absorbers. It deposits easily onto the hair shaft, creating a hydrophobic barrier that shields keratin from oxidative stress and prevents the “fading” of synthetic hair dyes. Its non-stick finish makes it an ideal addition to leave-in conditioners and heat-protectant sprays where traditional sunscreens would feel too heavy or oily.
In global markets, the ingredient is a staple in high-performance sunscreens across Europe and Asia. Its development was a response to the cosmetic industry’s need for a filter that could bridge the gap between effective photoprotection and the sensory elegance required for daily-wear facial moisturizers.
Routine Integration
Synergies:
- Works exceptionally well with Butyl Methoxydibenzoylmethane (Avobenzone) to enhance overall photostability.
- Often combined with Octocrylene or Ethylhexyl Triazone to reach higher SPF values.
- Pairs effectively with mineral filters like Titanium Dioxide to improve the spreadability of inorganic particles.
Conflicts:
- No known chemical conflicts; however, it should not be relied upon as the sole UV filter if broad-spectrum (UVA) protection is required.
Clinical Consensus & Safety
Regulatory bodies, including the European Scientific Committee on Consumer Safety (SCCS), have evaluated Polysilicone-15 and deemed it safe for cosmetic use at concentrations up to 10%. Clinical studies published in dermatological journals highlight its extremely low sensitization potential, attributing this to the molecule’s inability to penetrate the skin barrier. While it is widely approved in the EU, Australia, and many Asian countries, it remains categorized as a cosmetic ingredient rather than an active drug in certain regions, which dictates how it is listed on product labels.
Is Polysilicone-15 safe for sensitive skin?
Yes, it is considered one of the most skin-friendly chemical UV filters. Due to its large molecular size, it cannot be absorbed into the skin, which significantly reduces the risk of the allergic contact dermatitis often associated with smaller UV-absorbing molecules.
Does this ingredient provide full sun protection?
No, it primarily filters UVB rays, which are responsible for sunburn. To achieve broad-spectrum protection against UVA rays (responsible for aging), it must be used in conjunction with UVA filters like Zinc Oxide or Butyl Methoxydibenzoylmethane.
Can I find this ingredient in US sunscreens?
While you may find it in US-marketed hair care or makeup products for its “protective” properties, it cannot be listed as an active SPF ingredient in the United States because it has not yet been cleared through the FDA’s Sunscreen Innovation Act OTC monograph process.