--- title: "Summer Sun Protection: Guarding Against Invisible Light and Invisible Microbes" description: How do we ensure robust microbial protection in sunscreen formulations? As summer arrives, sunscreen becomes an outdoor essential. However, did you know that a qualified sunscreen must do more than url: https://www.dmcostech.com/blog/summer-sun-protection-guarding-against-invisible-light-and-invisible-microbes markdown_url: https://www.dmcostech.com/blog/summer-sun-protection-guarding-against-invisible-light-and-invisible-microbes.md type: post slug: summer-sun-protection-guarding-against-invisible-light-and-invisible-microbes author: dmcostech published: 2026-01-23T08:36:26Z modified: 2026-01-23T08:36:29Z language: en-US taxonomies: category: - Ingredients Introduction word_count: 905 tokens: 1822 --- # Summer Sun Protection: Guarding Against Invisible Light and Invisible Microbes How do we ensure robust microbial protection in sunscreen formulations? As summer arrives, sunscreen becomes an outdoor essential. However, did you know that a qualified sunscreen must do more than just block UV rays? It must also pass a critical hidden test: microbial protection. From formula design to production and filling, invisible microorganisms are a constant threat. A momentary lapse can compromise product safety and stability. Today, we delve into the “preservation secrets” behind high-quality sunscreen products. Why is Preserving Sunscreen So Difficult? Sunscreen products are classified as special-use cosmetics (in many regions). To successfully register them, every step—from formulation design to filing and production—requires meticulous attention. Microbial protection in sunscreens presents significantly greater challenges than in ordinary skincare products. Why is the preservation challenge so high for sunscreens? High Oil Phase Proportion: Generally, the higher the SPF, the higher the proportion of the oil phase in the formula. Traditional preservatives are often difficult to dissolve in water and easily migrate into the oil phase. This leads to insufficient concentration in the water phase (where bacteria grow), compromising preservation efficacy. Interference from Polar Oils: To dissolve solid organic sunscreen agents, formulas often include polar oils. These ingredients tend to “drag” oil-soluble preservatives into the oil phase, further reducing preservation efficiency in the water phase. Powder Adsorption: Physical sunscreen agents utilize powders (such as Titanium Dioxide and Zinc Oxide) with large specific surface areas. These powders can adsorb preservatives, reducing the amount of active preservative available to fight microbes. This explains why some sunscreens fail preservation challenge tests despite containing high levels of preservatives—it’s not that not enough was added, but that the active agents were “migrated out” or “adsorbed.” From “Traditional Preservation” to “Multifunctional Ingredients” The Secrets Behind Ingredient Evolution The “protagonists” of sunscreen preservation have quietly changed over the years. In the past, formaldehyde releasers, parabens, and halogenated compounds were mainstream; a mere 0.1% addition was often sufficient. However, as consumer demand for “gentle” and “non-irritating” products has risen, the application of these ingredients has declined. Additionally, many sunscreen agents require a neutral pH, which renders many organic acid preservatives ineffective against fungi. Consequently, alcohols and multifunctional additives have become market favorites. These include Phenoxyethanol, Ethylhexylglycerin, Caprylyl Glycol, and Pentylene Glycol. While their total addition levels often exceed 1%, the challenge lies in creating a cost-effective, gentle combination. In this regard, euxyl™ pe 9010 (a combination of Phenoxyethanol + Ethylhexylglycerin) is known as a “Golden Partner.” Ashland was the first enterprise to discover that this combination possesses a [1+1>2] preservation efficacy. The Mechanism: Ethylhexylglycerin acts as a “booster,” affecting the interfacial tension at the cell membrane of microorganisms, allowing Phenoxyethanol to penetrate more effectively. The Result: The antibacterial effect is far greater than the sum of its parts. This allows for a lower dosage of Phenoxyethanol (reducing potential irritation) while boosting preservation power. Mintel data shows that this combination appears frequently in new sunscreen launches from major international brands, holding the top spot in both Global and Asia-Pacific markets. A Common Client Question: “How is Ashland’s euxyl™ pe 9010 different from other similar combinations on the market?” The critical difference lies in the quality of the raw materials. euxyl™ pe 9010 is composed of Phenoxyethanol + sensiva™ sc 50. The sensiva™ sc 50 (Ethylhexylglycerin) includes a small amount of Tocopherol (Vitamin E) as a stabilizer. This ensures that even after 3 years of storage, no impurities appear, guaranteeing high purity and stability. Tailored Preservation Solutions for Different Sunscreen Formats Sunscreen comes in various forms, from bi-phase “shake” lotions and high-SPF creams to children’s formulas and compact powders. The preservation strategy must be “tailor-made.” “Shake-to-Mix” Sunscreen (Water-in-Oil / W/O): Whether pure physical or hybrid (physical + chemical) UV filters are used, adding 0.6% euxyl™ pe 9010 allows the formula to pass rigorous preservation testing (Criteria A) with excellent stability. High Protection Sunscreen (SPF50, PA+++): A combination of 0.6% euxyl™ pe 9010 + 0.2% sensiva™ sc 10 (Caprylyl Glycol + Ethylhexylglycerin) + 0.2% Hydroxyacetophenone. This blend protects against bacteria and inhibits fungi, easily passing challenge tests. Children’s Sunscreen: Uses euxyl™ pe 9010 (0.8%) + sensiva™ sc 10 (0.3%). This combination balances gentleness with broad-spectrum protection against both bacteria and fungi. Sunscreen Powder Compact: Using just 1% sensiva™ sc 10 (Caprylyl Glycol + Ethylhexylglycerin) ensures preservation efficacy while allowing for “Preservative-Free” claims, meeting the consumer demand for minimalist formulations. Sunscreen Lotions/Milks: Three customer-validated combinations: euxyl™ pe 9010 + Pentylene Glycol euxyl™ pe 9010 + sensiva™ sc 10 Pentylene Glycol + Raspberry Ketone A Featured Antimicrobial Ingredient: phyteq™ raspberry multifunctional (Raspberry Ketone) This ingredient is worth special attention. Not only does it provide antimicrobial properties (with outstanding efficacy against fungi), but it also offers soothing and antioxidant benefits. An addition of 0.3% – 0.5% can synergize with other ingredients to boost efficacy. It is highly suitable for sensitive skin and is frequently found in commercially available high-SPF products. Want to Perfect Your Sunscreen Preservation? DMCOS Offers Professional Support! The preservation design of sunscreen formulas requires professional testing and R&D support. DMCOS provides a one-stop service: Preservation Challenge Testing: We simulate microbial contamination risks during production and storage to verify formula safety. Formula R&D: We customize preservation solutions based on your needs—whether you need to reduce irritation or pursue “Preservative-Free” claims. Technical Support: From factory hygiene inspections to training on testing methods, we protect your process from start to finish. Summer Tip: When choosing a sunscreen, don’t just look at the SPF value. A reliable sunscreen is backed by meticulous microbial protection logic—blocking the sun while stopping invisible microbes. We believe the ingredients recommended above will become the “pillars” of your product line’s safety.