Formulation Feedback

Your goal is to create a light, serum-like physical sunscreen with SPF 50 PA+++, water resistance, oil absorption, slight coverage, and some beneficial skincare actives. The combination of ingredients you've selected aims to achieve these properties.

Emulsifier System

You are proposing a complex system using Light Lotion Maker, Silicone Gel (Ultra Clear), Dimethicone 1Secs, and Pro Polymer™.

• Light Lotion Maker is an emulsifier suitable for creating light textures and can work in both hot and cold processes. It is designed to emulsify oils.
• Silicone Gel (Ultra Clear) and Dimethicone 1Secs are silicone-based ingredients that contribute to a smooth, light, non-greasy feel and aid in spreadability. Dimethicone 1Secs is volatile, providing a quick-drying sensation.
• Pro Polymer™ is a water-phase thickener that creates a gel texture in the water portion of a formula.

The physical sunscreen actives, Titanium Dioxide 15nm Liquid and Zinc Oxide 35nm Liquid, are specifically developed for water-in-oil (W/O) emulsion systems. Light Lotion Maker can function as a W/O emulsifier. Combining an oil/silicone phase emulsifier (Light Lotion Maker) with silicone emollients (Silicone Gel, Dimethicone 1Secs) and a water-phase thickener (Pro Polymer™) can potentially create a stable, lightweight emulsion, possibly a W/Si (water-in-silicone) or a complex W/O system with a thickened external water phase. This approach can help achieve the desired light, serum-like feel while incorporating the oil-soluble/dispersible components and the water-soluble actives. However, the interaction between the water-soluble Pro Polymer™ and the oil/silicone phase, as well as the stability of the emulsion type formed, will require careful formulation and testing.

Color Adjustment

You asked about the percentage of Beige Iron Oxides EasyMix™ for different skin tones.

• 0.3% Beige Iron Oxides EasyMix™ will likely provide a very sheer tint suitable only for very fair skin tones or for slightly adjusting the base color without significant coverage.
• To achieve a range of shades for different skin tones, you will need to adjust the percentage of Beige Iron Oxides EasyMix™ and incorporate other Iron Oxides EasyMix™ pigments, specifically Yellow, Red, and Black.
• The product description for Beige Iron Oxides EasyMix™ provides example ratios for different shades (No. 1, No. 2, No. 3) by combining Beige, Yellow, Red, and Black Iron Oxides with Titanium Dioxide. These examples demonstrate that a single color pigment is not sufficient for a universal tint; blending is necessary to match various complexions. You will need to experiment with the ratios of these pigments to create the desired shades and coverage levels.

Other Ingredients

• SelectSorb™ and QuikBlur™ are good choices for oil absorption, reducing shine, and providing a blurring effect, contributing to a smooth, matte finish suitable for a lightweight serum.
• WaterGuard™ Spray is a film-former for water resistance. Note that this ingredient is soluble in alcohol. Its compatibility and effectiveness in your specific base formulation (which may not contain significant alcohol) should be verified.
• The combination of Titanium Dioxide 15nm Liquid and Zinc Oxide 35nm Liquid at 10% and 10% respectively, along with 5% PMMA Booster, should provide robust broad-spectrum UV protection to achieve SPF 50 PA+++. PMMA Booster is known to enhance SPF/PA values.
• The nourishing and antioxidant ingredients (Squalane, Safe-B3™ (Niacinamide), ActiveProtec™ UV, Ethyl Ferulate, Magnesium Ascorbyl Phosphate, Calcium Pantothenate, Coenzyme Q10) add beneficial properties. However, be mindful of potential pH compatibility issues, particularly between Niacinamide (optimal pH 4.0-7.0) and Magnesium Ascorbyl Phosphate (optimal pH 7-9 for stability). You may need to adjust the final pH or consider alternative forms or delivery systems for these actives to ensure their stability and efficacy.
• The preservation system (1,2-Hexanediol, Mild Preserved Eco™, Disodium EDTA) seems appropriate. However, the description for Titanium Dioxide 15nm Liquid notes that it cannot be used in formulas containing electrolytes because its dispersion emulsifier is sensitive to them. Disodium EDTA is an electrolyte source and could potentially cause instability issues with the Titanium Dioxide dispersion. This interaction should be carefully tested.

Conclusion

The proposed formulation has the potential to create a lightweight, waterproof physical sunscreen serum with added skincare benefits. The emulsifier system is complex but could yield the desired texture with careful formulation. Achieving different skin tones will require blending multiple Iron Oxide pigments. Pay close attention to the potential pH incompatibility of Niacinamide and Magnesium Ascorbyl Phosphate and the potential instability of the Titanium Dioxide dispersion in the presence of electrolytes like Disodium EDTA. Thorough testing of the final formulation for stability, SPF/PA efficacy, water resistance, and sensory properties is highly recommended.