From Protection to Complexion: Formulating Zinc Oxide Into SPF Makeup Bases

• Dispersion of zinc oxide through the oil phase, with no clumps, is the most important factor. It gives you both the SPF rating and a clean finish with no white cast. Poor dispersion loses both.

• ZinClear® XP grade is selected by BET surface area. Five grades run from 15 to 40 m²/g. Higher surface area gives more UV attenuation per gram and higher oil demand, so the grade sets the balance between protection and skin feel.

• ZinClear® XP supports formulation across deep skin tones. Tight particle-size distribution and full dispersion in the oil phase hold visible-light scattering low, so shade accuracy carries through the dark end of a foundation range rather than breaking down there.

• ZinClear® XP is uncoated and non-nano. Nothing sits between the zinc oxide and the colour pigments, so the shade stays even and consistent batch to batch.

• Finalise the pigment shade before SPF testing. Any change afterwards cancels the SPF result and means testing again.

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Locking the Pigment Phase Before SPF Testing

SPF is substantiated on the finished, as-sold product under ISO 24444, not on active concentration. Two variables set the measured figure. Application thickness is lower for a makeup base than the 2 mg/cm² sunscreen reference, which caps the total filter present on skin. Pigment interaction is the second: the size and distribution of the iron oxides in the film shift UV attenuation up or down.

The consequence is procedural. Any change to the pigment phase after testing, whether a shade extension, a cost reformulation or a raw material substitution, invalidates the SPF claim and forces a re-test. Finalising the full pigment phase before commissioning ISO 24444 is the most reliable way to avoid a repeat panel on an SPF makeup base.

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Selecting the Right ZinClear® XP Grade

Loading, shade accuracy and emulsion stability all resolve into one specification decision: the grade of zinc oxide the formula is built on. ZinClear® XP is a pharmaceutical-grade, uncoated, non-nano zinc oxide (200 to 700 nm particle size, at least 98% zinc oxide purity), supplied in five grades separated by BET surface area from 15 to 44 m²/g. Surface area is the practical selection lever: higher BET means greater UV efficiency per gram and higher oil demand. For a complexion base the trade-off is UV performance against oil demand and skin feel:

• BET 15 to 19 m²/g: lowest oil demand, easiest to disperse. Suited to daily SPF moisturisers and light tinted skincare where a light film and simple processing take priority.

• BET 20 to 29 m²/g: stronger UV performance with good transparency and reliable batch-to-batch SPF. A practical range for tinted moisturisers and BB creams balancing skin feel against dependable broad-spectrum coverage.

• BET 35 to 44 m²/g: highest UV efficiency per gram. Suited to mineral makeup, pressed powders and foundation systems where maximum protection per point of active is required and the base can carry the higher oil demand.

  
  

ZinClear® XP is available as powder and as pre-dispersions in carrier oils. In powder form the particles agglomerate when dry and are broken down under high-shear mixing, which gives the formulator direct control over final dispersion and SPF. Pre-dispersions arrive with that step complete and stabilised in oil, ready to incorporate on standard equipment. Both deliver equivalent protection, so the choice follows manufacturing capability rather than performance.

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Shade Accuracy Across a Tonal Range

Zinc oxide has a refractive index of 1.9 to 2.0 against roughly 1.4 for skin, and particles and agglomerates in the 200 to 500 nm range scatter visible light most efficiently. Conventional zinc oxide grades carry a wide particle-size and surface-area bandwidth, so a proportion of the material sits in that scattering range and lifts the apparent value of a shade inside a pigmented film. The effect is most visible in deeper shades, where any lightening is harder to correct and more closely scrutinised, which is why zinc oxide selection is tested first at the dark end of a foundation range rather than in the mid-tones used for internal work (Cosmetics & Toiletries, 2025).

ZinClear® XP is engineered against that behaviour. A proprietary micronisation and purification process holds a tight particle-size distribution and a narrow surface-area bandwidth batch to batch, so the material does not carry the coarse, variable fraction that drives visible scattering. Dispersed fully into the oil phase, it attenuates across 240 to 400 nm while staying transparent on skin, which is what allows a shade range to be extended into deep tones without the base lifting the finished colour.

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Requesting a Sample

Formulators and brand teams developing a tinted or base SPF product can request a ZinClear® XP sample to validate dispersion, transparency and UV performance in their own system. Grade recommendations for a specific pigment phase, emulsion type and carrier are available from the technical team on request. Advance ZincTek manufactures ZinClear® XP under TGA-licensed GMP conditions in Queensland, Australia.

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References

Advance ZincTek. (2024). ZinClear® XP product technical data. Available on request from advancezinctek.com.

Cole, C., Shyr, T., & Ou-Yang, H. (2016). Metal oxide sunscreens protect skin by absorption, not by reflection or scattering. Photodermatology, Photoimmunology & Photomedicine, 32(1), 5-10. https://doi.org/10.1111/phpp.12214

UL Prospector. (2022). Developing high-performing zinc oxide sunscreens using a technical modelling approach.

ISO 24444:2019. Cosmetics — sun protection test methods — in vivo determination of the sun protection factor (SPF).