Best SPF Boosters for Zinc Oxide formulas? Methylcellulose, Styrene/Acrylates Copolymer ++
I’m investigating SPF Boosters, non-drug ingredients that either help disperse the actives on the skin, form films, scatter light or actually absorb UV radiation. The formula in question is for now a simple oil in water emulsion with Caprylic/Capric Triglycerides, Ewax NF (or Olivem 1000 or similar), a Zinc Oxide Jojoba Ester, Polyhydroxystearic Acid dispersion, some humectants, gum, antioxidants and preservative. Possibly also film formers like Candelilla wax.
Methylcellulose sold under the Solterra brand: http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_08b5/0901b803808b5946.pdf?filepath=suncare/pdfs/noreg/324-00321.pdf&fromPage=GetDoc
20% Zinc Oxide formula gets SPF39 with 2% of it and SPF33 with 1%, doesn’t seem impressive and could this effect just be attributed to the gel forming and be emulated by other gelling thickeners?
SunSpheres™ Powder Styrene/Acrylates Copolymer claims it helps scatter light.
What else should I look into?