Octisalate vs Zinc Oxide: which is worse?

What is Octisalate?

Octisalate (INCI: Ethylhexyl Salicylate) is an oil-soluble UVB-absorbing chemical sunscreen active. It is primarily used as a UVB filter and photostabilizer for avobenzone.

What is Zinc Oxide?

Zinc oxide is an inorganic mineral UV filter and skin protectant that provides broad-spectrum UVA and UVB protection by reflecting and scattering UV radiation. It is also an FDA-approved OTC active for diaper rash, minor skin irritation, and sunburn treatment.

Documented risks

Octisalate: Octisalate is FDA-approved at up to 5% and EU-permitted at up to 5%. It has a good safety record and low sensitization rate. The 2019 FDA absorption study detected systemic absorption above the 0.5 ng/mL threshold, warranting further study. This does not indicate known harm. It is a salicylate; those with aspirin sensitivity should note the structural relationship, though reactions are rare.

Zinc Oxide: Bulk zinc oxide used in traditional formulations has an excellent safety record. The primary concern is nanoparticle zinc oxide (nano-ZnO) used in transparent sunscreen formulations: the EU has reviewed nano-ZnO and found it safe for use in non-spray sunscreens (SCCS opinion 2022), but restricted it in spray products due to inhalation risk. Nano-ZnO does not penetrate intact skin. Zinc oxide is non-carcinogenic, non-hormone-disrupting, and reef-safer than chemical filters.