Active ingredient

Zinc Oxide

INCIZinc Oxide (micronized grades labeled Zinc Oxide [nano] per EU 1223/2009 Art. 19)

up to 20% (baby diaper rash cream)Typical concentration

Last reviewed by BIOSAR Scientific Team, PharmD, Cosmetic Chemistry, Pharmacy practice on April 28, 2026.

What it is

Zinc oxide is a mineral UV filter used in sunscreen and photoprotective skincare to reflect and scatter UVB and the full UVA spectrum. It offers the broadest single-filter UVA coverage available in cosmetic formulations and remains chemically inert on the skin surface. Effective at 5% to 25% across cosmetic SPF formulations; often paired with titanium dioxide for layered photoprotection. Suitable for sensitive and post-procedure skin. No conflicts.

Pregnancy and breastfeeding

Safe

Considered safe during pregnancy and breastfeeding.

Mineral UV filters zinc oxide and titanium dioxide remain on the skin surface and are not systemically absorbed. ACOG, Mother to Baby, and Trivedi et al. (2017) recommend mineral sunscreens during pregnancy.

Mechanism in detail

What Zinc Oxide does

Mineral UV filter and skin-protectant oxide. It reflects UVA and UVB across a broad spectrum and forms a calming, protective layer — the reason it works both in sunscreens and in soothing diaper-area care.

Evidence

What the research says

→400 nmFull-spectrum shield, all the way to long-wave UVAIn FDA-method testing, microfine zinc oxide attenuated across the entire UV range, including long-wave UVA I out to 400 nm. It stayed photostable and non-reactive, delivering steady broad-spectrum defense.Read the study →J Am Acad Dermatol 1999 (Mitchnick)

From the BIOSAR catalog