The Verdict List

Ingredient glossary

Use with caution

Zinc oxide

Last reviewed

Researched & reviewed by The Verdict List Editorial Team

What it is

Zinc oxide is a mineral compound and the FDA-recognized active ingredient in most diaper-rash ointments and mineral sunscreens; it forms a physical barrier on skin and has a long safety record at the concentrations those products use. The ingredient itself is not the concern in this review; the concern is contamination reported in particular finished products. Zinc oxide is refined from zinc ore, and trace metals can be present as impurities, but a finished-product test alone does not identify the ingredient or processing step that introduced them.

Why it's flagged

Independent testing of zinc-oxide-containing products has produced repeated product-specific detections. Between mid-2025 and early 2026, an independent ICP-MS testing initiative (Lead Safe Mama, using Purity Labs) reported lead, cadmium, arsenic, or mercury in multiple name-brand diaper-rash creams, including products marketed as "clean" or EWG Verified. Those reports do not establish that zinc oxide itself, a particular mine, or a supplier caused every finding. Lead and cadmium are treated as serious contaminants for children, but a concentration in a cream is not the same thing as an absorbed dose or a diagnosis. These product-specific results also do not by themselves establish a legal violation: FDA's cited 10-ppm document is draft cosmetic guidance, and Washington's Toxic-Free Cosmetics Act has scope and drug-product exclusions. See "how concerned to be" for what these numbers do and don't mean.

How concerned to be

Use with caution, and check the specific product before assuming "zinc oxide" alone tells you anything. Pharmaceutical- and cosmetic-grade zinc oxide from a reputable manufacturer can meet purity specifications, but the published product tests show why an ingredient name is not a substitute for finished-product evidence. FDA's 2016 document recommends no more than 10 ppm lead as an impurity in cosmetics; it is draft guidance, not a universal binding limit and it addresses cosmetic exposure assumptions. Washington's current page lists a 1-ppm lead restriction for cosmetics, while also saying the TFCA does not apply to FDA-regulated drug ingredients and that an interim policy remains in effect. Many diaper-rash products are labeled as OTC drug products, so classification and the product's full formula matter before calling a result illegal. A tested petrolatum-based balm was non-detect for lead, cadmium, mercury, and arsenic; that is evidence about that sample and an alternative formulation, not proof about every non-zinc product. See our diaper-rash-cream category page for product-by-product results.

What it's called on a label

Look for any of these on an ingredient list: ZnO, Zinc oxide.

Sources

  1. Heavy Metals in Cosmetics: A General Overview, U.S. Food and Drug Administration (2023)
  2. Zinc Oxide Monograph, United States Pharmacopeia, USP–NF (2024)
  3. Limiting Lead in Cosmetics (non-binding draft guidance, recommended maximum 10 ppm), U.S. Food and Drug Administration (2016)
  4. Toxic-Free Cosmetics Act (current scope, restrictions, and interim lead policy), Washington State Department of Ecology (2026)
  5. Independent, Third-Party Laboratory Testing of Zinc-Oxide Diaper Rash Creams and Ointments for Lead, Cadmium, Mercury, and Arsenic (Community-Collaborative Testing Initiative), Lead Safe Mama (Tamara Rubin) (2025)