Zi
Zinc Oxide (sunscreen)
Zinc OxideSPF filter
Mineral UV filter. Broadest-spectrum single filter available; physical sunscreen workhorse.
What it does
Zinc oxide reflects and absorbs UVA + UVB. The most reliably broad-spectrum mineral filter. Modern formulations grind it small enough to reduce the white cast historically associated with mineral SPF; nano-zinc remains a topic of formulation debate but is considered safe by most regulatory bodies.
The evidence, graded
moderateAntioxidants neutralize free radicals generated by the UV that gets through sunscreen. Layering an antioxidant serum under SPF compounds photoprotection.Wu 2011 · Clinical and Experimental Dermatology ↗
expert consensusSunscreen should sit as a film on top of moisturizer, not be mixed into it. Diluting sunscreen with moisturizer in your hand reduces filter concentration and the labeled SPF no longer applies.Petersen 2014 · Photodermatology, Photoimmunology & Photomedicine ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
Pairs worth knowing
Read more
Reading the evidence · 5 minSunscreen for Aging Concerns: The Most Evidence-Backed Step in SkincareIf one skincare claim has the strongest evidence behind it, it's daily sunscreen for aging-related skin concerns. Here is what the research actually shows.How Drop works · 5 minSunscreen Reapplication: Why Every 2 Hours Actually MattersSunscreen wears off faster than most people realize. What happens in those 2 hours, when reapplication matters most, and how to do it over makeup.
Browse all 668 ingredients — grouped by what they do, each with whatever evidence we can cite.
This page is public so a shared ingredient card always has its sources behind it — and so you can check them without an account.
Want more like this?
Every evidence-based flag cites its source, Drop tells you when your routine is complete, and it helps you simplify — instead of selling you more. The app launches on iOS and Android in October 2026. Rate my routine works today at /rate — no sign-in.