Chemical vs. Mineral Sunscreen: How They Work and Which to Choose

Mineral sunscreen uses zinc oxide or titanium dioxide as its active ingredient. Chemical sunscreen uses organic UV filters such as avobenzone, homosalate, octisalate, and octocrylene. Both work, and both mostly absorb UV rather than bouncing it off. The differences that matter are how many filters a formula needs, how those filters hold up in sunlight, how the finished product feels, and how long the ingredient list gets. Swellies is a mineral sunscreen with one active: 21 percent non-nano zinc oxide, which covers UVA and UVB on its own.

Chemical vs. mineral sunscreen at a glance

How each one works

The old line is that mineral sunscreen reflects UV like a mirror and chemical sunscreen absorbs it. Half of that is out of date. Zinc oxide absorbs most of the UV that hits it and scatters a small portion. Chemical filters absorb UV and release the energy as a small amount of heat. So the useful question is not absorb versus reflect. It is what is doing the absorbing, and how well it holds up. The physics is in how zinc oxide blocks UV.

The bigger practical difference is coverage. Zinc oxide covers both UVB, the rays that burn, and UVA, the rays that drive aging and pigment, across the whole range from one ingredient. Each chemical filter covers a slice of the spectrum, so a chemical sunscreen usually combines three to five of them to reach broad spectrum. Here is what broad spectrum has to earn.

Stability, and why chemical formulas get long

Avobenzone is the most common UVA filter in chemical sunscreen, and on its own it breaks down in sunlight. Formulators pair it with other ingredients to keep it working. Those additions bring their own texture problems, which bring more ingredients to fix the texture. That chain is a big part of why a typical chemical sunscreen lists 20 to 30 ingredients.

Zinc oxide is photostable. It does not degrade in light, so there is nothing to stabilize and no second filter to add. That is how a mineral formula can get down to five ingredients. The longer case for short lists is in 5 ingredients vs. 30.

Where it sits on your skin

Chemical filters work by absorbing into the upper layers of skin. Non-nano zinc oxide works from the surface. The particles are large enough that they stay on top of your skin rather than going into it. For people who would rather keep their sunscreen on the outside, that is the reason they choose mineral. More on particle size in non-nano zinc oxide.

It also explains the sting. Chemical filters can migrate with sweat and water into your eyes. A mineral film that stays put on the surface does not travel the same way. More in sunscreen that doesn't burn your eyes.

How they feel

This is where chemical sunscreen earned its market share. Chemical filters are clear liquids, so they disappear on skin. High-load zinc oxide used to go on thick and white, and plenty of people tried mineral once and went back.

Formulation caught up. In Swellies, Polyhydroxystearic Acid keeps the zinc evenly dispersed so it does not clump into a white film, Iron Oxides add a sheer tint that cancels what is left, Dextrin Palmitate turns it into a breathable gel, and a lightweight ester called Coco Caprylate/Caprate carries it all without grease or silicone. The result is 21 percent zinc oxide that wears like a serum. More in mineral sunscreen for oily skin.

Reefs and rivers

Hawaii banned the sale of sunscreens containing oxybenzone and octinoxate starting in 2021, citing coral reefs, and other places have followed with their own restrictions. Mineral actives have not been part of those bans. "Reef safe" on a label is not a regulated term, though, so the full ingredient list is what counts. We broke that down in what reef-safe means.

How to tell which one you are holding

Turn the bottle over to the Drug Facts panel and read the Active Ingredients line. If the only actives are zinc oxide, titanium dioxide, or both, it is a mineral sunscreen. If you see anything else, it is chemical or a hybrid. Some products sold as mineral include a chemical filter alongside the zinc, so check every active, not just the first one. And "mineral" says nothing about the inactive list, where silicone often shows up. Here is where silicone hides.

Which should you choose?

The best sunscreen is the one you will wear every day. If you want a single active that covers UVA and UVB on its own, does not break down in the sun, stays on the surface of your skin, and comes with an ingredient list you can read in ten seconds, choose mineral.

Swellies is five ingredients: non-nano zinc oxide at 21 percent, Coco Caprylate/Caprate, Dextrin Palmitate, Polyhydroxystearic Acid, and Iron Oxides. Broad Spectrum SPF 46, water resistant 40 minutes, no white cast. No chemical filters, no fragrance, no silicones, no preservatives.

Frequently asked questions

What is the difference between chemical and mineral sunscreen?

Mineral sunscreen uses zinc oxide or titanium dioxide as the active ingredient. Chemical sunscreen uses organic UV filters such as avobenzone, homosalate, and octocrylene. Both absorb UV. Zinc oxide covers UVA and UVB on its own and is photostable, while chemical formulas usually combine several filters to reach broad spectrum coverage.

Is mineral sunscreen better than chemical sunscreen?

Both protect you when used as directed. Mineral sunscreen has practical advantages: zinc oxide covers the full UV range from one active, it does not break down in sunlight, non-nano zinc stays on the skin surface, and formulas can be far shorter. Mineral historically lost on white cast and texture, which modern formulation has largely solved.

Does mineral sunscreen reflect UV?

Mostly no. That is a common myth. Zinc oxide absorbs most of the UV that reaches it and scatters a smaller share. The difference from chemical sunscreen is not absorbing versus reflecting. It is that zinc oxide is a single, photostable mineral active that covers both UVA and UVB.

Why does chemical sunscreen sting my eyes?

Chemical filters can migrate with sweat and water, which carries them into the eyes. Mineral sunscreen works from a film on the surface of the skin that does not travel the same way.

Which is better for sensitive skin, mineral or chemical sunscreen?

Many people with reactive skin prefer mineral because zinc oxide sits on the surface of the skin and mineral formulas can be made with far fewer ingredients, which leaves fewer things to react to. Individual skin varies, so patch testing a new sunscreen on a small area first is sensible.

Is mineral sunscreen reef safe?

Mineral actives have not been included in the sunscreen bans passed in places like Hawaii, which target oxybenzone and octinoxate. "Reef safe" is not a regulated term in the United States, so check the full ingredient list rather than relying on a front-of-bottle claim.

How do I know if my sunscreen is mineral or chemical?

Read the Active Ingredients line in the Drug Facts panel. If the only actives listed are zinc oxide, titanium dioxide, or both, it is a mineral sunscreen. Any other active means it is chemical or a hybrid of the two.

One active, zinc oxide. Five ingredients total. Shop Swellies SPF 46 →