You made the switch to mineral sunscreen. Good move. Zinc oxide and titanium dioxide are the only two active sunscreen ingredients the FDA has classified as safe and effective (GRASE) — and mineral formulas are generally better for sensitive skin, safer for kids, and gentler on the environment than their chemical counterparts.

But here’s something worth knowing: not all mineral sunscreens are as clean as they look on the front of the bottle. A few things have quietly crept into even the most wellness-forward formulas, and they’re easy to miss if you don’t know what to look for.

One of the most surprising things we've found in the sunscreen space? Many products marketed as "clean" actually contain microplastics. Ingredients like dimethicone, nylon-12, and acrylates copolymer are classified as microplastics by the European Chemicals Agency — and they show up regularly in SPF formulas, even ones with "clean" or "natural" on the front of the bottle. They're added intentionally for texture and feel, which makes them easy to overlook. Research from the Beat the Microbead campaign found that over 72% of sunscreens tested contain at least one microplastic ingredient. It's one of the reasons we think reading the full ingredient list — not just the marketing language — matters so much.

Here’s your practical guide to reading a sunscreen label — and knowing exactly what you’re getting.

Step 1: Check the Active Ingredients

This one is straightforward. Flip the bottle and find the Drug Facts box. Under “Active Ingredients,” you should see one or both of these:

• Zinc oxide
• Titanium dioxide

That’s it. If you see anything else listed as an active — oxybenzone, avobenzone, homosalate, octisalate, octocrylene, octinoxate — you’re looking at a chemical sunscreen or a hybrid, not a true mineral formula. These chemical filters remain under FDA review with insufficient data to confirm they’re safe for regular use, which is exactly why so many people moved to mineral in the first place.

Step 2: Look for “Non-Nano” on the Label

Here’s something most brands don’t advertise clearly: zinc oxide and titanium dioxide can be processed into particles so small they’re classified as nanoparticles — tiny enough that they may penetrate the skin barrier rather than sitting on top of it the way a mineral filter is supposed to work. Research also suggests nanoparticles may be toxic to coral larvae and marine life. (EWG Sunscreen Guide)

The good news is there’s an easy fix: look for the word “non-nano” somewhere on the label or product page. Non-nano particles are large enough to stay on the surface of your skin and do their job as a physical barrier.

A quick rule of thumb from the Save the Reef Foundation: if the formula doesn’t say “non-nano” or “micro-sized” and it rubs in completely clear, the particles are probably nano-sized.

Step 3: Scan the Inactive Ingredients for Hidden Chemical Filters

This is the one that surprises people most — even people who work in the beauty industry.

Making a mineral sunscreen that feels elegant and lightweight is genuinely hard. High concentrations of zinc oxide (to get a high SPF rating) can feel thick and leave a white cast. To get around this, many brands add ingredients to the inactive side of the label that are chemically modified versions of traditional UV filters. They absorb UV light the same way, but because they’ve been structurally tweaked, they don’t have to be listed as active sunscreen ingredients. They quietly boost the SPF number while the front of the bottle still says “100% mineral.”

The industry has a name for this: “sunscreen doping.” 

According to BeautyMatter, these boosters can inflate SPF ratings by 10–30 points, and they allow brands to use far less actual zinc oxide — which can reduce real UVA protection even as the SPF number climbs.

As cosmetic chemist Dr. Michelle Wong explains, these ingredients “aren’t technically sunscreen actives, so they’re not in the Drug Facts panel.”

What to look for in the inactive ingredients list:

• Butyloctyl salicylate — the most common SPF booster, structurally similar to octisalate
• Tridecyl salicylate — same family
• Ethylhexyl methoxycrylene — structurally similar to octocrylene
• Polyester-8 — another common booster

If you see any of these in a formula claiming to be 100% mineral, the product is functioning more like a hybrid than a true mineral sunscreen. If you are trying to avoid chemical active ingredients, you will want to also avoid these.

Step 4: Check for Microplastics

The word “clean” isn’t regulated — any brand can use it — and that’s led to a real blind spot in the sunscreen category. Many sunscreens marketed as “clean” contain ingredients classified as microplastics by the European Chemicals Agency. Research from the Beat the Microbead campaign found that over 72% of sunscreens tested contain at least one microplastic ingredient.

These are added intentionally — they create the silky, blurring textures that make a sunscreen enjoyable to wear. But they don’t biodegrade. They wash off in the shower and the ocean and accumulate in waterways and marine life over time.

Microplastic ingredients to watch for:

• Dimethicone and other silicones (cyclopentasiloxane, cyclohexasiloxane)
• Nylon-12 or nylon-6
• Acrylates copolymer
• Polyethylene
• Any ingredient ending in -siloxane or -cone

Step 5: Know What “Reef Safe” Actually Means

If you’re seeing “reef safe” on a sunscreen and taking it as a seal of approval, it’s worth knowing that the term is completely unregulated. There is no FDA definition, no required certification, and no regulatory body reviewing products before that phrase goes on the label. NOAA confirms there is currently no standard for what it means.

Some brands earn the label simply by removing oxybenzone and octinoxate — the two chemical filters banned in Hawaii. But research has linked a broader list of filters to marine ecosystem harm, including octocrylene, homosalate, and avobenzone. The FTC took action against one major sunscreen brand in 2023, resulting in a $300,000 settlement over “reef safe” and “ocean friendly” claims on products that still contained chemical filters linked to marine harm.

In early 2026, California introduced AB 1744, a bill that would make it illegal to use “reef safe” or “ocean safe” language on sunscreen labels unless a product meets specific ingredient requirements. That kind of legislation doesn’t happen unless there’s been a real problem.

What genuinely reef-friendlier sunscreen looks like: non-nano zinc oxide as the active ingredient, none of the chemical filters or SPF boosters listed above, no microplastics, no parabens or triclosan. Check the full ingredient list — not just the front label.

Your Quick Reference Checklist

Before you buy, run through this:

1. Active ingredients are zinc oxide and/or titanium dioxide only ✅
2. Label says “non-nano” (or “micro-sized”) ✅
3. No SPF boosters in the inactives: no butyloctyl salicylate, tridecyl salicylate, ethylhexyl methoxycrylene, or polyester-8 ✅
4. No microplastics: no dimethicone, nylon-12, acrylates copolymer, or -siloxane ingredients ✅
5. No parabens or triclosan ✅
6. No oxybenzone, octinoxate, octocrylene, homosalate, or PABA ✅

If you’re looking for a mineral sunscreen that checks every one of those boxes, we built ours to do exactly that. Our Hydrating Mineral Face Sunscreen SPF 50, Mineral Body Sunscreen SPF 50, and Invisible Matte Ceramide Sunscreen Serum SPF 30 use non-nano zinc oxide as the only active ingredient — nothing hidden, nothing extra. Read the label. We want you to.

Sources:

FDA on Sunscreen Ingredients  ·  EWG Sunscreen Guide  ·  NOAA on Reef Safe Sunscreen  ·  FTC Settlement

European Chemicals Agency on Microplastics  ·  Beat the Microbead  ·  BeautyMatter on SPF Boosters

Lab Muffin Beauty Science  ·  Save the Reef Foundation  ·  California AB 1744