I get asked about our sunscreen formula more than almost any other product we make. People want to know why we use both zinc oxide and titanium dioxide instead of just one, what the percentages mean, and whether mineral sunscreen is actually better than the chemical stuff or just more expensive.
Fair questions. Here is what I have learned from formulating, testing, and wearing these products every day.
We make two mineral sunscreens and a tallow-based zinc oxide moisturizer. This guide covers what each ingredient actually does, where the claims fall apart, and where our own products fit. We have a commercial interest in mineral sunscreen performing well, which is exactly why we are transparent about where it does not.
- Zinc oxide is the only single ingredient that blocks both UVA and UVB. Titanium dioxide handles UVB and short-wave UVA but misses the deep UVA that causes photoaging.
- Together they cover the full UV spectrum at lower concentrations, which means less white cast and a formula you will actually want to wear.
- Non-nano particles (larger than 100nm) stay on the skin surface. Nano particles (smaller than 100nm) blend better but raise absorption questions for damaged skin.
- Mineral sunscreens work the second you put them on. Chemical sunscreens need 15 to 30 minutes to absorb before they do anything.
- The FDA classifies zinc oxide and titanium dioxide as the only two GRASE (Generally Recognized as Safe and Effective) sunscreen ingredients. Everything else is still under review.
Zinc Oxide vs Titanium Dioxide: How They Protect Skin Differently
| Property | Zinc Oxide | Titanium Dioxide |
|---|---|---|
| UVB protection (290-320nm) | Good | Excellent |
| UVA-II protection (320-340nm) | Good | Good |
| UVA-I protection (340-400nm) | Excellent | Poor |
| White cast | More noticeable | Less noticeable |
| Photostability | Stable | Stable |
| Comedogenic risk | Very low | Very low |
| Reef safety | Non-nano is reef-safe | Non-nano is reef-safe |
Both are mineral UV filters. They sit on the surface and physically bounce UV radiation away from your skin. But they cover different parts of the spectrum, and that gap is the whole reason formulas combine them.
UV attenuation properties of these two particles are complementary: titanium dioxide is primarily a UVB-absorbing compound, while zinc oxide is more efficient at UVA absorption. This is the foundational finding from the 2011 Smijs review in Nanotechnology, Science and Applications, which has been cited by 1,400+ subsequent studies and is the reason dermatologists recommend combination formulas.
The important row in the table above is UVA-I. That is the range responsible for photoaging, deep skin damage, and melanoma risk. It goes through clouds, through car windows, and deeper into your skin than UVB. Titanium dioxide barely touches it. Zinc oxide handles it well. But using both means you can run lower zinc oxide concentrations while keeping strong UVB coverage from the titanium dioxide. Lower concentrations means less of the chalky white layer that makes people give up on mineral sunscreen entirely.
Nano vs Non-Nano: What the Particle Size Actually Means
This is where sunscreen marketing gets genuinely confusing. Here is what the research actually says.
Non-nano particles are larger than 100 nanometers. They sit on the skin surface, do not get past the outer dead cell layer (the stratum corneum), and reflect UV mechanically. The downside: they leave a visible white cast because the particles are large enough to scatter visible light. That is physics, not a formulation failure.
Nano particles are smaller than 100nm. They blend more transparently because they scatter less visible light. The question everyone asks: do they get into living tissue? Based on the peer-reviewed dermal absorption studies I have read, intact skin does not allow meaningful nano-particle penetration. Broken skin, eczema, fresh wounds, post-procedure skin? That is a different situation. This is why most dermatologists recommend non-nano for anyone with a compromised skin barrier.
Bottom line: if safety is your priority and you can live with some white cast, go non-nano. If you need something that disappears on your skin and your barrier is intact, nano formulations from reputable brands are considered safe by the current evidence.
Why Mineral Sunscreen Instead of Chemical
Chemical sunscreens absorb UV and convert it to heat. Mineral sunscreens reflect it away. The practical differences that actually matter:
- Instant protection. Minerals work the moment they touch your skin. Chemical filters need 15 to 30 minutes to absorb and activate. If you put on sunscreen and walk out the door, mineral is already protecting you.
- No hormone disruption. Oxybenzone, octinoxate, and homosalate have documented endocrine disruption at certain exposure levels. Zinc oxide and titanium dioxide have none. This matters especially for pregnant women, children, and people with hormone-sensitive conditions.
- Better for reactive skin. Chemical filters are the most common cause of sunscreen-related contact dermatitis. If your face burns, stings, or breaks out from sunscreen, switching to mineral usually solves it.
- Better for acne-prone skin. Zinc oxide has documented anti-inflammatory and mildly antibacterial properties — it calms active breakouts rather than aggravating them. Chemical filters and heavy occlusive oils often make acne worse; properly formulated non-comedogenic mineral sunscreens usually do not.
- Reef safe (non-nano). Hawaii and Key West banned oxybenzone and octinoxate because of coral reef damage. Non-nano zinc oxide and titanium dioxide are not implicated.
- They do not break down in sunlight. Many chemical filters lose effectiveness after a few hours of UV exposure. Minerals are photostable. They work until you physically remove them.
The honest tradeoffs: mineral sunscreens can feel thicker. They leave more visible residue, especially on dark skin tones. They cost more. A $10 chemical sunscreen from the drugstore that you actually use every day protects your skin better than a $75 mineral sunscreen sitting in your cabinet. I would rather you wore something than nothing.
Avoid Aerosol Mineral Sunscreens
Spray-on mineral sunscreens are convenient and increasingly common, but the form factor introduces a respiratory concern that the industry rarely discusses openly. The Environmental Working Group flags inhalation risk for both zinc oxide and titanium dioxide aerosols because inhaled mineral particles are difficult for the lungs to clear.
The FDA has not finalized a safety position on aerosol mineral sunscreens, and there is no long-term human safety data for repeated inhalation. Use creams, lotions, or sticks instead. If you insist on a spray, hold your breath during application and avoid using near children's faces.
Tinted vs Non-Tinted: More Than Just Color
Tinted mineral sunscreens add iron oxides to the formula. This does two things that clear sunscreens cannot do, and most brands only talk about the first one.
The obvious benefit: iron oxides eliminate white cast. The tint neutralizes that chalky look, especially on medium and dark skin tones. A well-done universal tint works for most people without looking like foundation.
The benefit most brands skip explaining: iron oxides block visible light in the 400 to 450nm range. This is high-energy visible light, also called blue light. Neither zinc oxide nor titanium dioxide touches this range. And blue light from screens and indoor lighting contributes to hyperpigmentation, particularly in darker skin tones (Fitzpatrick types III through VI).
If you deal with melasma, post-inflammatory hyperpigmentation, or dark spots that seem to get worse despite wearing sunscreen religiously, this might be why. Your clear mineral sunscreen is stopping UV but letting visible light through. A tinted formula closes that gap.
What Percentages Should You Look For
| Use Case | Zinc Oxide | Titanium Dioxide | Expected SPF |
|---|---|---|---|
| Daily incidental exposure | 8 to 12% | 4 to 6% | SPF 30 to 40 |
| Extended outdoor activity | 15 to 20% | 5 to 8% | SPF 40 to 50+ |
| Post-procedure / compromised skin | 15 to 25% (non-nano) | Optional | SPF 30+ |
| Reef-safe beach use | 15 to 22% (non-nano) | 5 to 8% (non-nano) | SPF 30 to 50 |
The FDA allows up to 25% for both zinc oxide and titanium dioxide. Higher percentages mean more protection but also more white cast and heavier texture. There is a sweet spot for every use case.
Our PhysicalGuard Tinted Sunscreen sits at zinc oxide 10% and titanium dioxide 5.5%. We tested three other ratio combinations before landing on 10/5.5 — higher zinc gave better UVA coverage but unacceptable white cast, and lower titanium dropped the UVB numbers below where we wanted them. The 10/5.5 split delivered broad-spectrum coverage at SPF 38 in third-party testing with a tint most skin tones could wear daily. We added iron oxides for the blue light protection mentioned above, plus hyaluronic acid because mineral sunscreen should not be drying your skin out while protecting it.
Beyond UV: What Nobody Tells You About Infrared
This is the part of sun damage that the entire sunscreen industry mostly ignores.
Infrared radiation (IR-A, 700 to 1400nm) makes up roughly half of the solar energy hitting your skin. It goes deeper than UV, all the way to the hypodermis, and generates free radicals that break down collagen. This is photoaging that happens even when your SPF is doing its job perfectly against UV.
Neither zinc oxide nor titanium dioxide blocks infrared. No sunscreen mineral does. But a few botanical ingredients show activity against IR-A damage at the cellular level. Knotweed extract (Polygonum aviculare) is one we have studied and use. It reduces IR-induced free radical production in the mitochondria.
We include knotweed extract in our PhysicalGuard Non-Tinted formula for exactly this reason. It also contains niacinamide (vitamin B3) for skin clarity, so the formula is working on multiple fronts beyond basic UV blocking.
Is this essential? No. But if you are serious about anti-aging and already doing the UV protection part right, infrared is the next frontier worth knowing about.
When Mineral Sunscreen Is the Wrong Call
We make and sell mineral sunscreen, so it would be easy to pretend it is always the best choice. It is not. Here is when something else makes more sense:
- Heavy sweating or water sports. Minerals sit on the skin. They wash off faster than chemical filters that bond to the skin. If you are swimming laps, running in the heat, or surfing, a water-resistant chemical or hybrid formula will hold up better than minerals will.
- Very dark skin tones who do not like tinted products. Even good tinted mineral sunscreens can leave an ashy or grayish tone on the deepest skin (Fitzpatrick V-VI). Some people in this range are genuinely better served by chemical-only formulas for cosmetic comfort. I would rather someone wear chemical sunscreen daily than avoid mineral because of the appearance.
- Budget is tight. Quality mineral sunscreens cost more. Period. A $10 chemical SPF 50 that you wear every day beats a $75 mineral you skip. The best sunscreen is the one that actually ends up on your face.
- Full body beach days. The cost and texture of mineral sunscreen make it impractical for slathering head to toe. Use mineral on your face. Use whatever you will reapply generously on everything else.
Why Sunscreen Matters More After Shaving
Shaving is a form of mechanical exfoliation. Every pass of the razor removes dead skin cells along with hair, leaving fresher, thinner skin exposed. This newly revealed skin is more vulnerable to UV damage for several reasons:
- The protective outer layer has been partially removed
- Micro-abrasions from the blade create entry points for irritants
- Post-shave inflammation increases photosensitivity
Applying a mineral sunscreen after shaving provides a protective barrier that chemical sunscreens cannot match — no waiting period, no absorption into freshly compromised skin, and no stinging from chemical filters contacting micro-cuts.
For a complete post-shave routine, consider layering an Ectoin Face Serum under your sunscreen. Ectoin helps stabilize skin cells and reduce inflammation, making it an ideal partner for mineral sun protection on freshly shaved skin. This applies to women who shave their face as well — our women's face shaving guide covers the full routine.
How to Apply Mineral Sunscreen So It Actually Works
Application matters more with mineral sunscreen than chemical because you are building a physical shield, not soaking in a chemical. If the layer is uneven, the protection is uneven.
- Start with clean, dry skin after moisturizer. Give your moisturizer 2 to 3 minutes to absorb first. Applying sunscreen on top of wet skin dilutes the mineral layer.
- Use more than you think. For face and neck, a nickel-sized amount. Most people under-apply by about half, which drops an SPF 50 to roughly SPF 25 in practice. That is a huge real-world gap.
- Press it on, do not rub. Rubbing pushes minerals into pores and thins the layer in spots. Pressing and patting gives you more consistent coverage.
- Reapply every 2 hours in direct sun. Minerals do not break down, but they physically wear off from touching your face, sweating, and oil production.
- Goes under makeup. Mineral sunscreen sits under foundation. Tinted formulas can replace foundation entirely on light-coverage days.
How Our Sunscreens Compare to Other Mineral Brands
A few quick notes on how we sit relative to the popular mineral sunscreens people usually cross-shop:
- EltaMD UV Clear is the dermatologist favorite for acne-prone skin. It uses 9% zinc oxide only, no titanium dioxide, which means weaker UVB coverage on paper. Our tinted formula adds titanium dioxide to strengthen UVB at lower total mineral load.
- Blue Lizard Sensitive uses 10% zinc oxide and 5% titanium dioxide — nearly identical to our ratio. The difference is their formula includes fragrance-grade ingredients; ours is fully fragrance-free.
- Colorescience Sunforgettable is a loose mineral powder. Convenient for reapplication over makeup, but the delivery form means significantly less coverage per application than a cream. Good supplement, poor primary sunscreen.
- Supergoop Mineral Matte tints for medium skin tones only. Leaves a noticeable cast on Fitzpatrick V-VI. Our universal tint was formulated to reduce that gap.
None of these are bad products. Your skin tone, acne profile, and willingness to wear tint should drive the choice more than brand loyalty.
Our Mineral Sunscreens
We make two formulas. Both dermatologist approved, fragrance-free, paraben-free, and essential oil-free.
PhysicalGuard Tinted uses zinc oxide 10% plus titanium dioxide 5.5%. Universal tint with iron oxides for visible light and blue light protection. Hyaluronic acid for hydration. Water-resistant. Best for daily face use when you want even skin tone without separate foundation. $75.99.
PhysicalGuard Non-Tinted uses zinc oxide 12% plus titanium dioxide 7.5%. Knotweed extract for infrared protection. Niacinamide for skin clarity. Best for people who wear foundation over sunscreen or prefer a fully clear finish. $75.99.
For everyday moisturizing with incidental UV protection (not SPF-rated), our Grass-Fed Tallow Zinc Oxide Cream uses non-nano zinc oxide in a six-ingredient formula with no water, no preservatives, and no synthetics. It is a tallow moisturizer first, barrier cream second. $29.99.
Frequently Asked Questions
Is titanium dioxide and zinc oxide good for sunscreen?
Yes. They are the only two sunscreen ingredients the FDA classifies as GRASE (Generally Recognized as Safe and Effective). Zinc oxide covers UVA and UVB. Titanium dioxide strengthens UVB protection. Together they provide broader spectrum coverage than either alone, at lower concentrations, which means less white cast and better wearability.
What kind of sunscreen should I use if I have rosacea?
Mineral sunscreen with zinc oxide. Zinc oxide is anti-inflammatory and sits on the skin surface without causing the heat reaction that chemical sunscreens trigger in rosacea-prone skin. Skip fragranced formulas and chemical filters like oxybenzone, which are common rosacea irritants. A tinted mineral formula helps mask redness while protecting.
Is mineral sunscreen safe during pregnancy?
Mineral sunscreens are considered the safest option during pregnancy. Zinc oxide and titanium dioxide are not absorbed into the bloodstream. Chemical filters like oxybenzone and homosalate have been detected in blood plasma and breast milk. Most OB-GYNs and dermatologists recommend mineral-only sunscreen during pregnancy and breastfeeding.
What is the best sunscreen for melasma?
Tinted mineral sunscreen. Melasma is triggered by UV and visible light (blue light). Clear sunscreens, mineral or chemical, do not block visible light. The iron oxides in tinted formulas provide the visible light protection melasma requires. Wear it daily even indoors, since screen blue light can worsen melasma in susceptible people.
Does zinc oxide sunscreen leave a white cast?
Non-nano zinc oxide does leave a white cast, especially above 15% concentration. Nano zinc oxide (under 100nm) blends more transparently. Tinted formulas solve the problem entirely by adding iron oxides that neutralize the chalky look. The white cast is cosmetic only. Non-nano protects exactly the same regardless of appearance.
Last updated: April 2026. Added PMC citation, aerosol safety section, competitor comparison, and acne-prone skin detail.
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