What's inside
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Zinc Oxide 15.98%
Cosmetic ColorantWater
Skin ConditioningCaprylic/Capric Triglyceride
MaskingPropanediol
SolventC12-15 Alkyl Benzoate
AntimicrobialPolyglyceryl-6 Stearate
EmollientGlycerin
HumectantNiacinamide
SmoothingPolyhydroxystearic Acid
EmulsifyingArachidyl Alcohol
EmollientSqualane
EmollientBis-Diglyceryl Polyacyladipate-2
EmollientPanthenol
Skin ConditioningGlyceryl Glucoside
HumectantXylitylglucoside
HumectantBioflavonoids
Skin ConditioningBisabolol
AntioxidantXylitol
HumectantButylene Glycol
HumectantCeramide NP
Skin ConditioningHydroxyacetophenone
AntioxidantPortulaca Oleracea Extract
Skin ConditioningPalmitoyl Hexapeptide-12
Skin ConditioningBrassica Oleracea Italica Extract
AstringentCamellia Sinensis Leaf Extract
AntimicrobialHydrolyzed Hyaluronic Acid
HumectantSodium Hyaluronate
HumectantPinus Pinaster Bark Extract
AntioxidantArtemisia Annua Extract
MaskingCentella Asiatica Extract
CleansingAloe Barbadensis Leaf Extract
EmollientUbiquinone
AntioxidantArgania Spinosa Kernel Oil
EmollientAllantoin
Skin ConditioningTocopheryl Acetate
AntioxidantAnhydroxylitol
HumectantArachidyl Glucoside
EmulsifyingAstaxanthin
Skin ConditioningTocopherol
AntioxidantCetearyl Alcohol
EmollientLecithin
EmollientIsostearic Acid
CleansingCoco-Glucoside
CleansingBehenyl Alcohol
EmollientPolyglyceryl-6 Behenate
Emulsion StabilisingPolyglyceryl-3 Polyricinoleate
EmulsifyingXanthan Gum
EmulsifyingEthylhexylglycerin
Skin ConditioningSorbitan Isostearate
EmulsifyingPentaerythrityl Tetraisostearate
EmollientHydrogenated Lecithin
EmulsifyingPectin
Emulsion Stabilising1,2-Hexanediol
Skin ConditioningCaprylhydroxamic Acid
Sodium Citrate
BufferingPolyacrylate Crosspolymer-6
Emulsion StabilisingHydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
Emulsion StabilisingStearalkonium Hectorite
Gel FormingHaematococcus Pluvialis Oil
AntioxidantPropylene Carbonate
SolventCarrageenan
CI 77492
Cosmetic ColorantCI 77491
Cosmetic ColorantCI 77499
Cosmetic ColorantZinc Oxide 15.98%, Water, Caprylic/Capric Triglyceride, Propanediol, C12-15 Alkyl Benzoate, Polyglyceryl-6 Stearate, Glycerin, Niacinamide, Polyhydroxystearic Acid, Arachidyl Alcohol, Squalane, Bis-Diglyceryl Polyacyladipate-2, Panthenol, Glyceryl Glucoside, Xylitylglucoside, Bioflavonoids, Bisabolol, Xylitol, Butylene Glycol, Ceramide NP, Hydroxyacetophenone, Portulaca Oleracea Extract, Palmitoyl Hexapeptide-12, Brassica Oleracea Italica Extract, Camellia Sinensis Leaf Extract, Hydrolyzed Hyaluronic Acid, Sodium Hyaluronate, Pinus Pinaster Bark Extract, Artemisia Annua Extract, Centella Asiatica Extract, Aloe Barbadensis Leaf Extract, Ubiquinone, Argania Spinosa Kernel Oil, Allantoin, Tocopheryl Acetate, Anhydroxylitol, Arachidyl Glucoside, Astaxanthin, Tocopherol, Cetearyl Alcohol, Lecithin, Isostearic Acid, Coco-Glucoside, Behenyl Alcohol, Polyglyceryl-6 Behenate, Polyglyceryl-3 Polyricinoleate, Xanthan Gum, Ethylhexylglycerin, Sorbitan Isostearate, Pentaerythrityl Tetraisostearate, Hydrogenated Lecithin, Pectin, 1,2-Hexanediol, Caprylhydroxamic Acid, Sodium Citrate, Polyacrylate Crosspolymer-6, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Stearalkonium Hectorite, Haematococcus Pluvialis Oil, Propylene Carbonate, Carrageenan, CI 77492, CI 77491, CI 77499
Zinc Oxide 16.75%
Cosmetic ColorantWater
Skin ConditioningCaprylic/Capric Triglyceride
MaskingC12-15 Alkyl Benzoate
AntimicrobialSqualane
EmollientPolyglyceryl-2 Dipolyhydroxystearate
Skin ConditioningPropanediol
SolventShea Butter Ethyl Esters
EmollientGlycerin
HumectantC13-15 Alkane
SolventPolyglyceryl-3 Diisostearate
EmulsifyingDimethicone
EmollientPolyhydroxystearic Acid
EmulsifyingPolyglyceryl-3 Polyricinoleate
EmulsifyingSodium Chloride
MaskingDisteardimonium Hectorite
StabilisingPhenoxyethanol
PreservativeTocopheryl Acetate
AntioxidantPolysilicone-11
Argania Spinosa Kernel Oil
EmollientButyrospermum Parkii Butter
Skin ConditioningAllantoin
Skin ConditioningEthylhexylglycerin
Skin ConditioningRicinus Communis Seed Oil
MaskingBisabolol
AntioxidantIsopropyl Titanium Triisostearate
EmollientSodium Hyaluronate
HumectantAnnona Muricata Fruit Extract
Skin ConditioningEuterpe Oleracea Fruit Extract
Hylocereus Undatus Fruit Extract
Skin ConditioningMangifera Indica Fruit Extract
Skin ConditioningPersea Gratissima Fruit Extract
EmollientPrunus Domestica Fruit Extract
MoisturisingPsidium Guajava Fruit Extract
AstringentTamarindus Indica Extract
SmoothingTocopherol
AntioxidantCI 77491
Cosmetic ColorantCI 77492
Cosmetic ColorantZinc Oxide 16.75%, Water, Caprylic/Capric Triglyceride, C12-15 Alkyl Benzoate, Squalane, Polyglyceryl-2 Dipolyhydroxystearate, Propanediol, Shea Butter Ethyl Esters, Glycerin, C13-15 Alkane, Polyglyceryl-3 Diisostearate, Dimethicone, Polyhydroxystearic Acid, Polyglyceryl-3 Polyricinoleate, Sodium Chloride, Disteardimonium Hectorite, Phenoxyethanol, Tocopheryl Acetate, Polysilicone-11, Argania Spinosa Kernel Oil, Butyrospermum Parkii Butter, Allantoin, Ethylhexylglycerin, Ricinus Communis Seed Oil, Bisabolol, Isopropyl Titanium Triisostearate, Sodium Hyaluronate, Annona Muricata Fruit Extract, Euterpe Oleracea Fruit Extract, Hylocereus Undatus Fruit Extract, Mangifera Indica Fruit Extract, Persea Gratissima Fruit Extract, Prunus Domestica Fruit Extract, Psidium Guajava Fruit Extract, Tamarindus Indica Extract, Tocopherol, CI 77491, CI 77492
Reviews
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
Allantoin is a soothing ingredient known for its protective and moisturizing properties; it's basically a quiet workhorse ingredient you can find in a huge range of cosmetics.
Though it can be derived from the comfrey plant, allantoin is produced synthetically for cosmetic products to ensure purity.
Research shows it can encourage your skin cells to turn over and renew by stimulating keratinocyte and fibroblast proliferation.
It also has mild keratolytic properties to help loosen and shed dead skin cells without being harsh.
Studies also suggest allantoin can help calm inflammation by dialing down some of the chemical signals your skin sends out when it is irritated.
This ingredient is typically used in the 0.1-0.5% range, and the FDA recognizes it as a skin protectant in OTC products up to 2%.
Overall, allantoin is a wonderful addition to most routines; it is stable across a wide pH range (~4-8), works well with other ingredients, and is considered non-sensitizing/non-irritating.
Fun fact: Allantoin is naturally occurring in comfrey root, beets, chamomile, and wheat sprouts. Our bodies even produce it as a byproduct of uric acid metabolism.
Learn more about AllantoinYou may know this ingredient as argan oil. It has emollient and skin conditioning properties that help soften skin and reinforce the lipid barrier.
The fatty acid profile of argan oil is roughly 45-55% oleic acid, 28-36% linoleic acid, 10-15% palmitic acid, and 5-7% stearic acid. It also contains vitamin E, sterols, squalene, and polyphenols like ferulic acid.
Two clinical studies in postmenopausal women found that applying argan oil for 60 days significantly improved skin elasticity and moisturization (reduced transepidermal water loss and increased epidermal water content).
Since it is high in oleic and linoleic acid, this ingredient may not be fungal acne safe. Both of these fall in the C11-C24 range that Malassezia yeast can metabolize.
Learn more about Argania Spinosa Kernel OilBisabolol is a gentle skin conditioner, antioxidant, and soothing ingredient.
It's primary claim to fame is soothing and research shows topically applied bisabolol can quiet the chemical messengers that cause your skin to become inflamed, helping to sooth any irritation.
A clinical study found that applying 0.5% bisabolol daily for 8 weeks produced an average 9% decrease in skin pigmentation. Researchers found it can also suppress the process that leads to excess melanin production in skin.
In vitro studies found that bisabolol combined with propylene glycol significantly increased skin permeability by increasing lipid fluidity in the stratum corneum.
You'll likely see use concentrations quite low, usually 0.1-0.2%.
Overall, this is a well-tolerated ingredient that works well in formulas designed for sensitive, reactive, or post-procedure skin.
Learn more about BisabololC12-15 Alkyl Benzoate is a lightweight emollient made by combinig benzoic acid with fatty alcohols that are 12-15 carbons long.
In cosmetics, it plays several roles:
The Cosmetic Review Expert Panel has concluded the alkyl benzoate group to be safe as used in cosmetics; it wasn't found to be a skin irritant and unlikely to be absorbed due to its low water solubility.
This report recorded almost 1000 reported uses with concentrations up to 59% in leave-on products but your cosmetics will typically use 0.5-15% depending on the product.
It's often called a "SPF booster": this is because it keeps UV filters properly dissolved and evenly distributed to support a sunscreen's performance. It doesn't actually raise SPF on its own.
Overall, this ingredient is well tolerated.
This ingredient is fungal acne safe because it is an ester of benzoic acid.
Think of this ingredient as two parts stuck together: an oily part and an acid part. Malassezia only gets a meal when it can snip off a fatty acid to eat. With C12-15 Alkyl Benzoate, the acid part is benzoic acid, which isn't a fatty acid and which the yeast can't use as food.
Benzoic acid is actually used as a preservative to stop yeast from growing.
The oily part is a blend of C12-15 fatty alcohols but fatty alcohols in this size range can support only a little Malassezia growth (mostly for one species of Malassezia as well).
In the ingredient, those alcohols stay locked inside the molecule. The yeast can only reach them by snipping the benzoate bond, and that type of bond is harder for it to cut than a normal fatty bond.
So not much gets released. And whatever does get snipped comes packaged with benzoic acid, which discourages yeast growth.
Learn more about C12-15 Alkyl BenzoateCaprylic/Capric Triglyceride (aka MCT Oil) is a lightweight emollient, solvent, and texture enhancer. It is considered a skin-softener by helping to prevent moisture loss.
Though it behaves like an oil, it is not technically one due to its chemical composition. One perk of this ingredient is that it is very stable, resistant to oxidation, and unlikely to go rancid.
In practice, that translates to a long shelf life and a consistently elegant skin feel.
While there is an assumption Caprylic Triglyceride can clog pores due to it being derived from coconut oil, there is no research supporting this. Just patch test if you have concerns.
Fractionated coconut oil and MCT Oil are both listed as Caprylic/Capric Triglyceride according to INCI. This is because INCI names are based on the ingredient’s final chemical composition and not its marketing name or source.
This ingredient is treated as the gold standard fungal acne safe oil. Even though it is coconut derived, the problematic lauric acid is stripped out.
This leaves just caprylic (C8) and capric (C10) acid. These chain lengths actually trend antifungal; a 2020 study found caprylic acid was enough to disrupt Malassezia furfur cell membrane, with a caprylic acid derivative damaging membrane structures at concentrations as low as 0.2%.
Learn more about Caprylic/Capric TriglycerideCi 77491 is also hydrated iron III oxide. It's sole purpose is to give a red/pink hue to products.
Iron III oxides are classified as inorganic chemicals for coloring.
Synthetically created Ci 77491 is considered safer than those naturally found. This is because the synthetically created version may contain less impurities. Iron oxides are generally non-toxic and non-allergenic.
Learn more about CI 77491CI 77492 is also hydrated iron III oxide. It's sole purpose is to give a yellow hue to products.
Iron III oxides are classified as inorganic chemicals for coloring.
Synthetically created CI 77492 is considered safer than those naturally found. This is because the synthetically created version may contain less impurities. Iron oxides are generally non-toxic and non-allergenic.
Learn more about CI 77492Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.
Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.
Learn more about EthylhexylglycerinGlycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
Topically, glycerin does several things at once:
Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.
Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.
This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.
Just know very high concentrations (>40%) can feel tacky in low humidity.
Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
Learn more about GlycerinPolyglyceryl-3 Polyricinoleate is a plant-derived emulsifier made by combining glycerin and ricinoleic acid.
It works well for giving buttery lip balms and low-viscosity water-in-oil emulsions a non-greasy and pleasant skin feel.
Typical concentrations range from 0.1-3%.
This ingredient is mild and non-irritating in nature.
Because it is derived from ricinoleic acid, this ingredient may not be fungal acne safe. Ricinoleic acid is an unsaturated fatty acid that the Malassezia yeast can metabolize.
Learn more about Polyglyceryl-3 PolyricinoleatePolyhydroxystearic Acid is a vegetable-derived soft wax made from castor oil. It's an emulsion stabilizer, thickener, and film former.
You'll likely see it in sunscreens because it helps disperse pigments and UV-reflecting minerals like titanium dioxide and zinc oxide evenly.
Depending on the concentration, it can drastically change the texture of a product from pasty solid (like lipstick) to sprayable liquid.
The CIR Expert Panel for Cosmetic Ingredient Safety has concluded this ingredient to be safe in cosmetics. The highest reported use concentration is 14.2% in lipsticks.
Learn more about Polyhydroxystearic AcidPropanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.
It’s often used to:
Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.
Learn more about PropanediolSodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.
In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.
Interestingly, the size of the molecule affects its behavior:
Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.
Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.
You'll typically see concentrations between 0.1-2% for this ingredient.
Learn more about Sodium HyaluronateSqualane is the hydrogenated and shelf-stable form of squalene (a lipid that naturally occurs in human sebum).
It is an emollient and skin conditioning agent that is able to integrate seamlessly into the skin's lipid barrier without clogging pores.
This is due to how structurally similar it is to what your skin already produces.
Though it is mostly an emollient that helps soften and hydrate skin, it also has some humectant and occlusive action. Humectants help the skin retain moisture while occlusives seal it in, making squalane a triple-threat moisturizer.
Research shows it has antioxidant capabilities that help protect against stressors like UV exposure, specifically UVA induced oxidative stress. This study also found that it supports collagen biosynthesis in human dermal fibroblasts.
No clinical study has reported significant adverse effects and irritation reactions are very rare from this ingredient (even at 100% concentration).
Overall, it's a fantastic ingredient for hydration and is suitable for all skin types.
This depends on the source. Squalane can be derived from both plants and animals. Most squalane used in skincare comes from plants.
Please note: the source of squalane is only known if disclosed by the brand. We recommend reaching out to the brand if you have any questions about their squalane.
Read more about squalene with an "e".
Though squalane is often called an oil, it’s technically not one. It is a hydrocarbon, meaning it is only made of carbon and hydrogen. True oils are triglycerides and made of fatty acids and glycerol.
The term “oil-free” isn’t regulated so companies can define it however they want. Some exclude all oils, while others just avoid mineral oil or comedogenic oils.
Squalane has a comedogenic rating of 1 from the original 1972 study that tested raw ingredients under occlusion on rabbit ears. This system is not standardized or peer-reviewed, and using the raw ingredients is very different from how diluted cosmetic formulations are used on human skin.
A comedogenic rating of 1 means it is "unlikely to clog pores" according to the original rating system.
The overall formula of a product matters more than the individual ingredients on whether or not it will cause clogged pores.
Learn more about SqualaneTocopherol is a fat-soluble antioxidant known as Vitamin E.
You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.
Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.
It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.
This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.
This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.
In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.
Concentrations usually range from 0.1-1% in most leave-on products.
Learn more about TocopherolTocopheryl Acetate is a stable, shelf-friendly form of vitamin E.
Formulators love it because plain vitamin E oxidizes quickly once it hits air. This acetate version stays stable and resists going off, helping to extend a product's shelf life.
It's actually inactive on its own and works like a slow-release "storage" form; the enzymes in your skin called esterases gradually convert it into active vitamin E over time.
One in vivo study showed 5% of the acetate in the living layer of the epidermis converted to vitamin E after 5 days of application. This study also found the skin gained protection against UV damage even though the conversion was slow and small.
Once converted, vitamin E acts as a skin's main fat-soluble antioxidant that fights free radicals to protect skin from damage.
Topical vitamin E generally boosts the skin's photoprotection, and it reduced UV-damage in animal models.
This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.
Overall, it has a pretty solid safety profile and has been found to be non-irritating and non-comedogenic. Allergic reactions may happen but stay rare due to how widely the ingredient gets used.
The concentration will vary depending on the formula; industry data shows 0.1% in baby lotions, 3% in lipsticks, and 5% in foot powders. You can also find this ingredient at 100% in a pure vitamin E oil.
Most leave-on skincare keeps it at the lower end, often between 0.5-1%.
Learn more about Tocopheryl AcetateWater. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.
So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!
Learn more about WaterZinc Oxide (ZO) is a mineral broad-spectrum UV filter and the broadest-spectrum filter recognized by the FDA. It covers everything from UVB through to long-wave UVA.
On top of sun protection, it has skin protectant and skin-soothing properties too.
Here's a myth worth busting: mineral filters are usually described as working by "reflecting" or "bouncing" UV off your skin.
That's mostly not true: when researchers actually measured it, ZO and Titanium Dioxide reflect only about 4-5% of UV (less than SPF 2 worth of protection).
The vast majority of the work (~95%) is done by absorption, similar to chemical UV filters. ZO is a semiconductor that absorbs UV photos through its energy band gap.
So the old "physical blocker vs. chemical absorber" framing is really an oversimplification.
Zinc Oxide is one of the most effective broad-spectrum UV filters out there. It protects across UVB, UVA2, and UVA1 with a flat, even absorption curve across the whole UVA-UVB range.
That uniform UVA coverage is its standout feature; titanium dioxide skews more toward UVB as its particle size drops so ZO gives more consistent and extended UVA protection.
It's also very photostable. As an inorganic oxide, ZO doesn't break down in sunlight the way some organic filters can, so it holds up over a day of wear.
This ingredient is gentle and soothing, making it go-to for sunscreens aimed at sensitive skin, rosacea, or ecezma-prone skin, babies, and children.
It's also unlikely to cause the "eye sting" that some sunscreen ingredients are known for, and regulatory agencies broadly consider it non-toxic and safe for topical use.
Beyond sun protection, ZO is also a recognized OTC skin protectant. It forms a breathable barrier that shields skin from moisture and irritation while supporting healing. This is why you'll see it as a classic active in diaper rash creams.
The only downside to ZO is that it can leave a visible white cast, especially on deeper skin tones. This is the main reason mineral sunscreens have historically felt less cosmetically elegant than chemical or hybrid formulas.
Zinc Oxide comes in both non-nano and nano forms. The dividing line is 100nm and anything under is classified as a nanomaterial by the EU.
The nano version scatters less visible light which cuts down white case and gives a lighter, more wearable texture.
Another thing worth understanding about formulation:
Uncoated ZO has some inherent photocatalytic activity. This just means it can generate reactive oxygen species under UV. It's exactly why cosmetic-grade ZO is almost always surface-coated; this coating suppresses that reactivity and improves how the powder disperses and feels.
A well-formulated coated ZO largely sidesteps this issue.
Zinc Oxide is commonly used anywhere from 10% up to the regulatory maximum in sunscreens (25%).
Mineral-only broad-spectrum products often land in the 15-25% range to hit higher SPF and UVA values. Keep in mind SPF performance depends heavily on particle size, dispersion, and the rest of the formula, and not just the percentage.
As an OTC skin protectant like diaper creams, ZO typically runs higher at roughly 10-40%.
This ingredient is generally easy to work with and doesn't photodegrade.
The only thing to know is that uncoated ZO can be a bit reactive in a formula.
Under UV, it can break down sensitive ingredients like other actives or UV filters. This is another reason coated versions are standard. ZO can also react with very acidic ingredients or throw off stability of some creams. A good formula will get around this with the right coatings and dispersion.
The EU's Scientific Committee on Consumer Safety has concluded that ZO nanoparticles "can be considered to not pose any risk of adverse effects in humans after application on healthy, intact or sunburnt skin".
You might hear that ZO is "toxic"; this is because an in-vitro (test tube) study suggested micronized ZO had potential phototoxicity. In vivo (human) investigations have disputed this and the results have come back reassuring.
So does ZO penetrate skin? The short answer is no, not in any way that matters.
The most relevant evidence comes from real-world human studies: in one, volunteers applied ZO nanoparticle sunscreen hourly for six hours and daily for five days. The advanced imaging showed the particles stayed on the surface and never reached the living epidermis, and no cellular toxicity was found.
Other in-vivo and ex-vivo work agree; ZO nanoparticles don't cross the stratum corneum, even on flexed, massaged, or barrier-impaired skin.
A small amount of solubilized zinc ions can dissolve off the particles and enter the upper skin. But the quantities are tiny compared to the zinc already naturally present in your body, and studies haven't found this to cause local toxicity.
The sunscreen bans you've heard of (like Hawaii's) are aimed at two chemical filters, Oxybenzone and Octinoxate. ZO itself it not banned and is often recommended instead.
So far, there's no solid evidence that any form of ZO harms reefs. It is an ongoing and active area of study, and worth keeping an eye on.
If you're traveling somewhere with these rules, a non-nano mineral sunscreen is the safe bet.
Learn more about Zinc Oxide