What's inside
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Skin ConditioningCyclopentasiloxane
EmollientButylene Glycol
HumectantHomosalate
Skin ConditioningCI 77891
Cosmetic ColorantGlycerin
HumectantCyclohexasiloxane
EmollientC12-15 Alkyl Benzoate
AntimicrobialCaprylyl Methicone
Skin ConditioningTrimethylsiloxysilicate
EmollientZinc Oxide
Cosmetic ColorantEthylhexyl Salicylate
UV AbsorberSilica
AbrasivePolyglyceryl-3 Diisostearate
EmulsifyingLauryl PEG-9 Polydimethylsiloxyethyl Dimethicone
Skin ConditioningDiethylamino Hydroxybenzoyl Hexyl Benzoate
UV FilterDisteardimonium Hectorite
StabilisingEthylhexyl Triazone
UV AbsorberPolymethyl Methacrylate
Sodium Chloride
MaskingCI 77492
Cosmetic ColorantHydroxyacetophenone
AntioxidantPEG-30 Dipolyhydroxystearate
EmulsifyingPhenoxyethanol
PreservativeDimethicone
EmollientGlyceryl Behenate/Eicosadioate
EmollientIsopropyl Myristate
EmollientTriethoxycaprylylsilane
CI 77491
Cosmetic ColorantSynthetic Fluorphlogopite
Isononyl Isononanoate
EmollientParfum
MaskingDimethicone/Vinyl Dimethicone Crosspolymer
Skin ConditioningAluminum Hydroxide
EmollientPolyhydroxystearic Acid
EmulsifyingCI 77499
Cosmetic ColorantEthylhexylglycerin
Skin ConditioningDisodium EDTA
Scutellaria Alpina Flower/Leaf/Stem Extract
Skin ConditioningTin Oxide
AbrasiveCitric Acid
BufferingCentella Asiatica Extract
CleansingNiacinamide
SmoothingOligopeptide-1
Skin ConditioningSqualane
EmollientTocopherol
AntioxidantWater, Cyclopentasiloxane, Butylene Glycol, Homosalate, CI 77891, Glycerin, Cyclohexasiloxane, C12-15 Alkyl Benzoate, Caprylyl Methicone, Trimethylsiloxysilicate, Zinc Oxide, Ethylhexyl Salicylate, Silica, Polyglyceryl-3 Diisostearate, Lauryl PEG-9 Polydimethylsiloxyethyl Dimethicone, Diethylamino Hydroxybenzoyl Hexyl Benzoate, Disteardimonium Hectorite, Ethylhexyl Triazone, Polymethyl Methacrylate, Sodium Chloride, CI 77492, Hydroxyacetophenone, PEG-30 Dipolyhydroxystearate, Phenoxyethanol, Dimethicone, Glyceryl Behenate/Eicosadioate, Isopropyl Myristate, Triethoxycaprylylsilane, CI 77491, Synthetic Fluorphlogopite, Isononyl Isononanoate, Parfum, Dimethicone/Vinyl Dimethicone Crosspolymer, Aluminum Hydroxide, Polyhydroxystearic Acid, CI 77499, Ethylhexylglycerin, Disodium EDTA, Scutellaria Alpina Flower/Leaf/Stem Extract, Tin Oxide, Citric Acid, Centella Asiatica Extract, Niacinamide, Oligopeptide-1, Squalane, Tocopherol
Water
Skin ConditioningGlycerin
HumectantC13-16 Isoparaffin
SolventIsododecane
EmollientDimethicone
EmollientC12-15 Alkyl Benzoate
AntimicrobialTrimethylsiloxysilicate
EmollientIsononyl Isononanoate
EmollientNiacinamide
SmoothingZinc Oxide
Cosmetic ColorantSodium Chloride
MaskingLauryl PEG-10 Tris(Trimethylsiloxy)Silylethyl Dimethicone
Emulsifying1,2-Hexanediol
Skin ConditioningHydroxyacetophenone
AntioxidantPhenylbenzimidazole Sulfonic Acid
UV AbsorberSorbitan Sesquioleate
EmulsifyingTriethoxycaprylylsilane
Parfum
MaskingSilica
AbrasiveAlumina
AbrasiveTocopheryl Acetate
AntioxidantSynthetic Fluorphlogopite
Disteardimonium Hectorite
StabilisingSodium Hydroxide
BufferingDisodium EDTA
Propylene Glycol
HumectantButylene Glycol
HumectantMagnolia Sieboldii Extract
Skin ConditioningOlea Europaea Fruit Oil
MaskingLactobacillus Ferment
Skin ConditioningCeramide NP
Skin ConditioningTin Oxide
AbrasiveCentella Asiatica Leaf Extract
Skin ConditioningCalendula Officinalis Flower Extract
MaskingHibiscus Militaris Flower Extract
Skin ConditioningChrysanthellum Indicum Extract
Skin ConditioningXanthan Gum
EmulsifyingPhenoxyethanol
PreservativeSodium Benzoate
MaskingHydrated Silica
AbrasiveTocopherol
AntioxidantCaprylyl Glycol
EmollientCitric Acid
BufferingEthylhexylglycerin
Skin ConditioningGlucose
HumectantSodium Hyaluronate
HumectantChondrus Crispus Extract
Skin ConditioningHydroxypropyltrimonium Hyaluronate
Hydrolyzed Hyaluronic Acid
HumectantSodium Acetylated Hyaluronate
HumectantHyaluronic Acid
HumectantHydrolyzed Sodium Hyaluronate
Skin ConditioningSodium Hyaluronate Crosspolymer
HumectantPotassium Hyaluronate
Skin ConditioningCI 77891
Cosmetic ColorantCI 77492
Cosmetic ColorantCI 77491
Cosmetic ColorantCI 77499
Cosmetic ColorantWater, Glycerin, C13-16 Isoparaffin, Isododecane, Dimethicone, C12-15 Alkyl Benzoate, Trimethylsiloxysilicate, Isononyl Isononanoate, Niacinamide, Zinc Oxide, Sodium Chloride, Lauryl PEG-10 Tris(Trimethylsiloxy)Silylethyl Dimethicone, 1,2-Hexanediol, Hydroxyacetophenone, Phenylbenzimidazole Sulfonic Acid, Sorbitan Sesquioleate, Triethoxycaprylylsilane, Parfum, Silica, Alumina, Tocopheryl Acetate, Synthetic Fluorphlogopite, Disteardimonium Hectorite, Sodium Hydroxide, Disodium EDTA, Propylene Glycol, Butylene Glycol, Magnolia Sieboldii Extract, Olea Europaea Fruit Oil, Lactobacillus Ferment, Ceramide NP, Tin Oxide, Centella Asiatica Leaf Extract, Calendula Officinalis Flower Extract, Hibiscus Militaris Flower Extract, Chrysanthellum Indicum Extract, Xanthan Gum, Phenoxyethanol, Sodium Benzoate, Hydrated Silica, Tocopherol, Caprylyl Glycol, Citric Acid, Ethylhexylglycerin, Glucose, Sodium Hyaluronate, Chondrus Crispus Extract, Hydroxypropyltrimonium Hyaluronate, Hydrolyzed Hyaluronic Acid, Sodium Acetylated Hyaluronate, Hyaluronic Acid, Hydrolyzed Sodium Hyaluronate, Sodium Hyaluronate Crosspolymer, Potassium Hyaluronate, CI 77891, CI 77492, CI 77491, CI 77499
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:
Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.
Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.
Learn more about Butylene GlycolC12-15 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 BenzoateCi 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 77492Ci 77499 is also hydrated iron III oxide. It is created from mixing red and black iron oxides. This helps give shades of darkness to a product.
Iron III oxides are classified as inorganic chemicals for coloring.
Ci 77891 is a white pigment from Titanium dioxide. It is naturally found in minerals such as rutile and ilmenite.
It's main function is to add a white color to cosmetics. It can also be mixed with other colors to create different shades.
Ci 77891 is commonly found in sunscreens due to its ability to block UV rays.
Learn more about CI 77891Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.
Like other AHAs, citric acid can exfoliate skin by breaking down the bonds that hold dead skin cells together. This helps reveal smoother and brighter skin underneath.
However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.
Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.
In skincare formulas, citric acid can:
While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.
Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.
Read more about some other popular AHA's here:
Learn more about Citric AcidDimethicone is a type of synthetic silicone created from natural materials such as quartz. It is also known as polydimethylsiloxane.
What it does:
Dimethicone comes in different viscosities:
Depending on the viscosity, dimethicone has different properties.
Ingredients lists don't always show which type is used, so we recommend reaching out to the brand if you have questions about the viscosity.
This ingredient is unlikely to cause irritation because it does not get absorbed into skin. However, people with silicone allergies should be careful about using this ingredient.
Note: Dimethicone may contribute to pilling. This is because it is not oil or water soluble, so pilling may occur when layered with products. When mixed with heavy oils in a formula, the outcome is also quite greasy.
Learn more about DimethiconeDisodium EDTA is a chelating agent. It grabs onto and deactivates metal ions that sneak into your products from water, packaging, or air.
This ingredient mainly works behind the scenes and helps with:
On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.
One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).
Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.
You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.
Learn more about Disodium EDTADisteardimonium Hectorite comes from the clay mineral named hectorite. It is used to add thickness to a product.
It can also help stabilize a product by helping to disperse other ingredients.
Hectorite is a rare, white clay mineral.
Learn more about Disteardimonium HectoriteEthylhexylglycerin 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 GlycerinHydroxyacetophenone is antioxidant with skin conditioning and soothing properties. It also boosts the efficiency of preservatives.
Though naturally occuring in Norwegian spruce needles, this ingredient is usually synthetically created.
This ingredient is not irritating or sensitizing. Recent research also suggests it may have skin-brightening effects through tyrosinase inhibition.
Learn more about HydroxyacetophenoneIsononyl Isononanoate is a synthetic skin-conditioner and texture enhancer. It is created from nonanoic acid, a fatty acid found in cocoa and lavender oil.
As an emollient, Isononyl Isononanoate helps keep your skin soft and smooth. This is because emollients create a barrier on the skin to trap moisture in.
Isononyl Isononanoate helps give products a velvet feel and improves spreadability.
Learn more about Isononyl IsononanoateNiacinamide is a multitasking form of vitamin B3 that strengthens the skin barrier, reduces pores and dark spots, regulates oil, and improves signs of aging.
And the best part? It's gentle and well-tolerated by most skin types, including sensitive and reactive skin.
You might have heard of "niacin flush", or the reddening of skin that causes itchiness. Niacinamide has not been found to cause this.
In very rare cases, some individuals may not be able to tolerate niacinamide at all or experience an allergic reaction to it.
If you are experiencing flaking, irritation, and dryness with this ingredient, be sure to double check all your products as this ingredient can be found in all categories of skincare.
When incorporating niacinamide into your routine, look out for concentration amounts. Typically, 5% niacinamide provides benefits such as fading dark spots. However, if you have sensitive skin, it is better to begin with a smaller concentration.
When you apply niacinamide to your skin, your body converts it into nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme that is already found in your cells as "fuel" and powers countless biological processes.
In your skin, NAD helps repair cell damage, produce new healthy cells, support collagen production, strengthen the skin barrier, and fight environmental stressors (like UV and pollution).
Our natural NAD levels start to decline with age, leading to slower skin repair, visible aging, and a weaker skin barrier. By providing your skin niacinamide, you're recharging your skin's NAD levels. This leads to stronger, healthier, and younger looking skin.
Another name for vitamin B3 is nicotinamide. This vitamin is water-soluble and our bodies don't store it. We obtain Vitamin B3 from either food or skincare. Meat, fish, wheat, yeast, and leafy greens contain vitamin B3.
The type of niacinamide used in skincare is synthetically created.
Learn more about NiacinamideParfum is a catch-all term for an ingredient or more that is used to give a scent to products.
Also called "fragrance", this ingredient can be a blend of hundreds of chemicals or plant oils. This means every product with "fragrance" or "parfum" in the ingredients list is a different mixture.
For instance, Habanolide is a proprietary trade name for a specific aroma chemical. When used as a fragrance ingredient in cosmetics, most aroma chemicals fall under the broad labeling category of “FRAGRANCE” or “PARFUM” according to EU and US regulations.
The term 'parfum' or 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term.
For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance by INCI standards.
One example is Calendula flower extract. Calendula is an essential oil that still imparts a scent or 'fragrance'.
Depending on the blend, the ingredients in the mixture can cause allergies and sensitivities on the skin. Some ingredients that are known EU allergens include linalool and citronellol.
Parfum can also be used to mask or cover an unpleasant scent.
The bottom line is: not all fragrances/parfum/ingredients are created equally. If you are worried about fragrances, we recommend taking a closer look at an ingredient. And of course, we always recommend speaking with a professional.
Learn more about ParfumPhenoxyethanol is a preservative that has germicide, antimicrobial, and aromatic properties. Studies show that phenoxyethanol can prevent microbial growth. By itself, it has a scent that is similar to that of a rose.
It's often used in formulations along with Caprylyl Glycol to preserve the shelf life of products.
Silica, also known as silicon dioxide, is a naturally occurring mineral. It is used as a fine, spherical, and porous powder in cosmetics.
Though it has exfoliant properties, the function of silica varies depending on the product.
The unique structure of silica enhances the spreadability and adds smoothness, making it a great texture enhancer.
It is also used as an active carrier, emulsifier, and mattifier due to its ability to absorb excess oil.
In some products, tiny microneedles called spicules are made from silica or hydrolyzed sponge. When you rub them in, they lightly polish away dead skin layers and enhance the penetration of active ingredients.
Learn more about SilicaChances are, you eat sodium chloride every day. Sodium Chloride is also known as table salt. This ingredient has many purposes in skincare: thickener, emulsifier, and exfoliator.
You'll most likely find this ingredient in cleansers where it is used to create a gel-like texture. As an emulsifier, it also prevents ingredients from separating.
You might see people debate whether Sodium Chloride is comedogenic, but there actually haven't been any comedogenic tests done on it. Either way, the overall formulation of a product matters a lot more than any single ingredient.
You might see this ingredient used in scrubs as a primary exfoliating ingredient.
Learn more about Sodium ChlorideSynthetic Fluorphlogopite is the synthethic version of mica. It consists of fluorine, aluminum and silicate.
Synthetic Fluorphlogopite is used to add volume to products.
It is considered non-irritating on the skin.
Learn more about Synthetic FluorphlogopiteTin Oxide is an inorganic oxide used to add opacity and volume to a product. In nature, it is already found in mineral form. The main ore of tin is an opaque and shiny mineral called casseterite.
Tin Oxide helps remove translucency in a product, or make it more opaque. Besides adding opacity, tin oxide is used for bulking to add volume.
Tocopherol 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 TocopherolTriethoxycaprylylsilane is a silicon-based surface modifier that makes sunscreens feel silky and makeup stay put.
Its main job is to coat mineral particles like titanium dioxide, zinc oxide, and color pigments in a thin, oily layer so they spread smoothly, don't clump, and stick to skin better.
This ingredient is typically used at low levels (up to 2.5% in eyeshadow and 1% in lipstick).
Learn more about TriethoxycaprylylsilaneThis silicone is an emollient. Emollients create a thin film on the skin to prevent moisture from escaping.
It is not soluble in water and helps increase water-resistance in products.
According to a manufacturer, it can blend seamlessly with silicone oils, such as Cyclopentasiloxane.
Learn more about TrimethylsiloxysilicateWater. 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