What's inside
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Skin ConditioningZinc Oxide
Cosmetic ColorantC12-15 Alkyl Benzoate
AntimicrobialPropanediol
SolventTitanium Dioxide
Cosmetic ColorantButylene Glycol
HumectantButyloctyl Salicylate
Skin ConditioningNiacinamide
SmoothingPolyglyceryl-10 Oleate
Skin ConditioningIsononyl Isononanoate
EmollientCaprylyl Methicone
Skin ConditioningDibutyl Adipate
Emollient1,2-Hexanediol
Skin ConditioningPentylene Glycol
Skin ConditioningPyrus Communis Fruit Extract
Skin ConditioningPrunus Persica Fruit Extract
AbrasiveSphingomonas Ferment Extract
Skin ConditioningCucumis Melo Fruit Extract
Skin ConditioningHedera Helix Leaf/Stem Extract
AntimicrobialMoringa Oleifera Seed Extract
Skin ConditioningCardiospermum Halicacabum Flower/Leaf/Vine Extract
Skin ConditioningRosmarinus Officinalis Leaf Extract
AntimicrobialRosa Damascena Flower Water
MaskingJasminum Officinale Flower Water
MaskingSodium Hyaluronate
HumectantRibes Nigrum Seed Oil
EmollientHydrogenated Lecithin
EmulsifyingHelianthus Annuus Seed Oil
EmollientTriethoxycaprylylsilane
Cetearyl Olivate
Polyhydroxystearic Acid
EmulsifyingSorbitan Olivate
EmulsifyingMethylpropanediol
SolventAluminum Hydroxide
EmollientStearic Acid
CleansingDicaprylyl Carbonate
EmollientVp/Eicosene Copolymer
Glycerin
HumectantPolyquaternium-51
Skin ConditioningSodium Polyacryloyldimethyl Taurate
Emulsion StabilisingPolyacrylate Crosspolymer-6
Emulsion StabilisingSodium Stearoyl Glutamate
CleansingEthylhexylglycerin
Skin ConditioningInulin Lauryl Carbamate
Emulsion StabilisingXanthan Gum
EmulsifyingPolyglyceryl-6 Polyricinoleate
EmulsifyingPolyglyceryl-6 Polyhydroxystearate
EmulsifyingAdenosine
Skin ConditioningPanthenol
Skin ConditioningPolyether-1
Polyglycerin-6
HumectantHydrolyzed Hyaluronic Acid
HumectantBiosaccharide Gum-1
HumectantTocopherol
AntioxidantEctoin
Skin ConditioningOctyldodecanol
EmollientMaltodextrin
AbsorbentCeramide NP
Skin ConditioningDipropylene Glycol
HumectantGlyceryl Stearate
EmollientHelianthus Annuus Seed Oil Unsaponifiables
EmollientCeramide As
Skin ConditioningCeramide AP
Skin ConditioningCeramide Ns
Skin ConditioningCholesterol
EmollientCitric Acid
BufferingCeramide EOP
Skin ConditioningCI 77492
Cosmetic ColorantCI 77491
Cosmetic ColorantCI 77499
Cosmetic ColorantWater, Zinc Oxide, C12-15 Alkyl Benzoate, Propanediol, Titanium Dioxide, Butylene Glycol, Butyloctyl Salicylate, Niacinamide, Polyglyceryl-10 Oleate, Isononyl Isononanoate, Caprylyl Methicone, Dibutyl Adipate, 1,2-Hexanediol, Pentylene Glycol, Pyrus Communis Fruit Extract, Prunus Persica Fruit Extract, Sphingomonas Ferment Extract, Cucumis Melo Fruit Extract, Hedera Helix Leaf/Stem Extract, Moringa Oleifera Seed Extract, Cardiospermum Halicacabum Flower/Leaf/Vine Extract, Rosmarinus Officinalis Leaf Extract, Rosa Damascena Flower Water, Jasminum Officinale Flower Water, Sodium Hyaluronate, Ribes Nigrum Seed Oil, Hydrogenated Lecithin, Helianthus Annuus Seed Oil, Triethoxycaprylylsilane, Cetearyl Olivate, Polyhydroxystearic Acid, Sorbitan Olivate, Methylpropanediol, Aluminum Hydroxide, Stearic Acid, Dicaprylyl Carbonate, Vp/Eicosene Copolymer, Glycerin, Polyquaternium-51, Sodium Polyacryloyldimethyl Taurate, Polyacrylate Crosspolymer-6, Sodium Stearoyl Glutamate, Ethylhexylglycerin, Inulin Lauryl Carbamate, Xanthan Gum, Polyglyceryl-6 Polyricinoleate, Polyglyceryl-6 Polyhydroxystearate, Adenosine, Panthenol, Polyether-1, Polyglycerin-6, Hydrolyzed Hyaluronic Acid, Biosaccharide Gum-1, Tocopherol, Ectoin, Octyldodecanol, Maltodextrin, Ceramide NP, Dipropylene Glycol, Glyceryl Stearate, Helianthus Annuus Seed Oil Unsaponifiables, Ceramide As, Ceramide AP, Ceramide Ns, Cholesterol, Citric Acid, Ceramide EOP, CI 77492, CI 77491, CI 77499
Water
Skin ConditioningZinc Oxide
Cosmetic ColorantCaprylyl Methicone
Skin ConditioningButyloctyl Salicylate
Skin ConditioningC9-12 Alkane
SolventDipropylene Glycol
HumectantPropylheptyl Caprylate
EmollientPolyglyceryl-3 Polydimethylsiloxyethyl Dimethicone
Skin ConditioningNiacinamide
SmoothingMethyl Trimethicone
Skin ConditioningDicaprylyl Ether
EmollientTitanium Dioxide
Cosmetic ColorantC12-15 Alkyl Benzoate
AntimicrobialMethyl Methacrylate Crosspolymer
Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer
Disteardimonium Hectorite
StabilisingMagnesium Sulfate
Triethoxycaprylylsilane
Sodium Potassium Aluminum Silicate
1,2-Hexanediol
Skin ConditioningPolyglyceryl-2 Dipolyhydroxystearate
Skin ConditioningLauryl Polyglyceryl-3 Polydimethylsiloxyethyl Dimethicone
Skin ConditioningDimethicone/Vinyl Dimethicone Crosspolymer
Skin ConditioningOctyldodecanol
EmollientSilica
AbrasivePolyhydroxystearic Acid
EmulsifyingDimethiconol
EmollientTrisiloxane
Skin ConditioningCI 77492
Cosmetic ColorantDibutyl Adipate
EmollientPoly C10-30 Alkyl Acrylate
Emulsion StabilisingCaprylyl Glycol
EmollientGlyceryl Caprylate
EmollientNeopentyl Glycol Diethylhexanoate
EmollientEthylhexylglycerin
Skin ConditioningAluminum Hydroxide
EmollientCI 77491
Cosmetic ColorantAdenosine
Skin ConditioningEchium Plantagineum Seed Oil
Skin ConditioningPolymethyl Methacrylate
Helianthus Annuus Seed Oil Unsaponifiables
EmollientCI 77499
Cosmetic ColorantTocopherol
AntioxidantCardiospermum Halicacabum Flower/Leaf/Vine Extract
Skin ConditioningCentella Asiatica Extract
CleansingSea Salt
AbrasiveSaccharomyces Ferment Filtrate
HumectantPropanediol
SolventGlycerin
HumectantAloe Barbadensis Leaf Extract
EmollientButylene Glycol
HumectantBombax Malabaricum Flower Extract
HumectantWater, Zinc Oxide, Caprylyl Methicone, Butyloctyl Salicylate, C9-12 Alkane, Dipropylene Glycol, Propylheptyl Caprylate, Polyglyceryl-3 Polydimethylsiloxyethyl Dimethicone, Niacinamide, Methyl Trimethicone, Dicaprylyl Ether, Titanium Dioxide, C12-15 Alkyl Benzoate, Methyl Methacrylate Crosspolymer, Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer, Disteardimonium Hectorite, Magnesium Sulfate, Triethoxycaprylylsilane, Sodium Potassium Aluminum Silicate, 1,2-Hexanediol, Polyglyceryl-2 Dipolyhydroxystearate, Lauryl Polyglyceryl-3 Polydimethylsiloxyethyl Dimethicone, Dimethicone/Vinyl Dimethicone Crosspolymer, Octyldodecanol, Silica, Polyhydroxystearic Acid, Dimethiconol, Trisiloxane, CI 77492, Dibutyl Adipate, Poly C10-30 Alkyl Acrylate, Caprylyl Glycol, Glyceryl Caprylate, Neopentyl Glycol Diethylhexanoate, Ethylhexylglycerin, Aluminum Hydroxide, CI 77491, Adenosine, Echium Plantagineum Seed Oil, Polymethyl Methacrylate, Helianthus Annuus Seed Oil Unsaponifiables, CI 77499, Tocopherol, Cardiospermum Halicacabum Flower/Leaf/Vine Extract, Centella Asiatica Extract, Sea Salt, Saccharomyces Ferment Filtrate, Propanediol, Glycerin, Aloe Barbadensis Leaf Extract, Butylene Glycol, Bombax Malabaricum Flower Extract
Reviews
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
1,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse.
It is a:
- Humectant, drawing moisture into the skin
- Emollient, helping to soften skin
- Solvent, dispersing and stabilizing formulas
- Preservative booster, enhancing the antimicrobial activity of other preservatives
Adenosine is in every living organism. It is one of four components in nucleic acids that helps store our DNA.
Adenosine has many benefits when used. These benefits include hydrating the skin, smoothing skin, and reducing wrinkles. Once applied, adenosine increases collagen production. It also helps with improving firmness and tissue repair.
Studies have found adenosine may also help with wound healing.
In skincare products, Adenosine is usually derived from yeast.
Learn more about AdenosineAluminum Hydroxide is a form of aluminum. It can be naturally found in nature as the mineral gibbsite. In cosmetics, Aluminum Hydroxide is used as a colorant, pH adjuster, and absorbent.
As a colorant, Aluminum Hydroxide may add opacity, or reduce the transparency. Aluminum hydroxide is contains both basic and acidic properties.
According to manufacturers, this ingredient is an emollient and humectant. This means it helps hydrate the skin.
In medicine, this ingredient is used to help relieve heartburn and help heal ulcers.
There is currently no credible scientific evidence linking aluminum hydroxide in cosmetics to increased cancer risk.
Major health organizations allow the use of aluminum hydroxide in personal care products and have not flagged it as a carcinogenic risk at typical usage levels.
Learn more about Aluminum HydroxideButylene 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 GlycolButyloctyl Salicylate is a chemical UV filter structurally similar to octisalate. It is a photostabilizer, SPF booster, emollient and solvent. This ingredient helps evenly spread out ingredients.
According to a manufacturer, it is suitable for pairing with micro Titanium Dioxide, Zinc Oxide, and pigments.
Photostabilizers help stabilize UV-filters and prevents them from degrading quickly.
Learn more about Butyloctyl SalicylateC12-15 Alkyl Benzoate is made up of Benzoic Acid and long chain alcohols. It has a low molecular weight.
C12-15 Alkyl Benzoate is an emollient and texture enhancer. Due to its solubility, it is often used in sunscreens to help evenly distribute active ingredients.
As an emollient, C12-15 Alkyl Benzoate helps soften and hydrate your skin. Emollients create a film on your skin that traps moisture within.
This ingredient has been reported to cause eye irritation.
Learn more about C12-15 Alkyl BenzoateCaprylyl Methicone is a synthetic and lightweight silicone fluid. It gives products a silky, dry-touch finish without the heaviness of pure oils.
Though the EU CosIng Database lists this ingredient as a skin conditioner, it is also used for sensory reasons. It spreads easily, cuts greasiness, and reduces tackiness.
This ingredient is volatile which means it will mostly evaporate (but it evaporates slower than older cyclomethicones, like Cyclotetrasiloxane).
Typical concentration ranges from 1-30% depending on if it's being used to tweak the feel of a product or acting as the main emollient.
Learn more about Caprylyl MethiconeCardiospermum halicacabum extract is more commonly known as Balloon Vine Extract.
Balloon Vine Extract helps soothe skin and is an antioxidant. It also contains many fatty acids, such as palmitic, oleic, and stearic acids. While these fatty acids help soften skin, they may not be fungal-friendly.
Antioxidants help fight free-radicals. Free-radicals are molecules that may damage your skin cells, such as pollution.
Balloon Vine has been used in traditional medicine in many Asian cultures.
Learn more about Cardiospermum Halicacabum Flower/Leaf/Vine ExtractCi 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.
Dibutyl Adipate is an emollient and solvent. It is created from butyl alcohol and adipic acid.
As a solvent, Dibutyl Adipate helps mix and disperse ingredients evenly.
Dibutyl Adipate is soluble in water and organic solvents. It does not absorb UV rays.
Learn more about Dibutyl AdipateDipropylene Glycol is a synthetically created humectant, stabilizer, and solvent.
This ingredient helps:
Dipropylene glycol is technically an alcohol, but it belongs to the glycol family (often considered part of the ‘good’ alcohols). This means it is hydrating and gentle on skin unlike drying solvent alcohols like denatured alcohol.
As a masking agent, Dipropylene Glycol can be used to cover the smell of other ingredients. However, it does not have a scent.
Studies show Dipropylene Glycol is considered safe to use in skincare.
Learn more about Dipropylene GlycolEthylhexylglycerin 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 GlycerinSunflower seed oil unsaponifiables comes from the the small part of sunflower seed oil that does not convert into soap during the saponification process.
This ingredient is rich in vitamin E, fatty acids (like linoleic acid), and other lipophilic compounds, making it a great emollient. Emollients help keep the skin hydrated and soft.
Due to its rich fatty acid content, this ingredient may not be Malassezia folliculitis safe.
Learn more about Helianthus Annuus Seed Oil UnsaponifiablesNiacinamide 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 NiacinamideOctyldodecanol is a fatty alcohol sourced from plant oils like coconut or palm (or made synthetically).
It is:
You'll likely see this in many BHA products because this is the go-to solvent for salicylic acid.
This ingredient is typically used at levels between 2-20%.
Regarding fungal acne:
In 2019, this ingredient was tested against multiple Malassezia species (the yeast that causes fungal acne) and showed no growth.
Polyhydroxystearic 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 PropanediolTitanium dioxide is a mineral UV filter widely used in sunscreens and cosmetics.
It is one of only two UV filters officially classified as “mineral” by regulatory agencies, the other being zinc oxide.
Titanium dioxide provides broad-spectrum protection mostly in the UVB and UVAII range, with some protection in the UVAI range.
While its UVA protection isn’t as strong as zinc oxide’s, the difference is minor.
A common myth is that mineral UV filters reflect UV light. However, modern research shows titanium dioxide absorbs UV radiation like chemical filters (~95% absorption & 5% reflection).
Thanks to its non-irritating nature, titanium dioxide is suitable for sensitive, acne-prone, or redness-prone skin. It is unlikely to cause "eye sting" like other sunscreen ingredients.
A major drawback of this ingredient is its white cast and thick texture. This is why mineral sunscreens often leave a white cast and are less cosmetically elegant than chemical/hybrid sunscreens.
To improve white cast and spreadability, micronized or nano-sized titanium dioxide is often used.
There are ongoing concerns surrounding nano-titanium oxide's impact on marine ecosystems.
There is no conclusive evidence that any form of titanium oxide (or any other sunscreen ingredients) will cause harm to marine ecosystems or coral reefs. The science is still developing but many consumers are keeping a close eye on this issue.
Please note, many destinations have reef-safety sunscreen rules. For instance, the U.S. Virgin Islands advises all visitors to use non-nano mineral sunscreens.
Nano mineral sunscreens once raised safety concerns about absorption into skin.
Extensive research has shown that they do not penetrate healthy or damaged skin; they remain safely on the surface and the top layer of dead skin (stratum corneum).
You'll likely find titanium dioxide bundled with alumina, silica, or dimethicone. These ingredients help make titanium dioxide highly photostable; this prevents it from interacting with other formula components under UV light.
Learn more about Titanium DioxideTocopherol 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 TriethoxycaprylylsilaneWater. 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 is a mineral broad-spectrum UV filter; it is the broadest UVA and UVB reflector approved by the FDA. It also has skin protectant and skin soothing properties.
Zinc oxide is one of the most effective broad-spectrum UV filters. It protects against UVB, UVAII, and UVAI. In comparison to its counterpart titanium dioxide, zinc oxide provides uniform and extended UVA protection.
Another great benefit? This ingredient is highly photostable so it won't degrade easily under sunlight.
A common myth is that mineral UV filters are widely believed to primarily reflect UV light.
However, modern research shows titanium dioxide absorbs UV radiation like chemical filters (~95% absorption & 5% reflection).
Zinc oxide has great skin soothing properties so you'll likely find this in sunscreens formulated for sensitive skin or babies/children. It is unlikely to cause "eye sting" like other sunscreen ingredients.
Regulatory agencies consider zinc oxide to be non-toxic and safe. It has also been shown to not penetrate the skin.
Unfortunately, this ingredient does leave a visible white cast. This is why mineral sunscreens are often less cosmetically elegant than chemical or hybrid ones.
In cosmetics, zinc oxide can be found in both non-nano and nano-sized forms. The nano version is used to reduce white cast and improve the texture of sunscreen formulas.
There are ongoing concerns surrounding nano-zinc oxide's impact on marine ecosystems and whether it can be absorbed into skin.
Regarding marine ecosystems and coral reefs, there is no conclusive evidence that any form of zinc oxide (or any other sunscreen ingredients) will cause harm. The science is still developing but many consumers are keeping a close eye on this issue.
Please note, many destinations have reef-safety sunscreen rules. For instance, the U.S. Virgin Islands advises all visitors to use non-nano mineral sunscreens.
There has also been some stir about whether micronized or nano zinc oxide has potential photoxicity and absorption through the skin/lungs.
An in-vitro (done in a test tube or petri dish) study demonstrated micronized zinc oxide to have potential phototoxicity. There's no need to fret; the EU Commission's Scientific Committee on Consumer Safety has stated, "The relevance of these findings needs to be clarified by appropriate investigations in vivo." Or in other words, further studies done on living organisms are needed to prove this.
Current research shows zinc oxide nanoparticles do not penetrate intact or sunburned skin. They either remain on the surface or in the outermost layer of dead skin (stratum corneum).
Zinc oxide is one of only two classified mineral UV filters with titanium dioxide being the other one.
Fun fact: Zinc has been used throughout history as an ingredient in paint and medicine. An Indian text from 500BC is believed to list zinc oxide as a salve for open wound. The Ancient Greek physician Dioscorides has also mentioned the use of zinc as an ointment in 1AD.
Learn more about Zinc Oxide