Rohto Mentholatum Sunplay Super Block SPF 130 PA++++

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.

In formulas, it's always paired with a separate UVA filter because octinoxate solely protects skin from UVB.

Because it's an oil-soluble liquid, it's easy to blend into the oil phase of lotions/creams and gives a cosmetically elegant feel.

The one quirk about formulating this ingredient is photostability; the molecule slowly changes shape into a less effective version when sunlight hits it. So the longer you're in the sun, the weaker its protection gets. The drop can be more than 30% in some formulas.

It also doesn't play nice with Avobenzone (the common UVA filter) since avobenzone destabilizes octinoxate and the two degrade each other. But don't worry: brands have solved this issue by adding photostabilizers like Tinosorb S to prevent degradation and keep SPF stable under heavy UV exposure.

The maximum allowed level is 10% in the EU and Australia, 7.5% in the US and Canada, and 20% in Japan.

The Cosmetic Ingredient Review Panel has concluded this ingredient to be safe in cosmetics up to 10%.

One last thing worth knowing for context:

Octinoxate has been the subject of ongoing review in Europe where the Scientific Committee on Consumer Safety's (SCCS) 2025 final opinion is that this ingredient is an endocrine-active substance.

Lab and animal studies suggest it can act a bit like a hormone in the body (mildly mimicking estrogen and slightly blocking male hormones). It's important to know this hasn't really been shown to happen in everyday human use.

This ingredient is also banned in Hawaii over coral reef concerns.

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.

Isononyl Isononanoate helps give products a velvet feel and improves spreadability.

Is it bad for your skin?

The answer comes down to concentration. Patch and wash studies have found highly concentrated alcohol-based hand rubs (60-100%) cause less barrier disruption than washing with a basic detergent like SLS. The only measurable effect in these studies was a temporary dip in skin hydration.

Concentrations below 12-15% in leave-on cosmetics is generally well-tolerated. Concentrations above start to see increased transepidermal water loss (TEWL) and reduced hydration.

In concentrations about 58%, it creates temporary channels in your skin's lipid layers to become more permeable and allow other ingredients to slip through easily.

This ingredient can be up to 80% of the formula in alcohol-based perfumes.

Overall, this ingredient is probably harmless if found lower down an ingredients list but worth side-eyeing if it's high up (especially if your barrier is already struggling).

Alcohol can worsen dry skin, eczema, and oily skin, especially at higher concentrations. This is because it can increase transepidermal water loss and decrease hydration to disrupt the skin barrier.

According to the National Rosacea Society based in the US, you should be mindful of products with these alcohols in the top half of ingredients.

True allergic contact dermatitis to ethanol is uncommon, but be sure to patch test if you have dry or sensitive skin.

It is also an emollient and helps condition the skin.

You'll often see it paired with other UV filters to boost overall SPF because octisalate is a fairly week filter on its own.

The reason you'll see it so often is because it can help solubilize and stabilize the trickier filters like oxybenzone and avobenzone.

Unlike these filters, octisalate has pretty good photostability and doesn't create skin-damaging free radicals when exposed to sunlight.

The fatty-alcohol part of the molecule also gives it a light, emollient feel so it doubles as a nice texture enhancer.

Usage levels vary around the world:

Safety-wise, this ingredient has a pretty reassuring track record. The EU's Scientific Committee on Consumer Products (SCCP) found very low skin penetration in human skin tests and negative results for irritation, phototoxicity, and photoallergy.

The real-world allergy risk is pretty low too; a 2012 European study of 1,031 people recorded only 2 reactions to it (a rate of 0.19%).

You might have seen scary headlines about sunscreen getting into your blood.

In 2019, the FDA found that several chemical filters can absorb through the skin and show up in the bloodstream at small but measurable levels.

Here's the important part: these tiny levels are just a cutoff the FDA uses to decide which ingredients need more testing and doesn't mean anything harmful was found.

The researchers were clear that the results are no reason to stop wearing sunscreen.

Polymethylsilsesquioxane has not been shown to clog pores. It has been deemed safe to use up to 55%, but most cosmetics use much less.

If you have concerns about using this ingredient, we recommend speaking with a professional.

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.

DHHB has been approved by the EU, Japan, Taiwan, and South America for use up to 10%. Unfortunately, it has not been approved for use in the US or Canada due to slow regulatory processes.

This ingredient is soluble in oils, fats, and lipids.

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.

Besides holding formulas together, it also leaves a silky and lightweight feel on skin without the greasiness. A manufacturer also claims it can help with the controlled release of active ingredients.

The CIR Expert Panel found this ingredient to not be sensitizing in concentrations up to 15% in human maximazation testing and dimethicone-based compounds were not comedogenic.

It has a high molecular weight well above 1,000 g/mol which means it limits meaningful skin penetration.

A 2019 study specifically tested this ingredient and found no observable Malassezia growth in its presence.

This ingredient is not water-soluble.

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.

Ethylhexyl Triazone is oil soluble, oderless and colorless, which mean it is able to be incorporated into a variety of different formulations.

It is not currently available within the United States due to slow changing FDA regulations. Outside of the US, it is used in formulations at concentrations up to 5%.

According to a manufacturer, it can blend seamlessly with silicone oils, such as Cyclopentasiloxane.

This ingredient is typically used at low levels (up to 2.5% in eyeshadow and 1% in lipstick).

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.

Another pro?

It's exceptionally photostable, barely degrades in sunlight, and acts as a "bodyguard" for less stable filters.

That's why you'll see it paired with avobenzone or octinoxate; this team up ensures they keep working through sun exposure.

Safety reviews have been reassuring across the board. This ingredient shows low absorption through the skin, rarely irritates, and lab studies found it doesn't act like a hormone in the body (a concern that's been raised about some older sunscreen filters).

On maximum concentrations:

In 2026, the US F.D.A finally added it as an OTC sunscreen ingredient at concentrations up to 6% for adults / children 6 months and older

Tocopheryl Acetate is commonly found in both skincare and dietary supplements.

This is also one of the most heavily studied preservatives out there and major regulatory bodies have repeatedly given it the green light.

In 2023, the EU's Scientific Committee on Consumer Safety (SCCS) confirmed that this ingredient is safe up to 0.4% on its own, of up to 0.8% when mixed with other paraben esters.

Here's the science behind the noise behind parabens/hormones as well:

Methylparaben shows very weak estrogen-like activity in vitro tests (more than 1,000x weaker than your body's own estradiol). In vivo (live-organism) studies don't support a meaningful endocrine-disrupting effect either.

You get a stronger estrogenic effect from eating tofu, actually.

It's also a low sensitizer and allergic reactions are uncommon; they usually happen on damage or broken skin.

There is a caveat: France has proposed to formally re-examine its endocrine classification in 2025 so the regulatory conversation isn't fully closed as of yet.

But as it stands today, this ingredient is considered safe at permitted levels.

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%.

Aloe Barbadensis Leaf Juice also contains sugars. These sugars come in the form of monosaccharides and polysaccharides, folic acid, and choline. These sugars are able to help bind moisture to skin.

It also contains minerals such as calcium, 12 anthraquinones, fatty acids, amino acids, and Vitamin B12.

The CIR Expert Panel has confirmed this ingredient to be nontoxic and clinical studies show no sensitization at cosmetic use concentrations.

True allergic reactions are quite rare: a 15-year retrospective study of 6,751 patients found only 0.31% had a positive reaction (and less than half were considered clinically relevant).

It seemed that when sensitization does occur, it's most commonly linked to topical medication (like corticosteroids) and not cosmetics. Allergic contact dermatitis also appears largely limited to individuals with underlying skin conditions.

Overall, propylene glycol is a well-studied ingredient that most people can tolerate without issue.

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%.

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.

When applied to the skin, ectoin helps bind water molecules to protect our skin. The water forms a sort of armor for the parts of our skin cells, enzymes, proteins, and more.

Besides this, ectoin has many uses in skincare:

A study from 2004 found ectoin to counteract the damage from UV-A exposure at different cell levels. It has also been shown to protect skin against both UV-A, UV-B rays, infrared light, and visible light.

Studies show ectoin to have dual-action pollution protection: first, it protects our skin from further pollution damage. Second, it helps repair damage from pollution.

In fact, ectoin has been shown to help with:

Fun fact: In the EU, ectoin is used in inhalation medication as an anti-pollution ingredient.

Ectoin is a highly stable ingredient. It has a wide pH range of 1-9. Light, oxygen, and temperature do not affect this ingredient.

The chemical name for this ingredient is Tetrahydromethylpyrimidine Carboxylic Acid.

This ingredient is good for soothing sensitive skin.

Many different types of algae have different benefits.