Simka Sheer Mineral Milk SPF 50

Simka Sheer Mineral Milk SPF 50

This mineral sunscreen covers the full UV range and blocks ~98% of UVB at SPF 50.

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What's inside

Key Ingredients

Benefits

Concerns

Ingredients Explained

Cosmetic Colorant, Skin Protecting, UV Absorber

Zinc 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
Emollient, Skin Conditioning

Coco-Caprylate/Caprate is a lightweight ester created from coconut oil fatty acids, caprylic acid, and capric acid.

It is an emollient that helps soften skin and reduce transepidermal water loss (TEWL). What sets it apart from heavier emollients is its ultralight, non-greasy feel.

Once applied, this ingredient dries down quickly and leaves a dry, silky finish behind. This also helps improve spreadability and texture.

This ingredient has an excellent safety-record and is non-irritating.

Typical concentrations for cosmetics range from 0.5-62%.

Research on Malassezia growth found no growth on fatty acid esters with chain lengths shorter than 12 carbons (it prefers C11-24).

Since Coco-Caprylate/Caprate is built on C8 and C10 fatty acids, it is out of the range that Malassezia metabolizes, and therefore safe for fungal acne.

Learn more about Coco-Caprylate/Caprate
Masking, Skin Conditioning

Caprylic/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 Triglyceride
Skin Conditioning, UV Absorber, UV Filter

This ingredient is a photostabilizer and a chemical UV booster. It is marketed as an alternative to octocrylene.

You'll most likely find it in sunscreens to enhance stability and effectiveness of UV filters, antioxidants, and vitamin A derivatives. According to the manufacturer, this ingredient is better than octocrylene at stabilizing avobenzone.

Due to regulation loopholes, you'll likely see this ingredient in "100% mineral" sunscreens.

Learn more about Ethylhexyl Methoxycrylene
Emollient, Skin Conditioning

Undecane is an emollient and helps create a lightweight base for products.

Is is not soluble in water and naturally occurring in some species.

Skin Conditioning, Solvent, UV Filter

Butyloctyl 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 Salicylate
Masking, Perfuming, Skin Conditioning

This ingredient is also known as castor oil. It is a skin conditioning ingredient.

The star component of castor oil is ricinoleic acid, an unusual fatty acid that makes up ~80-92% of its composition.

In skincare, it is an emollient that dries down to a solid film with water-binding properties. This helps keep skin hydrated and helps reduce transepidermal water loss (TEWL).

A 2026 dermatology review pulls together its broader uses:

Human clinical testing found this ingredient to be non-irritating and non-sensitizing.

Because castor oil contains fatty acids in the C11-24 range, this ingredient may not be fungal acne safe.

At this time, the literature does not support castor oil in regrowing hair. A 2022 systematic review found no strong evidence that it supports hair growth and only weak evidence that it improves hair shine.

Castor oil itself carries "perfuming" and "masking" function tags according to the official CosIng database. This is because of its mild odor and odor-dampening properties.

Learn more about Ricinus Communis Seed Oil
Abrasive, Absorbent, Cosmetic Colorant

Kaolin is a clay. It is used for oil control and to help minimize pores. Like other clays, kaolin has the ability to absorb excess sebum or oil. This can help clean out pores and mattify the skin.

Some types of kaolin may have exfoliating properties. When water is added to kaolin, it becomes a paste with small abrasive particles.

Most kaolin is a white color, but may be pink/orange/red depending on where it comes from.

The name 'kaolin' comes from a Chinese village named 'Gaoling'. Kaolin clay comes from rocks rich in kaolinite. Kaolinite, the mineral, has a silicate layered structure. Kaolinite is formed from chemical weathering of aluminum siilicate minerals.

Besides skincare, kaolin is commonly used to make glossy paper, in ceramics, toothpaste, and as medicine to soothe stomach issues.

Learn more about Kaolin
Perfuming

Tridecane is a lightweight emollient and fragrancing ingredient. It is a paraffin and often called a silicone alternative.

According to official INCI guidelines, this ingredient is used to give a light odor to raw materials. It is often used as a starter ingredient to create parfum.

This ingredient can be derived from palm oil, or coconut oil. It is also naturally found in certain species of organisms.

According to the NOAA, this ingredient can cause skin sensitivity with prolonged use. However, this warning is taken from the Coast Guard and no studies have been done on this in relation to cosmetics.

Tridecane is not water soluble.

Learn more about Tridecane
Skin Conditioning

Trihydroxystearin is what you get when you fully hydrogenate castor oil into a waxy, fine powder.

It's mostly a behind-the-scenes texture enhancer that's especially good at "thixotropic" thing where the product stays thick but applies nicely.

Because of its structure, it also acts as a mild skin conditioning emollient that helps soften skin while preventing moisture loss.

Safety studies show it to be safe and non-irritation in clinical tests. It's typically used in concentrations up to 5%.

Since its an ester of a C18 fatty acid, it falls into the C11-24 range that Malassezia can potentially feed on. This makes it not fungal-acne safe.

Learn more about Trihydroxystearin

Polyglyceryl-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 Polyricinoleate
Antioxidant, Skin Conditioning, Skin Protecting

This ingredient is an antioxidant that helps protect skin from environmental stress, like pollution and UV-related damage. It works by neutralizing free radicals.

According to the manufacturer, this ingredient can also help stabilize formulas and especially sunscreens or products that contain UV filters. It helps products stay effective for longer by protecting other ingredients from breaking down when exposed to light.

Some research also suggests it can help reduce excess oil or sebum and calm redness.

Learn more about Bis-Ethylhexyl Hydroxydimethoxy Benzylmalonate
Emollient, Skin Conditioning

Squalane 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 Squalane
Cleansing, Emulsifying, Surfactant

Isostearic Acid is a fatty acid and a structural cousin of stearic acid. It is an emulsifier.

The branched structure of this ingredient enhances fluidity and gives it a lighter, less greasy feel compared to other fatty acids. It helps improve texture and consistency because it prevents oil and water phases from separating.

This ingredient is sourced from plant-based oils like soybean or rapeseed.

Clinical studies found no signs of irritation from this ingredient.

Since Isostearic Acid is an 18-carbon fatty acid, it is in the range that Malassezia can feed on. This ingredient may not be fungal acne safe.

You might have seen sources that this ingredient is comedogenic. The original comedogenic testing on rabbit ear actually tested the ester, Isopropyl Isostearate and not Isostearic acid itself. There has been no comedogenic testing done on this ingredient, but it may be worth patch testing if you have acne-prone skin.

Learn more about Isostearic Acid
Antioxidant, Emollient, Skin Conditioning

Ascorbyl Tetraisopalmitate is a version of ascorbic acid, or Vitamin C.

This ingredient has many benefits including reducing wrinkles, skin soothing, dark spot fading, and fighting against free radicals.

It helps with dark spot fading by interfering with the process of skin darkening, helping to reduce hyperpigmentation. Like other forms of vitamin C, this ingredient encourages the skin to create more collagen.

As an antioxidant, it helps fight free-radicals. Free-radicals are molecules that may damage your skin cells.

One study found Ascorbyl Tetraisopalmitate to degrade in sunlight, but is stabilized when combined with acetyl zingerone.

Learn more about Ascorbyl Tetraisopalmitate
Cosmetic Colorant

Zinc Stearate is the metal salt of stearic acid. It is a white solid used to bind, thicken, and lubricate products.

This ingredient is common in powder makeup, where it helps keep the powder together.

Zinc Stearate is hydrophobic and repels water.

This ingredient can be sourced from non-animal or animal sources. It is best to reach out to the brand to see where they source this ingredient from.

Learn more about Zinc Stearate

Euphorbia Cerifera Wax (aka candelilla wax) is a vegan stand-in for beeswax. It is a plant-derived wax that functions as an astringent, emulsion stabilizer, film-former, and skin conditioner.

On skin, it forms a protective barrier that helps lock in moisture while it enhances product stability, prevents separation, and helps color last longer in makeup.

This ingredient is generally safe for use in cosmetics with one nuance: some grades of candelilla wax can naturally contain benzyl alcohol at concentrations high enough to require declaration under EU labeling rules. This isn't a concern for most people but relevant for those with fragrance sensitivities.

Candelilla wax contains fatty acids (mainly C31) and wax esters that can be used by the Malassezia yeast, so this ingredient may not be fungal acne safe.

You might see Euphorbia Cerifera "Cera" instead of "wax". This is because some brands, databases, or labels use it interchangeably; they're the same ingredient.

Learn more about Euphorbia Cerifera Wax

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Where it's from

Simka is a Australian brand

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50 SPF Rating

With an SPF rating of 50, this product protects against 98.0% of UVB rays

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· Updated November 28, 2025 Added by natasharobinson1