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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.

In cosmetics, it acts as a skin conditioner, occlusive, and emollient that give products a rich body.

Concentrations are reported from 0.0004% to 60% with leave-on products going as high as 60% and rinse-off products staying at 8% or below.

The Cosmetic Ingredient Review has concluded this ingredient to be safe as used in cosmetics.

This ingredient does have a comedogenic rating of 3, but this doesn't mean a formula with this ingredient will clog pores. Human testing has proved that any finished product with this ingredient won't automatically make you break out; it really comes down to concentration, formula, and your skin.

Since this ingredient is a triglyceride built mostly from C16 and C18 fatty acids, this ingredient may not be fungal acne safe as that falls into the range the Malassezia yeast can metabolize.

Allergy-wise, the proteins responsible for plant food allergies are taken out of the refined oil. This is why reactions to refined oils are rare even from highly allergenic sources like peanut. Well-designed studies have also shown refined peanut oil is safely tolerated by the vast majority of peanut-allergic people.

However, the issue is with unrefined oils; be sure to reach out to the manufacturer if you have a plant food allergy about the type of oil used in their products.

The other catch for this INCI name is that it doesn't tell you which plants are in the blend so you would need to ask the brand.

It is important to note this ingredient comes from the lacquer tree which is in the same plant family as poison ivy or poison oak. Though this ingredient comes from the wax instead of sap (the sap contains the substance that causes itchy rashes), there is a very small chance that sensitive people could react.

Emulsifiers prevent ingredients from separating.

Fun fact: This wax has the highest melting point of all natural waxes and low solubility.

A really common myth is that mineral filters work by reflecting UV light off your skin like tiny mirrors.

They don't only do that; modern research shows TD protects mostly by absorbing UV radiation, the same way chemical filters do.

When researchers measured this, reflection accounted for only about 4-5% of the protection (and less than SPF 2 on its own). The other ~95% comes from absorption: the UV photons hit the particle and their energy gets soaked up by its semiconductor band gap rather than bouncing off.

So "reflects vs. absorbs" was never really the right way to split mineral from chemical filters.

TD gives broad-spectrum protection that's strongest in the UVB and UVA-2 range and weaker in the UVA-1 range. Its UVA protection isn't quite as strong as Zinc Oxide's which is why you'll often see the two paired together.

Together, they make a solid broad-spectrum system.

TD is a great pick for sensitive, acne-prone, or redness-prone skin because it's non-irritating and chemically inert. Regulatory reviews classify it as a non-sensitizer and mild-to-non-irritant.

It's also unlikely to cause the "eye sting" some chemical filters are known for.

The main trade-off is cosmetic; TD can leave a white cast and has a thicker texture. This is why mineral sunscreens are often less cosmetically elegant than chemical or hybrid formulas (and harder to shade-match on deeper skin tones).

Formulators often use micronized or nano-sized TD to cut down on white case and improve spreadability. Smaller particles scatter less visible light so the formula looks less chalky while still filtering UV.

TD is almost always bundled with coatings like Alumina, Silica, Stearic Acid, or Dimethicone. These coatings do two important jobs:

TD can be used at up to 25% in a finished sunscreen; this is the regulatory ceiling in both the US and the EU.

In practice, the amount in any given product varies a lot depending on the target SPF and whether it's paired with other UV filters.

TD is one of the most heavily vetted sunscreen ingredients out there. It is approved as a UV filter in all major markets worldwide, including the US, EU, UK, Japan, Korea, China, Australia, and Canada.

The safety evidence is solid. There was an old worry that nano particles might absorb through skin into the body but multiple studies (including on damaged, sunburned, and UV-irradiated skin) have shown that TD stays on the surface and the layer of dead skin cells on top of everything else.

There's also no evidence of carcinogenicity, mutagenicity, or reproductive toxicity from dermal exposure of this ingredient.

For those who have seen the headline about a 2022 EU ban on TD, that was on TD as a food additive (a complete separate use from topical sunscreen).

There are ongoing questions about how nano-TD might affect marine ecosystems. As of now, there has been no conclusive evidence that any form of TD (or any other sunscreen filter) harms coral reefs or marine life.

The science is still developing and it's a space worth watching rather than packing over.

However, several destinations have reef-safety sunscreen rules that restrict certain chemical filters and steer visitors toward mineral, non-nano options. If you're traveling somewhere with these rules, a non-nano mineral sunscreen is the safe bet.

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.

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.

Some people may experience allergies from this dye, especially asthmatics and those with an aspirin intolerance.