COOLA Dew Good Illuminating Serum Sunscreen Versus Makeup by Mario Master Mattes Eyeshadow Palette The Neutrals

Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).

Due to its structure as flat, plate-like crystals that stack like tiles, it feels silky and sticks to skin well. This also makes it very chemically stable and insoluble under normal skin conditions (this just means it sits on top of skin rather than going into it).

It has an interesting quirk: it slowly goes gray in sunlight and the graying is partly reversible in the dark.

At this time, there's no legal cap on how much a brand can use. Both the FDA and the EU permit it without restriction so real-world concentration levels come down to formulation:

Allergy risk is low as well since it's insoluble and doesn't release free metal ions into skin. True allergic contact dermatitis to it is rare enough that there's very little published cases.

However, mineral makeup users do report itching or stinging. The leading explanation for this is irritation from those stiff platelet crystals rubbing on skin (also more likely with heavy, high-percentage loose mineral powders) rather than an immune reaction.

This ingredient shows up on a lot of "pore-clogging" lists but there's no real evidence behind that. It doesn't even have a comedogenic rating from an actual study; the numbers you'll find online come from blogs citing other blogs.

Some people still find it breaks them out. So if that's you, definitely trust your skin.

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.