Embryolisse Lait-Crème Retinol-Like Versus Kiehl's Ultra Facial Moisturizer

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

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.

Vitamin E is also prevalent in this ingredient and the most dominant form is gamma-tocopherol.

These compounds give the ingredient emollient and skin conditioning properties that keep the skin soft and hydrated.

There's no regulatory maximum cap for this ingredient so you'll see it across a huge concentration range (100% as a single ingredient facial oil).

On allergies: refined cosmetic-grade oils carry almost no protein. The CIR notes that people allergic to a food generally do not react to the refined oil because the allergenic protein does not partition into it (though cold-pressed grades retain more).

However, it's worth patch testing if you have a stone fruit or tree nut allergy because manufacturer processes for removing the protein can vary.

Malassezia lacks the cytosolic fatty acid synthase gene so the yeast cannot make palmitate on its own and instead uses lipases and phospholipases to release fatty acids from host lipids. Since apricot kernel oil is entirely C16-18 (right in the usable range of C11-24), this ingredient may not be fungal acne safe.

Old rabbit-ear testing did assign this ingredient a comedogenic rating of 1-2. The original author has stated that testing on rabbit ears is not an ideal model for human comedogenicity.

Human testing has proved that any finished product with a comedogenic ingredient won't automatically make you break out; it really comes down to concentration, formula, and your skin.

Just know high-oleic oils tend to feel heavier on oily skin so it's worth patch testing.