Ilia True Skin Serum Concealer Versus bareMinerals Original Liquid Mineral Concealer

Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.

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.

Concentrations up to 100% in guinea pig tests found it to be non-sensitizing and completely safe for use in cosmetics.

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.

This ingredient is very interesting as a hydrator; most moisturizers are either occlusives, humectants, or emollients. Isostearyl isostearate works through another route named "internal occlusion" by the head researcher.

Isostearyl isostearate nudges the skin's own lipids into a denser, more tightly packed arrangement. Packing the deeper layers of the stratum corneum together more efficiently means less water is able to escape.

This is a barrier-improving mechanism that hadn't been described before and plastic occlusion stress tests confirmed it improved the skin's water-permeability barrier function

Just one thing worth noting from the same review: this ingredient increased the penetration rate of a test drug through excised human skin. Though this ingredient is not classified as a penetration enhancer, it does interact with the barrier rather than sitting totally inert on top.

Fungal acne:
The Malassezia yeast feeds on fatty acids and esters in the C11-24 range. Since both halves of this molecules are C18, it may not be fungal acne safe.

Lauroyl lysine is barely soluble in water.

This ingredient may not be fungal acne safe because research has shown that the Malassezia species can grow in the presence of fatty acid esters with chain lengths above C12 (and this one is C18).

While it does have a comedogenic rating of 4, the comedogenic rating scale was developed from rabbit ear models which has limited clinical relevance to human skin. Studies also show that comedogenic ingredients cannot predict how the overall formula will behave on human skin.

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

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.