Revolution Beauty Hydra Cool Baking Powder

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.

This ingredient is often coated with metal oxides like titanium dioxide. Trace amounts of heavy metals may be found in mica, but these metals are not harmful in our personal products.

Mica has been used since prehistoric times throughout the world. Ancient Egyptian, Indian, Greek, Roman, Aztec, and Chinese civilizations have used mica.

This is also one of the most heavily studied preservatives out there and major regulatory bodies have repeatedly given it the green light.

In 2023, the EU's Scientific Committee on Consumer Safety (SCCS) confirmed that this ingredient is safe up to 0.4% on its own, of up to 0.8% when mixed with other paraben esters.

Here's the science behind the noise behind parabens/hormones as well:

Methylparaben shows very weak estrogen-like activity in vitro tests (more than 1,000x weaker than your body's own estradiol). In vivo (live-organism) studies don't support a meaningful endocrine-disrupting effect either.

You get a stronger estrogenic effect from eating tofu, actually.

It's also a low sensitizer and allergic reactions are uncommon; they usually happen on damage or broken skin.

There is a caveat: France has proposed to formally re-examine its endocrine classification in 2025 so the regulatory conversation isn't fully closed as of yet.

But as it stands today, this ingredient is considered safe at permitted levels.

It works by disrupting microbial cell membranes and enzymes, and is a broad-spectrum protector that works exceptionally well against molds, yeasts, and gram-positive bacteria.

You'll likely see it paired with methylparaben to cover the full range (including gram-negative bacteria).

This ingredient is effective at low concentrations (~0.2-0.5%) and stable across a wide pH range (4.5-7.5 pH). It's effectiveness drops off above pH 8 and it can lose potency when combined with non-ionic surfactants like polysorbate 80 due to micellization.

The regulatory bodies have concluded this ingredient to be safe as used in cosmetics. The EU has capped it at 0.14% and combined parabens are not to exceed 0.8%.

While parabens do cross the stratum corneum, only about 1% remains for absorption into the body. This is because most of it is metabolized within living skin.

Interestingly, the size of the molecule affects its behavior:

Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.

Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.

You'll typically see concentrations between 0.1-2% for this ingredient.

This ingredient is typically used at low levels (up to 2.5% in eyeshadow and 1% in lipstick).

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.