_faace Period Faace Face Mask

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.

It is non-ionic and forms a triple helix in solution. This is just a fancy way of saying it builds a smooth, cushiony, and non-sticky gel that feels silkier than many other gums.

Another perk of this ingredient is that it is very sturdy and holds up across a wide pH range (~2-11). It's also good at resisting heat and hydrolysis.

Since it holds water at the skin surface, it can provide some light hydration as well.

Typical use levels are around 0.25-2%; formulators usually use 0.2-0.5% to thicken lotions and up to 2% for a firmer gel base.

This ingredient has been found safe in cosmetics with no meaningful evidence of skin sensitization.

Beyond hydration, Biosaccharide Gum-1 gives formulas a silky, non-sticky feel.

This ingredient is gentle, versatile, and suitable for all skin types.

Fun fact: Similar sugars can be found naturally in fruits like apples and pears.

Xanthan gum is a pretty common and great ingredient. It is a natural, non-toxic, non-irritating ingredient that is also commonly used in food products.

This ingredient is considered safe for use and concentrations range from 0.5-62%.

Caprylic and capric fall outside the C11-24 range that Malassezia feeds on, and a 2020 study found caprylic acid disrupted Malassezia furfur cell membrane, with a caprylic acid derivative damaging membrane structures at concentrations as low as 0.2%.

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.

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.

Studies show green tea extract and its catechins (like epigallocatechin gallate (EGCG)) help your skin cells product energy more efficiently and reducing the number of free-radicals that can damage your skin from the inside.

In lab-grown skin models, this translated to younger, healthier, and stronger skin.

There's also good sun protection data; researchers saw less DNA damage and redness on human skin when green tea was applied before UVB exposure. And the more they applied, the better the protection.

Needless to say, this ingredient shouldn't replace your sunscreen. But it is a great supportive ingredient that you can already find in many sunscreens and antioxidant serums.

A 2009 study found a 2% green tea lotion was effective for mild-to-moderate acne thanks to its anti-inflammatory and mild antimicrobial activity.

The quality of the extract matters a lot here:

Good extracts contain 50-90% catechins while lower quality ones are mostly there for marketing. We recommend reaching out to the brand if you have questions about the quality or source of their ingredients.

Human Repeated Insult Patch Testing showed no irritation or sensitization at use concentrations (0.86% in leave-on products and up to 30% as leaf water).

Many components of tea have anti-inflammatory and antimicrobial properties. Polyphenols and L-theanine help soothe the skin and reduce irritation. L-theanine is an amino acid that makes up most of the amino acids found in tea leaves. The caffeine in Camellia Sinensis Leaf Extract helps calm inflamed blood vessels.

Tea leaves also contain Vitamin Bs, linoleic acid, magnesium, calcium, iron, and zinc.

Research has shown both drinking Camellia Sinensis Leaf Tea and applying it to the skin can help boost skin elasticity and hydration. Studies also show using tea extract may reduce sebum, or oil, production.

The zinc part slows down an enzyme that turns testosterone into DHT, the hormone that tells your oil glands to pump out more sebum. Less of that signal means less oil. It also gently fights acne-causing bacteria and soothes redness/irritation.

This is why Zinc PCA often shows up in products for oily, breakout-prone skin and greasy scalps.

One lab study also hinted it might have a small anti-aging perk because it seemed to protect collagen from UVA damage and even helped the skin make a bit more of it. That last bit is still early research done in a dish and not real skin, so take it as a nice bonus rather than a promise for now.

As for scar healing, the picture is more "maybe" than a firm yes. Zinc itself plays a real role in wound repair because it is a cofactor for the enzymes involved in collagen building, calming inflammation, and helping new skin cells cover a wound. Lower zinc levels are also linked to slower healing.

Most of the scar healing research is on zinc oxide or oral zinc rather than zinc PCA specifically, with a focus on healing fresh wounds instead of scars that are already there.

Direct evidence that zinc PCA improves the look of established scars is still limited at this time. Though it would be fair to say zinc PCA supports the general skin-repair environment thanks to its zinc content .

This ingredient is water-soluble and plays nicely with other actives like niacinamide and salicylic acid. It works best at mildly acidic formulas (~4-6 pH) and is effective at low levels. Around 0.1% is enough to be active and finished products commonly use it anywhere up to 4%.

Overall, this is a well-tolerated, low-drama multitasker that suits oily and acne-prone skin.

When exposed to air, these two compounds become strong allergens. This ingredient exhibits cytotoxicity at low concentrations; amounts of 0.25% have been shown to damage skin cells.

Citrus peel is also a rich source of flavonoids. Flavonoids are natural antioxidants and help protect your skin against damage. Flavonoids are a group of compounds naturally found in vegetables and fruits.

The term 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term. For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance.

This ingredient is water-soluble.

Linoleic acid helps maintain skin barrier integrity and is a building block for the ceramides in your stratum corneum. Notably, people with acne tend to have lower linoleic acid in their skin lipids as well (and this gets worse as acne gets more severe).

Overall, it's a lightweight, fast-absorbing oil that has a long safety track record. Lab testing has found it to be non-irritating for skin or eyes.

The Malassezia yeast can metabolize the fatty acids in this oil to grow; therefore this ingredient may not be fungal acne safe.

A patch test is recommended before use, especially for sensitive skin. This ingredient should be diluted as part of a formulation and not applied directly.

Terpinen-4-ol is responsible for tea tree oil's broad-spectrum antimicrobial activity and makes it a well-researched option for acne.

Clinical studies support 5% tea tree oil as an effective topical treatment for mild to moderate acne. A study with 124 patients compared 5% tea tree oil gel to 5% benzoyl peroxide and both reduced acne (though tea tree oil worked more slowly).

Besides acne, it is also seen in anti-dandruff shampoos and scalp treatments for it's antimicrobial and anti-seborrheic properties.

Safety-wise, the allergic potential of low concentrations on healthy skin is considered low. However, oxidized (old or improperly stored) tea tree oil is a stronger sensitizer.

Irritation can also occur if using the undiluted oil on skin; it's best to use this ingredient as part of a carefully crafted cosmetic formula. This is because regulations require tea tree oil in cosmetics to be stabilized to prevent degradation.

This ingredient has been deemed safe up to 2% in shampoo, 1% in cleansers, and 0.1% in face cream by the EU's Scientific Committee on Consumer Safety (SCCS).

There is some lab evidence that tea tree oil is antifungal against Malassezia, but it is a supportive option at best and not a replacement for proven antifungal treatments.

As a preservative, it works by disrupting the membrane of microbial proteins. This helps keep bacteria and fungi from growing in your products.

The sensitization picture is actually quite assuring as well:of nearly 71,000 patients patch tested with benzyl alcohol, only 0.21% showed a positive reaction with most of them being weakly positive.

This led researchers to conclude that benzyl alcohol cannot be regarded as a significant contact allergen.

It is worth noting this ingredient is classified as one of the EU's regulated fragrance allergens and restricted to 1% in finished products.

Labels must also declare it in concentrations above 0.001% in leave-on products and 0.01% in rinse-off products.

At concentrations around 5%, localized redness and itching can appear as a direct irritant response and not as a true allergic reaction.

Limonene acts as an antioxidant, meaning it helps neutralize free radicals.

When exposed to air, oxidized limonene may sensitize the skin. Because of this, limonene is often avoided by people with sensitive skin.

The term 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term. For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance.

This ingredient has a scent that is floral, spicy tropical, and citrus-like.

Besides cosmetics, eugenol is also added as a flavor in teas and cakes.