My Scheming 7% Alpha Arbutin Whitening Serum

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.

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.

Dipropylene glycol is technically an alcohol, but it belongs to the glycol family (often considered part of the ‘good’ alcohols). This means it is hydrating and gentle on skin unlike drying solvent alcohols like denatured alcohol.

As a masking agent, Dipropylene Glycol can be used to cover the smell of other ingredients. However, it does not have a scent.

Studies show Dipropylene Glycol is considered safe to use in skincare.

Curcumin also has anti-inflammatory properties and can help soothe skin and reduce irritation. On top of that, curcumin has been shown to help prevent hyperpigmentation from sun damage.

The anti-microbial property of turmeric can make it effective in treating acne. This property has also been shown to help regulate the production of sebum.

This ingredient is not irritating or sensitizing. Recent research also suggests it may have skin-brightening effects through tyrosinase inhibition.

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 more of a microbiome agent rather than an active; it helps rebalance the skin's microbial community.

The bacteria and their metabolites produce lactic acid and other antimicrobial compounds that crowd out the "bad bacteria". Research on Lactobacillus strains shows activity against pathogens and acne-causing bacteria.

One strain, Lactobacillus plantarum, has also been shown to boost collagen synthesis and lower melanin synthesis in lab and clinical observation.

The most eye-catching data comes from acne research, a topical cream with live lactobacilli was well-tolerated and improved skin hydration by 37.3% after 14 days of use and 45.6% after 28 days.

Sources for this ingredient are usually fermented substrates like dairy, soy, or rice.

In general, this is a low-irritation and well-tolerated ingredient that plays nice with most of your routine.

One thing to keep in mind is that live bacteria are hard to keep alive inside of a skincare product. They struggle to survive on the shelf and don't get along with the preservatives that stop products from spoiling.

That's why you'll see ferment and postbiotic forms instead, like Lactobacillus Ferment or Lactobacillus Ferment Lysate.

There isn't a fixed percentage for this ingredient since it is dosed by strain and viable count.

On the fungal acne front: Lactobacillus is a bacterium (not a fungus). The whole culture contains no fatty acids, esters, or oils that Malassezia can feed on so it is considered fungal acne safe.

Typical usage levels in cosmetics are usually low and in the range of 0.015 - 2.3%.

The common safety discussion around this ingredient involves a manufacturing byproduct called 1,4-dioxane.

Trace amounts can form during production but the EU's Scientific Committee on Consumer Safety has concluded that levels at/below 10 ppm in finished products are safe (commercial products consistently fall within acceptable margins).

True allergic reactions are uncommon and the CIR Expert Panel has confirmed this ingredient to be safe as used in cosmetics.

Because it is derived from lauric acid, it may not be fungal acne safe.

Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.

On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.

One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).

Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.

You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.

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

Tocopheryl Acetate is commonly found in both skincare and dietary supplements.