APLB Bakuchiol Propolis Ampoule Serum Versus SKIN1004 Madagascar Centella Probio-Cica Intensive Ampoule

You'll usually find this in concentrations between 0.2-5%.

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.

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.

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.

Acrylic acid itself is toxic, but the polymer form (this ingredient) is too large to penetrate skin, making it non-toxic.

First, it turns down inflammation so it helps with things like redness and general upset skin.

Second, it acts as an antioxidant which means it helps protect skin from daily stress and damage.

And third, it nudges the skin to make more collagen and rebuild its support structure.

That combination is why the whole Centella family is known for calming skin, strengthening the barrier, fading redness, and giving anti-aging benefits.

It's worth being honest about the evidence here; a lot of the strongest data is on the full extract or a Madecassoside/Asiaticoside rather than Madecassic Acid alone. Reviewers also note more long-term clinical trials are needed to confirm the full potential.

Concentration-wise, this ingredient is rarely used pure and usually shows up as part of a standardized centella extract where reported content ranges from 0.02-3.06%.

Finished products typically run somewhere in the 0.1-10% range depending on the format.

In real-world tolerance tests, a repeat-insult patch test on an eye lotion with 0.2% Centella extract showed no irritation or allergic contact dermatitis in 54 subjects. And a mascara with 0.5% Madecassoside caused neither irritation nor sensitization in 109 subjects.

Allergy risk is very low, but not zero. Centella and its constituents are classified as weak contact sensitizers and some rare cases of allergic contact dermatitis exist.

D-panthenol is also known as dexpanthenol. Most cosmetics use dexpanthenol or a mixture of D and L-panthenol.

Panthenol is famous due to its ability to go deeper into the skin's layers. Using this ingredient has numerous pros (and no cons):

Like hyaluronic acid, panthenol is a humectant. Humectants are able to bind and hold large amounts of water to keep skin hydrated.

This ingredient works well for wound healing. It works by increasing tissue in the wound and helps close open wounds.

Once oxidized, panthenol converts to pantothenic acid. Panthothenic acid is found in all living cells.

This ingredient is also referred to as pro-vitamin B5.

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.

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!

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.