Beauty of Joseon Relief Sun Aqua-Fresh Rice + B5 SPF 50+ Versus Wellage Real Hyaluronic Blue Sun Cream SPF 50+

Photostabilizers help stabilize UV-filters and prevents them from degrading quickly.

It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.

Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.

A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.

This ingredient has been found to be safe as used in cosmetics, wasn't a skin or eye irritant in clinical patch testing, and wasn't phototoxic.

In a clinical comedogenicity test, this ingredient tested negative so it isn't likely to clog pores.

Typical use levels are about 5-8% for sunscreens + nail products, but can range from 0.005%-8% depending on the product.

Formulators love it for its stability; its ability to filter UV stays practically unchanged even under intense radiation and it can also help boost the photostability of less stable filters like avobenzone.

It's also a great pick for water resistant products because it's insoluble in water and has a good affinity for keratin.

Because it's a big, heavy molecule, the European Scientific Committee has found to to have very low dermal penetration and negative results for allergenicity.

In vitro testing also showed a low absorption rate and clean results on irritation.

Typical use levels are 1-5% with 5% being the maximum in the EU, Japan, and other markets that allow it. However, this ingredient is not approved yet in the US or Canada.

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.

This ingredient is an emollient, emulsifier, and penetration enhancer. As an emollient, it helps soften and hydrate skin by trapping moisture within. As an emulsifier, it prevents oil and water ingredients from separating.

Hydrogenated Lecithin can form tiny spherical structures made of phospholipid bilayers called liposomes. These liposomes are able to capture compounds inside their structure and deliver them through the skin barrier.

Because phospholipids are a natural component of our cell membranes, this ingredient is inherently compatible with skin.

A 2021 study found lecithin-based surfactants were less harsh and more tolerable comared to Sodium Lauryl Sulfate (SLS).

Methylpropanediol is able to add a bit of moisture to the skin. It also helps other ingredients be better absorbed into the skin, such as salicylic acid.

On the safety side, the Cosmetic Ingredient Review Expert Panel has concluded this ingredient to be safe as used in current cosmetic practices + concentrations.

Typical use levels in a formula run about 1-5%.

Polymethylsilsesquioxane has not been shown to clog pores. It has been deemed safe to use up to 55%, but most cosmetics use much less.

If you have concerns about using this ingredient, we recommend speaking with a professional.

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.

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 peak absorption happens to be the exact type of UVA light that sinks deepest into skin and does the most to cause aging and dark spots.

Ecamsule works by soaking up UV rays and turning them into a tiny bit of harmless heat. The molecule basically flips, releases that energy as heat, then snaps back to its original shape and does it all over again. This is also why it's so stable in sunlight and doesn't break down or wear out the way some filters do.

The clinical backing for this ingredient is solid as well:

A large 2008 review by Fourtanier & colleagues (2008) pulled together human trials showing ecamsule-containing sunscreens prevented UV-induced pigmentation, DNA damage, and signs of aging.

That built on earlier work by Seite et al. (1998) that found it protected skin from repeated low-level UVA exposure. And a controlled study by DeLeo et al. (2009) showed that even an SPF 40 cream with ecamsule helped prevent sun-triggered rash even under the real sun.

On concentrations:

Because this ingredient is an acid, it has to be neutralized so it doesn't tank the product's pH.

Safety-wise, it's pretty well tolerated. There are some rare cases of mild irritation mostly in people with sensitivities towards camphor derivatives.

A 2019 FDA study found that volunteers who slathered on sunscreen heavily for several days had tiny amounts of ecamsule show up in their blood. This was slightly above the level at which the FDA asks for extra safety testing; this just means the FDA wants more safety studies done and not evidence that anything harmful actually happens. No problems were found and dermatologists still recommend using sunscreen.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.

This matters a lot because a lot of actives (like vitamin C) needs a specific pH to work well and feel comfortable on skin.

Concentration use ranges from 0.1-1.0% depending on the formula.

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!