Etude House Soon Jung Director's Moisture Sun Cream SPF50+ PA++++ Versus Suntique I'm Vegan Sun Serum SPF50+ PA++++

Another pro?

It's exceptionally photostable, barely degrades in sunlight, and acts as a "bodyguard" for less stable filters.

That's why you'll see it paired with avobenzone or octinoxate; this team up ensures they keep working through sun exposure.

Safety reviews have been reassuring across the board. This ingredient shows low absorption through the skin, rarely irritates, and lab studies found it doesn't act like a hormone in the body (a concern that's been raised about some older sunscreen filters).

On maximum concentrations:

In 2026, the US F.D.A finally added it as an OTC sunscreen ingredient at concentrations up to 6% for adults / children 6 months and older

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.

A high amount of carbomer can cause pilling or balling up of products. Don't worry, most products contain 1% or less of carbomer.

It plays several roles in a formula:

Typical use levels for this ingredient sit around 1-10% and the Cosmetic Ingredient Review Expert Panel has affirmed safety at concentrations up to 25% in leave-on products.

Multiple assessments have found it to be non-irritating and non-sensitizing to most people.

However, there have been some cases of allergic contact dermatitis in patients with chronically compromised skin barriers.

Cetearyl alcohol has a comedogenic rating of 2 and irritancy rating of 1. Both of these numbers come from the 1989 study that used rabbit ears; a "2" means mildly comedogenic and a "1" means low irritancy.

Here's the catch: rabbit skin is more sensitive than human skin and throws a lot of false positives. A 1996 reappraisal found that ingredients rated 1-2 in the rabbit ear tests are generally safe for humans.

Remember comedogenic ratings are unable to assess the entire formula of a product or how it will react on your skin. Just be sure to patch test if you are unsure about certain ingredients.

This ingredient is not fungal acne safe. Cetearyl alcohol is a fatty alcohol with chain lengths that fall within the range that Malassezia can metabolize.

A 2019 study has also observed Malassezia growth in the presence of this ingredient, confirming it to be not-fungal acne safe.

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.

DHHB has been approved by the EU, Japan, Taiwan, and South America for use up to 10%. Unfortunately, it has not been approved for use in the US or Canada due to slow regulatory processes.

This ingredient is soluble in oils, fats, and lipids.

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%.

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.

This ingredient is typically used in concentrations between 1-10%. Studies have found it to be non-sensitizing, non-phototoxic, and non-photoallergenic.

A close cousin of this ingredient is Glyceryl Stearate SE ("self-emulsifying"). This just has a small amount of sodium or potassium stearate added so it can emulsify without a co-emulsifier.

Since this ingredient is an ester of a C18 fatty acid, it may not be fungal acne safe. The Malassezia yeast can potentially metabolize within the C11-C24 range.

Fun fact: The human body also creates Glyceryl Stearate naturally.

Emulsifiers help stabilize a product. It does this by preventing certain ingredients from separating. Common ingredients include oils and water, which do not mix naturally. Emulsifiers have properties that help keep ingredients such as these together.

Emollients help soothe and soften the skin. They do this by creating a protective film on your skin. This barrier helps trap moisture and keeps your skin hydrated. Emollients may be effective at treating dry or itchy skin.

Surfactants help gather oils, dirt, and other pollutants from the skin. This helps them to be easily rinsed away.

This property also makes Pentylene Glycol a great texture enhancer. It can also help thicken or stabilize a product.

Pentylene Glycol also acts as a mild preservative and helps to keep a product microbe-free.

Some people may experience mild eye and skin irritation from Pentylene Glycol. We always recommend speaking with a professional about using this ingredient in your routine.

Pentylene Glycol has a low molecular weight and is part of the 1,2-glycol family.

This ingredient is not water-soluble.

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.

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.

Tromethamine helps balance the pH level of a product. Normal pH level of skin is slightly acidic (~4.75-5.5). The acidity of our skin is maintained by our glands and skin biome. Being slightly acidic allows our skin to create an "acid mantle". This acid mantle is a thin barrier that protects our skin from bacteria and contaminants.

Oral Tromethanmine is an anti-inflammatory drug but plays the role of masking, adding fragrance, and/or balancing pH in skincare.

1,3-Propanediol, 2-amino-2-(hydroxymethyl)-

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!