Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

Biore UV Aqua Rich Watery Essence SPF 50+ PA++++ Versus Paula's Choice Resist Skin Restoring Moisturizer With SPF 50

Biore UV Aqua Rich Watery Essence SPF 50+ PA++++ Versus Paula's Choice Resist Skin Restoring Moisturizer With SPF 50 This chemical sunscreen covers the full UV range and blocks ~98% of UVB at SPF 50. This barrier-repair moisturizer is formulated around Allanto

Biore UV Aqua Rich Watery Essence SPF 50+ PA++++ Versus Paula's Choice Resist Skin Restoring Moisturizer With SPF 50

This chemical sunscreen covers the full UV range and blocks ~98% of UVB at SPF 50.

This barrier-repair moisturizer is formulated around Allantoin and Niacinamide to strengthen the skin barrier and soften the look of wrinkles.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Alcohol

Ethylhexyl Methoxycinnamate

Ethylhexyl Triazone

Isopropyl Palmitate

Lauryl Methacrylate/Sodium Methacrylate Crosspolymer

Diethylamino Hydroxybenzoyl Hexyl Benzoate

Hydrogenated Polyisobutene

Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine

Dextrin Palmitate

Butylene Glycol

Xylitol

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Dimethicone

C12-15 Alkyl Benzoate

Glycerin

Glyceryl Stearate

Propanediol

Glyceryl Behenate

Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer

Cetearyl Alcohol

Agar

Sorbitan Distearate

Isoceteth-20

Polyvinyl Alcohol

Dimethicone/Vinyl Dimethicone Crosspolymer

Stearoyl Glutamic Acid

Arginine

Potassium Hydroxide

Sodium Hydroxide

Royal Jelly Extract

Sodium Hyaluronate

Phenoxyethanol

Disodium EDTA

BHT

Parfum

Water, Alcohol, Ethylhexyl Methoxycinnamate, Ethylhexyl Triazone, Isopropyl Palmitate, Lauryl Methacrylate/Sodium Methacrylate Crosspolymer, Diethylamino Hydroxybenzoyl Hexyl Benzoate, Hydrogenated Polyisobutene, Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine, Dextrin Palmitate, Butylene Glycol, Xylitol, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Dimethicone, C12-15 Alkyl Benzoate, Glycerin, Glyceryl Stearate, Propanediol, Glyceryl Behenate, Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer, Cetearyl Alcohol, Agar, Sorbitan Distearate, Isoceteth-20, Polyvinyl Alcohol, Dimethicone/Vinyl Dimethicone Crosspolymer, Stearoyl Glutamic Acid, Arginine, Potassium Hydroxide, Sodium Hydroxide, Royal Jelly Extract, Sodium Hyaluronate, Phenoxyethanol, Disodium EDTA, BHT, Parfum

Butyl Methoxydibenzoylmethane 3%

Homosalate 5%

Ethylhexyl Methoxycinnamate 7.5%

Ethylhexyl Salicylate 5%

Benzophenone-3

Silica

Pentylene Glycol

Potassium Cetyl Phosphate

Cyclopentasiloxane

Pyrus Malus Fruit Extract

Vp/Eicosene Copolymer

Butyrospermum Parkii Butter

Allantoin

Niacinamide

Tocopherol

Glycyrrhiza Glabra Root Extract

Aloe Barbadensis Leaf Juice

Atractylodes Macrocephala Root Powder

Avena Sativa Kernel Extract

Coffea Arabica Seed Extract

Portulaca Oleracea Extract

Mahonia Aquifolium Root Extract

Diethylhexyl Syringylidenemalonate

Sarcosine

Capryloyl Glycine

Maltooligosyl Glucoside

Cetearyl Glucoside

Dimethiconol

Hydrogenated Starch Hydrolysate

Hexylene Glycol

4-T-Butylcyclohexanol

PEG-100 Stearate

Xanthan Gum

Caprylyl Glycol

Ethylhexylglycerin

Butyl Methoxydibenzoylmethane 3%, Homosalate 5%, Ethylhexyl Methoxycinnamate 7.5%, Ethylhexyl Salicylate 5%, Benzophenone-3, Water, Silica, Glycerin, Cetearyl Alcohol, Dimethicone, Butylene Glycol, Pentylene Glycol, Potassium Cetyl Phosphate, Cyclopentasiloxane, Pyrus Malus Fruit Extract, Vp/Eicosene Copolymer, Butyrospermum Parkii Butter, Allantoin, Niacinamide, Tocopherol, Glycyrrhiza Glabra Root Extract, Aloe Barbadensis Leaf Juice, Atractylodes Macrocephala Root Powder, Avena Sativa Kernel Extract, Coffea Arabica Seed Extract, Portulaca Oleracea Extract, Mahonia Aquifolium Root Extract, Diethylhexyl Syringylidenemalonate, Sarcosine, Capryloyl Glycine, Maltooligosyl Glucoside, Cetearyl Glucoside, Dimethiconol, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Hydrogenated Starch Hydrolysate, Hexylene Glycol, 4-T-Butylcyclohexanol, Glyceryl Stearate, PEG-100 Stearate, Sodium Hydroxide, Xanthan Gum, Disodium EDTA, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin

Reviews

Alternatives

Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

Acrylates/C10-30 Alkyl Acrylate Crosspolymer is a synthetic polymer. It is used to thicken, emulsify, and improve the texture of products.

As an emulsifier, it helps stabilize oil-in-water emulsions to give products an elegant feel when applied.

It can also form a thin protective film on skin. One study found that a formula using this polymer helped slow down how quickly other ingredients (like DEET) were absorbed through skin.

A 2024 study of over 1,300 patients confirmed that sensitization to this ingredient is rare. It is also non-mutagenic and has a clean track record.

Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

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.

Cetearyl alcohol is a waxy mixture of two fatty alcohols: cetyl alcohol and stearyl alcohol. It is an emollient and emulsifier.

Despite having "alcohol" in its name, it has nothing to do with drying solvent alcohols; the FDA also allows "alcohol-free" products to contain fatty alcohols like this ingredient.

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.

Dimethicone is a type of synthetic silicone created from natural materials such as quartz. It is also known as polydimethylsiloxane.

What it does:

Dimethicone comes in different viscosities:

Depending on the viscosity, dimethicone has different properties.

Ingredients lists don't always show which type is used, so we recommend reaching out to the brand if you have questions about the viscosity.

This ingredient is unlikely to cause irritation because it does not get absorbed into skin. However, people with silicone allergies should be careful about using this ingredient.

Note: Dimethicone may contribute to pilling. This is because it is not oil or water soluble, so pilling may occur when layered with products. When mixed with heavy oils in a formula, the outcome is also quite greasy.

Disodium EDTA is a chelating agent. It grabs onto and deactivates metal ions that sneak into your products from water, packaging, or air.

This ingredient mainly works behind the scenes and helps with:

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%.

This ingredient is also known as Octinoxate and is one of the oldest and most widely used chemical UV filters in skincare.

It has a simple job: soap up UVB radiation (290-320 nm), the wavelengths responsible for sunburn and a big chunk of long-term sun damage.

In formulas, it's always paired with a separate UVA filter because octinoxate solely protects skin from UVB.

Because it's an oil-soluble liquid, it's easy to blend into the oil phase of lotions/creams and gives a cosmetically elegant feel.

The one quirk about formulating this ingredient is photostability; the molecule slowly changes shape into a less effective version when sunlight hits it. So the longer you're in the sun, the weaker its protection gets. The drop can be more than 30% in some formulas.

It also doesn't play nice with Avobenzone (the common UVA filter) since avobenzone destabilizes octinoxate and the two degrade each other. But don't worry: brands have solved this issue by adding photostabilizers like Tinosorb S to prevent degradation and keep SPF stable under heavy UV exposure.

The maximum allowed level is 10% in the EU and Australia, 7.5% in the US and Canada, and 20% in Japan.

The Cosmetic Ingredient Review Panel has concluded this ingredient to be safe in cosmetics up to 10%.

One last thing worth knowing for context:

Octinoxate has been the subject of ongoing review in Europe where the Scientific Committee on Consumer Safety's (SCCS) 2025 final opinion is that this ingredient is an endocrine-active substance.

Lab and animal studies suggest it can act a bit like a hormone in the body (mildly mimicking estrogen and slightly blocking male hormones). It's important to know this hasn't really been shown to happen in everyday human use.

This ingredient is also banned in Hawaii over coral reef concerns.

Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.

Topically, glycerin does several things at once:

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.

Glyceryl Stearate is made by reacting glycerin with stearic acid (typically sourced from plant oils like palm or coconut). It's an emulsifier, emollient, and mild occlusive.

Emulsifiers help ingredients like oil and water stay mixed so your formula stays nicely blended and uniform in texture.

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.

Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).

It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.

On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.

Another perk of this ingredient is that it stays functional across a wide pH range (3-10).

You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.

Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.

Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.

Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.

Sodium Hydroxide is also known as lye or caustic soda. It is used to adjust the pH of products; many ingredients require a specific pH to be effective.

In small amounts, sodium hydroxide is considered safe to use. However, large amounts may cause chemical burns due to its high alkaline.

Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.

"Alkaline" refers to a high pH level. A low pH level would be considered acidic.

Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.

So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.

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!

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

Connected source records selected through this article’s public topic index.

01

Formula cabinet

Ingredients & structured notes

Ingredient index

Ingredients Explained

  1. 01These ingredients are found in both products.
  2. 02Ingredients higher up in an ingredient list are typically present in a larger amount.
  3. 03Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
  4. 04Topically, glycerin does several things at once:
  5. 05Your 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.
  6. 06Aquaporin-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.
  7. 07This 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.
  8. 08Just know very high concentrations (>40%) can feel tacky in low humidity.
  9. 09Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
  10. 10Glycolic Acid is arguably the most famous alpha hydroxy acid (AHA) with tons of research backing its benefits.
  11. 11It is found naturally in sugar cane but the form used in skincare is usually synthetic for purity and stability.
  12. 12Glycolic acid removes the top layer of dead skin cells to allow newer and fresher ones to emerge.
  13. 13AHAs work by breaking down the structural “glue” that holds old skin cells in place. When that buildup is gone, your skin can renew itself more efficiently.
  14. 14Research also shows glycolic acid stimulates collagen production, helping to firm and thicken the skin over time. This is one of its biggest advantages over other AHAs.
  15. 15Overall, glycolic acid helps with:
  16. 16Fun fact: Glycolic acid boosts skin hydration by helping it produce molecules that increase hyaluronic acid naturally.
  17. 17To work best, glycolic acid products should have a pH between 3-4 (that’s where exfoliation is most effective but still gentle on skin).
  18. 18The pH and concentration of a product are key to its effectiveness:
  19. 19It is normal to feel a slight stinging sensation when using glycolic acid. This usually fades as your skin adjusts.
  20. 20Because glycolic acid has the smallest molecular size in the AHA family, it can penetrate deeper, which enhances its effectiveness but also makes it more likely to irritate sensitive skin.
Source · skinsort.com
02

Product index

Related product references

03

Comparison edit

Read side by side