Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

Paula's Choice 1% Retinol Treatment Versus COSRX Real Fit Retinol Serum

Paula's Choice 1% Retinol Treatment Versus COSRX Real Fit Retinol Serum This anti-aging treatment is formulated around Retinol and Tetrahexyldecyl Ascorbate to soften the look of wrinkles and refine skin texture. This anti-aging serum is formulated around Cale

Paula's Choice 1% Retinol Treatment Versus COSRX Real Fit Retinol Serum

This anti-aging treatment is formulated around Retinol and Tetrahexyldecyl Ascorbate to soften the look of wrinkles and refine skin texture.

This anti-aging serum is formulated around Calendula Officinalis Extract and Retinyl Palmitate to soften the look of wrinkles and fade the look of dark spots.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Dimethicone

Glycerin

Butylene Glycol

Isononyl Isononanoate

Castor Isostearate Succinate

Glyceryl Stearate

C12-15 Alkyl Benzoate

Dimethicone Crosspolymer

PEG-33

Polysorbate 20

Behenyl Alcohol

PEG-100 Stearate

Pentaerythrityl Tetraisostearate

Polymethylsilsesquioxane

Tetrahexyldecyl Ascorbate

Retinol

Ceramide Ng

Palmitoyl Tetrapeptide-7

Palmitoyl Hexapeptide-12

Sodium Hyaluronate

Dipotassium Glycyrrhizate

Glycyrrhiza Glabra Root Extract

Avena Sativa Kernel Extract

Arctium Lappa Seed Oil

Salix Alba Extract

Glycine Soja Sterols

Lecithin

Allantoin

Tocopheryl Acetate

Hydrolyzed Soy Protein

Sorbitan Laurate

Acetyl Dipeptide-1 Cetyl Ester

Disodium EDTA

Hydroxyethylcellulose

Palmitoyl Tripeptide-1

Sodium Hydroxide

Tribehenin

Caprylyl Glycol

Ethylhexylglycerin

Pentylene Glycol

PEG-75 Shea Butter Glycerides

PPG-12/Smdi Copolymer

PEG-10 Phytosterol

PEG-8 Dimethicone

PEG-14

Magnesium Aluminum Silicate

Arachidyl Glucoside

Arachidyl Alcohol

Sclerotium Gum

Carbomer

Phenoxyethanol

Benzoic Acid

Water, Dimethicone, Glycerin, Butylene Glycol, Isononyl Isononanoate, Castor Isostearate Succinate, Glyceryl Stearate, C12-15 Alkyl Benzoate, Dimethicone Crosspolymer, PEG-33, Polysorbate 20, Behenyl Alcohol, PEG-100 Stearate, Pentaerythrityl Tetraisostearate, Polymethylsilsesquioxane, Tetrahexyldecyl Ascorbate, Retinol, Ceramide Ng, Palmitoyl Tetrapeptide-7, Palmitoyl Hexapeptide-12, Sodium Hyaluronate, Dipotassium Glycyrrhizate, Glycyrrhiza Glabra Root Extract, Avena Sativa Kernel Extract, Arctium Lappa Seed Oil, Salix Alba Extract, Glycine Soja Sterols, Lecithin, Allantoin, Tocopheryl Acetate, Hydrolyzed Soy Protein, Sorbitan Laurate, Acetyl Dipeptide-1 Cetyl Ester, Disodium EDTA, Hydroxyethylcellulose, Palmitoyl Tripeptide-1, Sodium Hydroxide, Tribehenin, Caprylyl Glycol, Ethylhexylglycerin, Pentylene Glycol, PEG-75 Shea Butter Glycerides, PPG-12/Smdi Copolymer, PEG-10 Phytosterol, PEG-8 Dimethicone, PEG-14, Magnesium Aluminum Silicate, Arachidyl Glucoside, Arachidyl Alcohol, Sclerotium Gum, Carbomer, Phenoxyethanol, Benzoic Acid

Calendula Officinalis Extract

Helianthus Annuus Seed Oil

1,2-Hexanediol

Polysorbate 60

Betaine

Cetearyl Alcohol

Retinyl Palmitate

Cetearyl Olivate

Panthenol

Arachis Hypogaea Oil

Sorbitan Olivate

Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer

Xanthan Gum

Juniperus Mexicana Oil

Adenosine

Tocopherol

Calendula Officinalis Extract, Butylene Glycol, Glycerin, Helianthus Annuus Seed Oil, 1,2-Hexanediol, Polysorbate 60, Betaine, Dimethicone, Cetearyl Alcohol, Retinyl Palmitate, Cetearyl Olivate, Panthenol, Arachis Hypogaea Oil, Sorbitan Olivate, Allantoin, Tocopheryl Acetate, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Hydroxyethylcellulose, Xanthan Gum, Juniperus Mexicana Oil, Ethylhexylglycerin, Adenosine, Tocopherol

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Alternatives

Ingredients Explained

These ingredients are found in both products.

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

Allantoin is a soothing ingredient known for its protective and moisturizing properties; it's basically a quiet workhorse ingredient you can find in a huge range of cosmetics.

Though it can be derived from the comfrey plant, allantoin is produced synthetically for cosmetic products to ensure purity.

Research shows it can encourage your skin cells to turn over and renew by stimulating keratinocyte and fibroblast proliferation.

It also has mild keratolytic properties to help loosen and shed dead skin cells without being harsh.

Studies also suggest allantoin can help calm inflammation by dialing down some of the chemical signals your skin sends out when it is irritated.

This ingredient is typically used in the 0.1-0.5% range, and the FDA recognizes it as a skin protectant in OTC products up to 2%.

Overall, allantoin is a wonderful addition to most routines; it is stable across a wide pH range (~4-8), works well with other ingredients, and is considered non-sensitizing/non-irritating.

Fun fact: Allantoin is naturally occurring in comfrey root, beets, chamomile, and wheat sprouts. Our bodies even produce it as a byproduct of uric acid metabolism.

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.

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.

Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:

The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.

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

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.

Hydroxyethylcellulose is used to improve the texture of products. It is created from a chemical reaction involving ethylene oxide and alkali-cellulose. Cellulose is a sugar found in plant cell walls and help give plants structure.

This ingredient helps stabilize products by preventing ingredients from separating. It can also help thicken the texture of a product.

This ingredient can also be found in pill medicines to help our bodies digest other ingredients.

Tocopheryl Acetate is a stable, shelf-friendly form of vitamin E.

Formulators love it because plain vitamin E oxidizes quickly once it hits air. This acetate version stays stable and resists going off, helping to extend a product's shelf life.

It's actually inactive on its own and works like a slow-release "storage" form; the enzymes in your skin called esterases gradually convert it into active vitamin E over time.

One in vivo study showed 5% of the acetate in the living layer of the epidermis converted to vitamin E after 5 days of application. This study also found the skin gained protection against UV damage even though the conversion was slow and small.

Once converted, vitamin E acts as a skin's main fat-soluble antioxidant that fights free radicals to protect skin from damage.

Topical vitamin E generally boosts the skin's photoprotection, and it reduced UV-damage in animal models.

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.

Overall, it has a pretty solid safety profile and has been found to be non-irritating and non-comedogenic. Allergic reactions may happen but stay rare due to how widely the ingredient gets used.

The concentration will vary depending on the formula; industry data shows 0.1% in baby lotions, 3% in lipsticks, and 5% in foot powders. You can also find this ingredient at 100% in a pure vitamin E oil.

Most leave-on skincare keeps it at the lower end, often between 0.5-1%.

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

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

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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. 03Caprylic/Capric Triglyceride (aka MCT Oil) is a lightweight emollient, solvent, and texture enhancer. It is considered a skin-softener by helping to prevent moisture loss.
  4. 04Though it behaves like an oil, it is not technically one due to its chemical composition. One perk of this ingredient is that it is very stable, resistant to oxidation, and unlikely to go rancid.
  5. 05In practice, that translates to a long shelf life and a consistently elegant skin feel.
  6. 06While there is an assumption Caprylic Triglyceride can clog pores due to it being derived from coconut oil, there is no research supporting this. Just patch test if you have concerns.
  7. 07Fractionated coconut oil and MCT Oil are both listed as Caprylic/Capric Triglyceride according to INCI. This is because INCI names are based on the ingredient’s final chemical composition and not its marketing name or source.
  8. 08This ingredient is treated as the gold standard fungal acne safe oil. Even though it is coconut derived, the problematic lauric acid is stripped out.
  9. 09This leaves just caprylic (C8) and capric (C10) acid. These chain lengths actually trend antifungal; a 2020 study found caprylic acid was enough to disrupt Malassezia furfur cell membrane, with a caprylic acid derivative damaging membrane structures…
  10. 10Cetearyl alcohol is a waxy mixture of two fatty alcohols: cetyl alcohol and stearyl alcohol. It is an emollient and emulsifier.
  11. 11Despite 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.
  12. 12It plays several roles in a formula:
  13. 13Typical 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.
  14. 14Multiple assessments have found it to be non-irritating and non-sensitizing to most people.
  15. 15However, there have been some cases of allergic contact dermatitis in patients with chronically compromised skin barriers.
  16. 16Cetearyl 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.
  17. 17Here'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.
  18. 18Remember 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.
  19. 19This ingredient is not fungal acne safe. Cetearyl alcohol is a fatty alcohol with chain lengths that fall within the range that Malassezia can metabolize.
  20. 20A 2019 study has also observed Malassezia growth in the presence of this ingredient, confirming it to be not-fungal acne safe.
Source · skinsort.com
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Product index

Related product references

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Comparison edit

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