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Skin science article

Paula's Choice Retinol Skin-Smoothing Body Treatment Versus CeraVe Skin Renewing Night Cream

Paula's Choice Retinol Skin-Smoothing Body Treatment Versus CeraVe Skin Renewing Night Cream This smoothing moisturizer is formulated around Retinol and Tetrahexyldecyl Ascorbate to refine skin texture and soften the look of wrinkles. This barrier-repair night

Paula's Choice Retinol Skin-Smoothing Body Treatment Versus CeraVe Skin Renewing Night Cream

This smoothing moisturizer is formulated around Retinol and Tetrahexyldecyl Ascorbate to refine skin texture and soften the look of wrinkles.

This barrier-repair night moisturizer is formulated around Ceramide NP 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

Cetearyl Alcohol

Cetearyl Ethylhexanoate

Cyclopentasiloxane

Dimethicone

Glycerin

Butylene Glycol

Cetyl Palmitate

Butyrospermum Parkii Butter

Glyceryl Stearate

PEG-100 Stearate

Oenothera Biennis Oil

Vitis Vinifera Seed Oil

Cetyl Alcohol

Retinol

Tetrahexyldecyl Ascorbate

Tocopheryl Acetate

Caprylic/Capric Triglyceride

Panthenol

Carnosine

Dimethiconol

Dimethicone/Vinyl Dimethicone Crosspolymer

Beeswax

Magnesium Aluminum Silicate

Sodium Hydroxide

Xanthan Gum

Dicaprylyl Carbonate

Decylene Glycol

Disodium EDTA

Chlorphenesin

Phenoxyethanol

Water, Cetearyl Alcohol, Cetearyl Ethylhexanoate, Cyclopentasiloxane, Dimethicone, Glycerin, Butylene Glycol, Cetyl Palmitate, Butyrospermum Parkii Butter, Glyceryl Stearate, PEG-100 Stearate, Oenothera Biennis Oil, Vitis Vinifera Seed Oil, Cetyl Alcohol, Retinol, Tetrahexyldecyl Ascorbate, Tocopheryl Acetate, Caprylic/Capric Triglyceride, Panthenol, Carnosine, Dimethiconol, Dimethicone/Vinyl Dimethicone Crosspolymer, Beeswax, Magnesium Aluminum Silicate, Sodium Hydroxide, Xanthan Gum, Dicaprylyl Carbonate, Decylene Glycol, Disodium EDTA, Chlorphenesin, Phenoxyethanol

Glyceryl Stearate Se

Saccharide Isomerate

Stearic Acid

Palmitic Acid

Glycine Soja Sterols

Allantoin

Ceramide NP

Ceramide AP

Ceramide EOP

Carbomer

Niacinamide

Behentrimonium Methosulfate

Myristic Acid

Sodium Lauroyl Lactylate

Sodium Benzoate

Sodium Citrate

Sodium Hyaluronate

Cholesterol

Tocopherol

Tripeptide-1

Laureth-9

Citric Acid

Caprooyl Tetrapeptide-3

Biosaccharide Gum-1

Phytosphingosine

Dextran

Ethylhexylglycerin

Water, Glycerin, Caprylic/Capric Triglyceride, Butyrospermum Parkii Butter, Dimethicone/Vinyl Dimethicone Crosspolymer, Cyclopentasiloxane, Glyceryl Stearate Se, Cetyl Alcohol, Dimethicone, Saccharide Isomerate, Stearic Acid, Palmitic Acid, Glycine Soja Sterols, Allantoin, Ceramide NP, Ceramide AP, Ceramide EOP, Carbomer, Niacinamide, Cetearyl Alcohol, Behentrimonium Methosulfate, Sodium Hydroxide, Myristic Acid, Sodium Lauroyl Lactylate, Sodium Benzoate, Sodium Citrate, Sodium Hyaluronate, Cholesterol, Phenoxyethanol, Tocopherol, Tripeptide-1, Laureth-9, Citric Acid, Caprooyl Tetrapeptide-3, Biosaccharide Gum-1, Phytosphingosine, Xanthan Gum, Dextran, Ethylhexylglycerin, Butylene Glycol

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.

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.

This ingredient is also known as shea butter. It is a plant-derived extract from the nuts of the Africa shea tree and one of the most well-studied emollients.

Because it has a high concentration of fatty acids (primarily oleic, stearic, and linoleic) it is able to form a protective barrier on the skin's surface. This helps seal in moisture and prevents transepidermal water loss (TEWL).

In vitro research found an increase in skin hydration by 58% and a decrease in TEWL by 37.8% after 24 hours of applying this ingredient (pretty impressive for a single ingredient!).

Besides hydration, shea butter also contains triterpenes that have anti-inflammatory potential. In particule, lupeol cinnamate has shown the highest anti-inflammatory activity in vivo.

Shea butter also contains vitamins A and E which may contribute to antioxidant activity.

While Shea Butter has an SPF rating of about 3-4, it is not a sunscreen replacement.

This ingredient may not be fungal acne safe because its fatty acids fall within the C11-C24 range that the Malassezia yeast can metabolize.

Caprylic/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.

Though 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.

In practice, that translates to a long shelf life and a consistently elegant skin feel.

While 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.

Fractionated 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.

This ingredient is treated as the gold standard fungal acne safe oil. Even though it is coconut derived, the problematic lauric acid is stripped out.

This 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 at concentrations as low as 0.2%.

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.

Cetyl Alcohol is a fatty alcohol. Fatty Alcohols are most often used as an emollient or to thicken a product.

Its main roles are:

Though it has "alcohol" in the name, it is not related to denatured alcohol or ethyl alcohol.

The FDA allows products labeled "alcohol-free" to have fatty alcohols.

This ingredient may not be fungal acne safe. It is a primary fatty alcohol with a chain length above 12 carbons. A study from 2019 show Malassezia can feed on fatty alcohols in this range, so it may trigger fungal acne in those prone to it.

Cyclopentasiloxane (D5) is a lightweight silicone that mostly acts as an emollient and solvent in cosmetics. Its the reason your products feel silky, fast-spreading, and non-greasy.

Since D5 is volatile, it does its thing and then evaporates off the skin quickly.

The safety profile of this ingredient is reassuring; the US CIR Expert Panel concluded D5 is safe as used in cosmetics and Health Canada concluded that D5 is not harmful to human health or the environment as currently used in cosmetics

There's a study that people mention about D5 in a rat study showing tumors. This study is related to long-term inhalation of high D5 levels.

Regulatory bodies have judged this study to be not applicable in topical skincare since skin absorption of D5 is very low and we're not really inhaling huge amounts of D5.

The only restriction for this ingredient is environmental. The European Chemicals Agency (ECHA) restricted D5 in wash-off cosmetics at or above 0.1% due to their persistence in water.

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.

This ingredient is a silicone elastomer that works as a texture enhancer, adds a silky slip, and also helps absorb excess oil.

Because it's a large macromolecule that's insoluble in water and chemically inert, it's not expected to penetrate or be absorbed into skin.

Human patch tests with a facial lotion containing 1% of this ingredient found no sensitization.

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.

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!

Xanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny.

On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multiple sugar molecules bonded together.

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.

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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. 03Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:
  4. 04Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.
  5. 05Though 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.
  6. 06Caprylyl Glycol is a humectant, skin conditioner, emollient, and preservative booster derived from either caprylic acid or synthetically created.
  7. 07Typical use levels vary from 0.3-1% as a preservative booster and go up to 2% to condition skin.
  8. 08Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).
  9. 09Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
  10. 10Topically, glycerin does several things at once:
  11. 11Your 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.
  12. 12Aquaporin-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.
  13. 13This 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.
  14. 14Just know very high concentrations (>40%) can feel tacky in low humidity.
  15. 15Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
  16. 16Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).
  17. 17It 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.
  18. 18On 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.
  19. 19Another perk of this ingredient is that it stays functional across a wide pH range (3-10).
  20. 20You'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.
Source · skinsort.com
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Product index

Related product references

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Comparison edit

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