Skin science article
Medik8 Crystal Retinal Ceramide Eye Versus Paula's Choice 1% Retinol Treatment
Medik8 Crystal Retinal Ceramide Eye Versus Paula's Choice 1% Retinol Treatment This anti-aging eye moisturizer is formulated around Retinal and Ceramide NP to soften the look of wrinkles and strengthen the skin barrier. This anti-aging treatment is formulated
Medik8 Crystal Retinal Ceramide Eye Versus Paula's Choice 1% Retinol Treatment
This anti-aging eye moisturizer is formulated around Retinal and Ceramide NP to soften the look of wrinkles and strengthen the skin barrier.
This anti-aging treatment is formulated around Retinol and Tetrahexyldecyl Ascorbate to soften the look of wrinkles and refine skin texture.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Caprylic/Capric Triglyceride
Butyrospermum Parkii Butter
Propanediol
Arachidyl Alcohol
Cetearyl Isononanoate
Glycerin
Isododecane
Squalane
Ethylhexyl Palmitate
Behenyl Alcohol
Cetearyl Alcohol
Glyceryl Stearate
Microcrystalline Cellulose
PPG-12/Smdi Copolymer
Tocopheryl Acetate
Phytosterols
Phenoxyethanol
Arachidyl Glucoside
Dimethicone
Sodium Acrylates Copolymer
Tocopherol
Linoleic Acid
Ceramide NP
Cyclodextrin
Bisabolol
Hydroxyacetophenone
Sodium Stearoyl Glutamate
Helianthus Annuus Seed Oil
Lecithin
Sodium Hyaluronate
Retinal
Pandanus Conoideus Fruit Oil
Daucus Carota Sativa Seed Oil
Lonicera Japonica Flower Extract
Lonicera Caprifolium Flower Extract
Sodium Polyaspartate
Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate
Disodium EDTA
Rubus Chamaemorus Seed Oil
Xanthan Gum
Ethylhexylglycerin
Cellulose
BHT
Sodium Hydroxide
Pentylene Glycol
Trihydroxystearin
Water, Caprylic/Capric Triglyceride, Butyrospermum Parkii Butter, Propanediol, Arachidyl Alcohol, Cetearyl Isononanoate, Glycerin, Isododecane, Squalane, Ethylhexyl Palmitate, Behenyl Alcohol, Cetearyl Alcohol, Glyceryl Stearate, Microcrystalline Cellulose, PPG-12/Smdi Copolymer, Tocopheryl Acetate, Phytosterols, Phenoxyethanol, Arachidyl Glucoside, Dimethicone, Sodium Acrylates Copolymer, Tocopherol, Linoleic Acid, Ceramide NP, Cyclodextrin, Bisabolol, Hydroxyacetophenone, Sodium Stearoyl Glutamate, Helianthus Annuus Seed Oil, Lecithin, Sodium Hyaluronate, Retinal, Pandanus Conoideus Fruit Oil, Daucus Carota Sativa Seed Oil, Lonicera Japonica Flower Extract, Lonicera Caprifolium Flower Extract, Sodium Polyaspartate, Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate, Disodium EDTA, Rubus Chamaemorus Seed Oil, Xanthan Gum, Ethylhexylglycerin, Cellulose, BHT, Sodium Hydroxide, Pentylene Glycol, Trihydroxystearin
Butylene Glycol
Isononyl Isononanoate
Castor Isostearate Succinate
C12-15 Alkyl Benzoate
Dimethicone Crosspolymer
PEG-33
Polysorbate 20
PEG-100 Stearate
Pentaerythrityl Tetraisostearate
Polymethylsilsesquioxane
Tetrahexyldecyl Ascorbate
Retinol
Ceramide Ng
Palmitoyl Tetrapeptide-7
Palmitoyl Hexapeptide-12
Dipotassium Glycyrrhizate
Glycyrrhiza Glabra Root Extract
Avena Sativa Kernel Extract
Arctium Lappa Seed Oil
Salix Alba Extract
Glycine Soja Sterols
Allantoin
Hydrolyzed Soy Protein
Sorbitan Laurate
Acetyl Dipeptide-1 Cetyl Ester
Hydroxyethylcellulose
Palmitoyl Tripeptide-1
Tribehenin
Caprylyl Glycol
PEG-75 Shea Butter Glycerides
PEG-10 Phytosterol
PEG-8 Dimethicone
PEG-14
Magnesium Aluminum Silicate
Sclerotium Gum
Carbomer
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
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.
Arachidyl Alcohol is a fatty alcohol made from the the arachidic acid found in peanut oil.
Despite having "alcohol" in the name, it is not related to denatured alcohol or ethanol.
This ingredient is a multitasker:
Just be sure to patch this ingredient if you have a peanut allergy (though this ingredient is highly processed and the allergenic proteins are typically removed).
This ingredient is a plant-based surfactant and emulsifier. It helps oil and water based ingredients mix evenly to improve formula stability without adding a "greasy" feel.
Behenyl Alcohol is a type of fatty alcohol (these are different from the drying, solvent alcohols).
Fatty Alcohols have hydrating properties and are most often used as an emollient or to thicken a product. They are usually derived from natural fats and oils; behenyl alcohol is derived from the fats of vegetable oils.
Emollients help keep your skin soft and hydrated by creating a film that traps moisture in.
In 2000, Behenyl Alcohol was approved by the US as medicine to reduce the duration of cold sores.
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%.
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.
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.
Lecithin is a term for a group of substances found in the cell membranes of plants, animals, and humans. They are made up of phospholipids.
Thanks to its amphiphilic structure (water-loving head and oil-loving tail), it is a true multitasker:
It plays well with most ingredients and is typically used at 0.1-1%. However, concentrations up to 50% have been reported in moisturizers.
Pentylene Glycol (1,2-pentanediol) is a multitasking little diol with three main roles in a formula:
Research on alkanediols (the family pentylene glycol belongs to) show they work by disrupting microbial cell membranes. This disruption helps the primary preservative system in a product work more effectively at lower doses.
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%.
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.
We don't have a description for PPG-12/Smdi Copolymer yet.
Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.
In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.
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.
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.
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%.
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!