Skin science article
Kiehl's Ultra Facial Cream with Squalane Versus First Aid Beauty Hydrating Serum With Hyaluronic Acid
Kiehl's Ultra Facial Cream with Squalane Versus First Aid Beauty Hydrating Serum With Hyaluronic Acid This barrier-repair moisturizer is formulated around Squalane and Pseudoalteromonas Ferment Extract to strengthen the skin barrier and hydrate skin. This hydr
Kiehl's Ultra Facial Cream with Squalane Versus First Aid Beauty Hydrating Serum With Hyaluronic Acid
This barrier-repair moisturizer is formulated around Squalane and Pseudoalteromonas Ferment Extract to strengthen the skin barrier and hydrate skin.
This hydrating serum is formulated around Sodium Hyaluronate and Colloidal Oatmeal to hydrate skin and calm redness.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Glycerin
Dimethicone
Squalane
Bis-PEG-18 Methyl Ether Dimethyl Silane
Sucrose Stearate
Stearyl Alcohol
PEG-8 Stearate
Myristyl Myristate
Prunus Armeniaca Kernel Oil
Phenoxyethanol
Persea Gratissima Oil
Glyceryl Stearate
Cetyl Alcohol
Oryza Sativa Bran Oil
Olea Europaea Fruit Oil
Chlorphenesin
Stearic Acid
Palmitic Acid
Carbomer
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
Trisodium Ethylenediamine Disuccinate
Prunus Amygdalus Dulcis Oil
Xanthan Gum
Ethylhexylglycerin
Sodium Hydroxide
Tocopherol
Glycine Soja Oil
Pseudoalteromonas Ferment Extract
Myristic Acid
Hydroxypalmitoyl Sphinganine
Salicylic Acid
Helianthus Annuus Seed Oil
Rosmarinus Officinalis Leaf Extract
Citric Acid
Water, Glycerin, Dimethicone, Squalane, Bis-PEG-18 Methyl Ether Dimethyl Silane, Sucrose Stearate, Stearyl Alcohol, PEG-8 Stearate, Myristyl Myristate, Prunus Armeniaca Kernel Oil, Phenoxyethanol, Persea Gratissima Oil, Glyceryl Stearate, Cetyl Alcohol, Oryza Sativa Bran Oil, Olea Europaea Fruit Oil, Chlorphenesin, Stearic Acid, Palmitic Acid, Carbomer, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Trisodium Ethylenediamine Disuccinate, Prunus Amygdalus Dulcis Oil, Xanthan Gum, Ethylhexylglycerin, Sodium Hydroxide, Tocopherol, Glycine Soja Oil, Pseudoalteromonas Ferment Extract, Myristic Acid, Hydroxypalmitoyl Sphinganine, Salicylic Acid, Helianthus Annuus Seed Oil, Rosmarinus Officinalis Leaf Extract, Citric Acid
Glycereth-26
Sodium Hyaluronate
Soluble Collagen
Colloidal Oatmeal
Panthenol
Chrysanthemum Parthenium Extract
Camellia Sinensis Leaf Extract
Glycyrrhiza Glabra Root Extract
Allantoin
Sorbitan Oleate
Sodium PCA
Potassium Sorbate
Sodium Benzoate
Tetrasodium EDTA
Water, Glycerin, Glycereth-26, Squalane, Sodium Hyaluronate, Soluble Collagen, Colloidal Oatmeal, Panthenol, Chrysanthemum Parthenium Extract, Camellia Sinensis Leaf Extract, Glycyrrhiza Glabra Root Extract, Allantoin, Ethylhexylglycerin, Sorbitan Oleate, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Sodium PCA, Phenoxyethanol, Sodium Hydroxide, Potassium Sorbate, Sodium Benzoate, Tetrasodium EDTA
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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.
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.
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.
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.
Squalane is the hydrogenated and shelf-stable form of squalene (a lipid that naturally occurs in human sebum).
It is an emollient and skin conditioning agent that is able to integrate seamlessly into the skin's lipid barrier without clogging pores.
This is due to how structurally similar it is to what your skin already produces.
Though it is mostly an emollient that helps soften and hydrate skin, it also has some humectant and occlusive action. Humectants help the skin retain moisture while occlusives seal it in, making squalane a triple-threat moisturizer.
Research shows it has antioxidant capabilities that help protect against stressors like UV exposure, specifically UVA induced oxidative stress. This study also found that it supports collagen biosynthesis in human dermal fibroblasts.
No clinical study has reported significant adverse effects and irritation reactions are very rare from this ingredient (even at 100% concentration).
Overall, it's a fantastic ingredient for hydration and is suitable for all skin types.
This depends on the source. Squalane can be derived from both plants and animals. Most squalane used in skincare comes from plants.
Please note: the source of squalane is only known if disclosed by the brand. We recommend reaching out to the brand if you have any questions about their squalane.
Read more about squalene with an "e".
Though squalane is often called an oil, it’s technically not one. It is a hydrocarbon, meaning it is only made of carbon and hydrogen. True oils are triglycerides and made of fatty acids and glycerol.
The term “oil-free” isn’t regulated so companies can define it however they want. Some exclude all oils, while others just avoid mineral oil or comedogenic oils.
Squalane has a comedogenic rating of 1 from the original 1972 study that tested raw ingredients under occlusion on rabbit ears. This system is not standardized or peer-reviewed, and using the raw ingredients is very different from how diluted cosmetic formulations are used on human skin.
A comedogenic rating of 1 means it is "unlikely to clog pores" according to the original rating system.
The overall formula of a product matters more than the individual ingredients on whether or not it will cause clogged pores.
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!