Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

Paula's Choice Omega+ Complex Moisturizer Versus Kiehl's Ultra Facial Cream with Squalane

Paula's Choice Omega+ Complex Moisturizer Versus Kiehl's Ultra Facial Cream with Squalane This barrier-repair moisturizer is formulated around Butyrospermum Parkii Butter and Linoleic Acid to strengthen the skin barrier and hydrate skin. This barrier-repair mo

Paula's Choice Omega+ Complex Moisturizer Versus Kiehl's Ultra Facial Cream with Squalane

This barrier-repair moisturizer is formulated around Butyrospermum Parkii Butter and Linoleic Acid to strengthen the skin barrier and hydrate skin.

This barrier-repair moisturizer is formulated around Squalane and Pseudoalteromonas Ferment Extract to strengthen the skin barrier and hydrate skin.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Butyrospermum Parkii Butter

Ceteareth-6 Olivate

Butylene Glycol

C13-15 Alkane

Glycerin

Glyceryl Stearate

Polyglyceryl-4 Laurate

Decyl Oleate

Linum Usitatissimum Seed Oil

Salvia Hispanica Seed Oil

Olea Europaea Fruit Oil

Passiflora Edulis Seed Oil

Borago Officinalis Seed Oil

Hydrogenated Olive Oil

Psidium Guajava Fruit Extract

Olea Europaea Oil Unsaponifiables

Limnanthes Alba Seed Oil

Linoleic Acid

Linolenic Acid

Oleic Acid

Euterpe Oleracea Sterols

Ceramide AP

Ceramide EOP

Ceramide NP

Serine

Alanine

Glycine

Proline

Lysine Hcl

Threonine

Arginine

Squalane

Cholesterol

Phytosphingosine

Anastatica Hierochuntica Extract

Lecithin

Sodium Hyaluronate

Sodium Lactate

Boerhavia Diffusa Root Extract

Adenosine

Phytic Acid

Glutamic Acid

Betaine

Pullulan

PCA

Sodium PCA

Carbomer

Sodium Polyacrylate Starch

Sclerotium Gum

Xanthan Gum

Sodium Lauroyl Lactylate

Phenoxyethanol

Ethylhexylglycerin

Water, Butyrospermum Parkii Butter, Ceteareth-6 Olivate, Butylene Glycol, C13-15 Alkane, Glycerin, Glyceryl Stearate, Polyglyceryl-4 Laurate, Decyl Oleate, Linum Usitatissimum Seed Oil, Salvia Hispanica Seed Oil, Olea Europaea Fruit Oil, Passiflora Edulis Seed Oil, Borago Officinalis Seed Oil, Hydrogenated Olive Oil, Psidium Guajava Fruit Extract, Olea Europaea Oil Unsaponifiables, Limnanthes Alba Seed Oil, Linoleic Acid, Linolenic Acid, Oleic Acid, Euterpe Oleracea Sterols, Ceramide AP, Ceramide EOP, Ceramide NP, Serine, Alanine, Glycine, Proline, Lysine Hcl, Threonine, Arginine, Squalane, Cholesterol, Phytosphingosine, Anastatica Hierochuntica Extract, Lecithin, Sodium Hyaluronate, Sodium Lactate, Boerhavia Diffusa Root Extract, Adenosine, Phytic Acid, Glutamic Acid, Betaine, Pullulan, PCA, Sodium PCA, Carbomer, Sodium Polyacrylate Starch, Sclerotium Gum, Xanthan Gum, Sodium Lauroyl Lactylate, Phenoxyethanol, Ethylhexylglycerin

Dimethicone

Bis-PEG-18 Methyl Ether Dimethyl Silane

Sucrose Stearate

Stearyl Alcohol

PEG-8 Stearate

Myristyl Myristate

Prunus Armeniaca Kernel Oil

Persea Gratissima Oil

Cetyl Alcohol

Oryza Sativa Bran Oil

Chlorphenesin

Stearic Acid

Palmitic Acid

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Trisodium Ethylenediamine Disuccinate

Prunus Amygdalus Dulcis Oil

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

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.

Carbomer is a synthetic thickening and gelling agent. It's basically the ingredient that gives a lot of serums, gels, creams, and sunscreens their smooth, non-sticky texture.

Although legally permitted at very high levels, carbomers are normally used at concentrations below 1%.

It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.

Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.

A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.

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.

This ingredient is also known as olive oil. It has been used in skincare for centuries and science largely backs up its reputation as a nourishing emollient.

The main components of olive oil are oleic acid (55-83%), linoleic acid (3.5-20%), and palmitic acid (7-20%). Oleic acid promotes skin regeneration and helps regulate inflammatory responses.

Squalene is also naturally present in olive oil and exhibits moisturizing and antioxidant properties.

The polyphenols in olive oil also show anti-aging promise; one clinical study found a measurable improvement in skin appearance after 30 days of topical serum use.

Just be aware that applying olive oil directly to skin can weaken the barrier and cause redness. One study with volunteers found even people without sensitive skin experienced a significant reduction in stratum corneum integrity and induced mild erythema.

It's best to use this ingredient as part of a carefully crafted formula (instead of putting it on skin directly from the bottle).

Because it has a 2-3 on the comedogenic scale, it is a moderate risk for acne-prone skin. However, the overall formulation of a product matters more than a few ingredients with comedogenic ratings.

This ingredient may not be fungal acne safe because of the oleic and palmitic acid content. These fall within the C11-24 fatty acid range that the Malassezia yeast can metabolize to grow.

Overall, olive oil is a well-studied and nourishing skincare ingredient.

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.

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!

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.

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. 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. 06Carbomer is a synthetic thickening and gelling agent. It's basically the ingredient that gives a lot of serums, gels, creams, and sunscreens their smooth, non-sticky texture.
  7. 07Although legally permitted at very high levels, carbomers are normally used at concentrations below 1%.
  8. 08It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.
  9. 09Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.
  10. 10A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.
  11. 11Disodium EDTA is a chelating agent. It grabs onto and deactivates metal ions that sneak into your products from water, packaging, or air.
  12. 12This ingredient mainly works behind the scenes and helps with:
  13. 13On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.
  14. 14One 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 st…
  15. 15Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.
  16. 16You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.
  17. 17Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
  18. 18The 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 …
  19. 19Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.
  20. 20Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
Source · skinsort.com
02

Product index

Related product references

Product

Paula's Choice The Unscrub

Paula's Choice The Unscrub Paula's Choice The Unscrub ingredients explained: Aqua (Water), Jojoba Esters (Cleansing Beads), Caprylic/Capric Triglyceride (Skin-Replenishing), Glycerin (Skin …

Source: incidecoder.comView reference →
03

Comparison edit

Read side by side