Skin science article
Kiehl's Micro-Dose Anti-Aging Retinol Serum with Ceramides and Peptide Versus Estée Lauder Advanced Night Repair Synchronized Recovery Complex II
Kiehl's Micro-Dose Anti-Aging Retinol Serum with Ceramides and Peptide Versus Estée Lauder Advanced Night Repair Synchronized Recovery Complex II This anti-aging serum is formulated around Niacinamide and Ceramide NP to soften the look of wrinkles and refine s
Kiehl's Micro-Dose Anti-Aging Retinol Serum with Ceramides and Peptide Versus Estée Lauder Advanced Night Repair Synchronized Recovery Complex II
This anti-aging serum is formulated around Niacinamide and Ceramide NP to soften the look of wrinkles and refine skin texture.
This barrier-repair serum is formulated around Bifida Ferment Lysate to strengthen the skin barrier.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Glycerin
Butylene Glycol
Pentylene Glycol
Niacinamide
Cetyl Alcohol
Isohexadecane
Isononyl Isononanoate
Diisopropyl Sebacate
2-Oleamido-1,3-Octadecanediol
4-T-Butylcyclohexanol
Acetyl Dipeptide-1 Cetyl Ester
Adenosine
Ceramide NP
Hydroxypalmitoyl Sphinganine
Lauroyl Lysine
Octyldodecanol
Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate
Sodium Chloride
Sodium Hyaluronate
Sodium Hydroxide
Trisodium Ethylenediamine Disuccinate
Retinol
Tocopherol
Dicaprylyl Ether
Ammonium Polyacryloyldimethyl Taurate
Behenyl Alcohol
Caprylyl Glycol
Carbomer
Cetearyl Alcohol
Cetearyl Glucoside
Glycine Soja Oil
Helianthus Annuus Seed Oil
Hydroxyethylcellulose
Lecithin
Phenethyl Alcohol
Poloxamer 188
Polycaprolactone
Sorbitan Laurate
Steareth-100
CI 40800
Chlorphenesin
Phenoxyethanol
Water, Glycerin, Butylene Glycol, Pentylene Glycol, Niacinamide, Cetyl Alcohol, Isohexadecane, Isononyl Isononanoate, Diisopropyl Sebacate, 2-Oleamido-1,3-Octadecanediol, 4-T-Butylcyclohexanol, Acetyl Dipeptide-1 Cetyl Ester, Adenosine, Ceramide NP, Hydroxypalmitoyl Sphinganine, Lauroyl Lysine, Octyldodecanol, Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate, Sodium Chloride, Sodium Hyaluronate, Sodium Hydroxide, Trisodium Ethylenediamine Disuccinate, Retinol, Tocopherol, Dicaprylyl Ether, Ammonium Polyacryloyldimethyl Taurate, Behenyl Alcohol, Caprylyl Glycol, Carbomer, Cetearyl Alcohol, Cetearyl Glucoside, Glycine Soja Oil, Helianthus Annuus Seed Oil, Hydroxyethylcellulose, Lecithin, Phenethyl Alcohol, Poloxamer 188, Polycaprolactone, Sorbitan Laurate, Steareth-100, CI 40800, Chlorphenesin, Phenoxyethanol
Bifida Ferment Lysate
Methyl Gluceth-20
PEG-75
Bis-PEG-18 Methyl Ether Dimethyl Silane
Propanediol
Cola Acuminata Seed Extract
Hydrolyzed Algin
Pantethine
Caffeine
Tripeptide-32
Ethylhexylglycerin
Sodium Rna
Bisabolol
Glycereth-26
Squalane
Oleth-3 Phosphate
Lactobacillus Ferment
Oleth-3
Oleth-5
Anthemis Nobilis Flower Extract
Faex Extract
Choleth-24
Hydrogenated Lecithin
Ceteth-24
Tocopheryl Acetate
Ethylhexyl Methoxycinnamate
Hexylene Glycol
Triethanolamine
Trisodium EDTA
BHT
Xanthan Gum
CI 14700
CI 19140
Water, Bifida Ferment Lysate, Methyl Gluceth-20, PEG-75, Bis-PEG-18 Methyl Ether Dimethyl Silane, Butylene Glycol, Propanediol, Cola Acuminata Seed Extract, Hydrolyzed Algin, Pantethine, Caffeine, Lecithin, Tripeptide-32, Ethylhexylglycerin, Sodium Rna, Bisabolol, Glycereth-26, Squalane, Sodium Hyaluronate, Oleth-3 Phosphate, Caprylyl Glycol, Lactobacillus Ferment, Oleth-3, Oleth-5, Anthemis Nobilis Flower Extract, Faex Extract, Choleth-24, Hydrogenated Lecithin, Ceteth-24, Tocopheryl Acetate, Ethylhexyl Methoxycinnamate, Hexylene Glycol, Carbomer, Triethanolamine, Trisodium EDTA, BHT, Xanthan Gum, Phenoxyethanol, CI 14700, CI 19140
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.
Caprylyl Glycol is a humectant, skin conditioner, emollient, and preservative booster derived from either caprylic acid or synthetically created.
Typical use levels vary from 0.3-1% as a preservative booster and go up to 2% to condition skin.
Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).
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.
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.
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 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.
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!