Skin science article
Peter Thomas Roth Potent C Brightening Vitamin C Moisturizer Versus Paula's Choice 25% Vitamin C + Glutathione Clinical Serum
Peter Thomas Roth Potent C Brightening Vitamin C Moisturizer Versus Paula's Choice 25% Vitamin C + Glutathione Clinical Serum This brightening moisturizer is formulated around Tetrahexyldecyl Ascorbate and Tocopheryl Acetate to brighten dull-looking skin and f
Peter Thomas Roth Potent C Brightening Vitamin C Moisturizer Versus Paula's Choice 25% Vitamin C + Glutathione Clinical Serum
This brightening moisturizer is formulated around Tetrahexyldecyl Ascorbate and Tocopheryl Acetate to brighten dull-looking skin and fade the look of dark spots.
This brightening serum is formulated around Tetrahexyldecyl Ascorbate and Ascorbyl Glucoside to brighten dull-looking skin and fade the look of dark spots.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Tetrahexyldecyl Ascorbate
Propanediol
C9-12 Alkane
Glycerin
Tocopheryl Acetate
Behenyl Alcohol
Palmitic Acid
Cetyl Palmitate
Polyglyceryl-2 Stearate
Stearic Acid
Stearyl Alcohol
Oleic Acid
Soy Acid
Ferulic Acid
Brassica Oleracea Acephala Leaf Extract
Olea Europaea Fruit Extract
Hydrolyzed Collagen
Elastin
Zingiber Officinale Root Extract
Lactic Acid
Ceramide NP
Sodium Hyaluronate
Butyrospermum Parkii Butter
Wheat Amino Acids
Glycine Soja Sterols
Saccharomyces Ferment
Jojoba Esters
Olus Oil
Glyceryl Stearate
Gluconolactone
Calcium Gluconate
Sodium Benzoate
Sodium PCA
Sodium Stearoyl Lactylate
Myristic Acid
Sodium Hydroxide
Sodium Lactate
Lauroyl Lysine
Arachidic Acid
Lauric Acid
Potassium Sorbate
Coco-Caprylate/Caprate
Sodium Carboxymethyl Beta-Glucan
Histidine Hcl
Carnosine
Polyglyceryl-6 Distearate
Arachidyl Alcohol
Cetyl Alcohol
Lauryl Alcohol
Xanthan Gum
Carbomer
Polyglyceryl-3 Beeswax
Ethylhexylglycerin
Disodium EDTA
Mica
Phenoxyethanol
CI 15985
CI 19140
Water, Tetrahexyldecyl Ascorbate, Propanediol, C9-12 Alkane, Glycerin, Tocopheryl Acetate, Behenyl Alcohol, Palmitic Acid, Cetyl Palmitate, Polyglyceryl-2 Stearate, Stearic Acid, Stearyl Alcohol, Oleic Acid, Soy Acid, Ferulic Acid, Brassica Oleracea Acephala Leaf Extract, Olea Europaea Fruit Extract, Hydrolyzed Collagen, Elastin, Zingiber Officinale Root Extract, Lactic Acid, Ceramide NP, Sodium Hyaluronate, Butyrospermum Parkii Butter, Wheat Amino Acids, Glycine Soja Sterols, Saccharomyces Ferment, Jojoba Esters, Olus Oil, Glyceryl Stearate, Gluconolactone, Calcium Gluconate, Sodium Benzoate, Sodium PCA, Sodium Stearoyl Lactylate, Myristic Acid, Sodium Hydroxide, Sodium Lactate, Lauroyl Lysine, Arachidic Acid, Lauric Acid, Potassium Sorbate, Coco-Caprylate/Caprate, Sodium Carboxymethyl Beta-Glucan, Histidine Hcl, Carnosine, Polyglyceryl-6 Distearate, Arachidyl Alcohol, Cetyl Alcohol, Lauryl Alcohol, Xanthan Gum, Carbomer, Polyglyceryl-3 Beeswax, Ethylhexylglycerin, Disodium EDTA, Mica, Phenoxyethanol, CI 15985, CI 19140
Dimethicone
Ascorbyl Glucoside
Silica
Pyrus Malus Fruit Extract
Hydrogenated Lecithin
Polyglyceryl-6 Polyricinoleate
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
Oryza Sativa Bran Extract
Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
Caprylyl Glycol
Lysine Carboxymethyl Cysteinate
Tocopherol
Glutathione
Sodium Citrate
Sodium Phytate
Hexylene Glycol
Helianthus Annuus Seed Extract
Urea
Mannitol
Caprylic/Capric Triglyceride
Rosmarinus Officinalis Leaf Extract
Polysorbate 60
Sorbitan Isostearate
Trehalose
Ascorbic Acid
Glucose
Vanilla Planifolia Fruit Extract
Polyquaternium-51
Ergothioneine
Triacetin
Water, Tetrahexyldecyl Ascorbate, Dimethicone, Glycerin, C9-12 Alkane, Ascorbyl Glucoside, Silica, Pyrus Malus Fruit Extract, Hydrogenated Lecithin, Polyglyceryl-6 Polyricinoleate, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Xanthan Gum, Oryza Sativa Bran Extract, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Cetyl Alcohol, Caprylyl Glycol, Lysine Carboxymethyl Cysteinate, Coco-Caprylate/Caprate, Tocopherol, Glutathione, Sodium Citrate, Sodium Phytate, Hexylene Glycol, Ethylhexylglycerin, Helianthus Annuus Seed Extract, Urea, Mannitol, Caprylic/Capric Triglyceride, Sodium PCA, Rosmarinus Officinalis Leaf Extract, Polysorbate 60, Sorbitan Isostearate, Trehalose, Ascorbic Acid, Glucose, Vanilla Planifolia Fruit Extract, Polyquaternium-51, Ergothioneine, Triacetin, Sodium Hyaluronate, Phenoxyethanol
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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.
C9-12 Alkane is synethically created using alkanes, or paraffins. It is added to products as a solvent. This means its main purpose is to help dissolve ingredients and create even texture.
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.
Coco-Caprylate/Caprate is a lightweight ester created from coconut oil fatty acids, caprylic acid, and capric acid.
It is an emollient that helps soften skin and reduce transepidermal water loss (TEWL). What sets it apart from heavier emollients is its ultralight, non-greasy feel.
Once applied, this ingredient dries down quickly and leaves a dry, silky finish behind. This also helps improve spreadability and texture.
This ingredient has an excellent safety-record and is non-irritating.
Typical concentrations for cosmetics range from 0.5-62%.
Research on Malassezia growth found no growth on fatty acid esters with chain lengths shorter than 12 carbons (it prefers C11-24).
Since Coco-Caprylate/Caprate is built on C8 and C10 fatty acids, it is out of the range that Malassezia metabolizes, and therefore safe for fungal acne.
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 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 PCA (the salt of PCA) is one of the most well-established humectants in skincare.
Why is it so special? Your skin already makes it naturally; it's a natural component of your skin's Natural Moisturizing Factor (NMF), or the mix of water-binding compounds inside your skin cells that keeps things soft and hydrated.
As a cosmetic ingredient, it grabs water and holds it in the upper layers of skin to smooth roughness and ease dehydration.
There's some clinical support for the NMF approach with a study showing that a cream built to mimic the skin's NMF significantly boosted hydration.
Safety-wise, this ingredient non-irritating, non-comedogenic, and non-phototoxic in testing, with minimal skin absorption.
It also works really well with other hydrators like glycerin or hyaluronic acid, and typical usage is somewhere between 0.2-4%.
Tetrahexyldecyl Ascorbate (THD) is a stable and oil-soluble form of Vitamin C.
THD is special in that it has the ability to travel deeper into skin than traditional ascorbic acid while maintaining the same skin benefits (double win!).
Because it’s oil-soluble, THD dives deep into your skin’s fatty layers (think ceramides and cholesterol) to fight off the kind of free radicals that mess with your skin barrier. This makes it a great pair with water-based vitamin C (ascorbic acid) that mainly works on the surface.
Even at just 0.1%, THD is already showing great antioxidant activity. When used up to 2%, it helps keep your skin happy and calm, especially when it’s stressed from pollution or sun.
Want to fade dark spots or tackle hyperpigmentation? You’ll want 5% or more. Pairing it with brightening buddies like niacinamide or licorice root gives even better results. One study even used 30% THD with other brighteners and saw real results on stubborn discoloration, even in melasma-prone skin.
A note on THD: It’s has a slightly silky, oily texture and usually shows up colorless or pale yellow (though the exact shade can vary by supplier).
While you can sneak it into water-based formulas, it really shines when paired with silicones or oils, which help your skin soak it up better.
THD is pretty stable, but it’s still vulnerable to degradation like ascorbic acid. Too much light or heat (above 113°F / 45°C) can break it down over time. Go for dark and opaque packaging that keeps it safe and shady!
Read more about other types of Vitamin C:
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.