Skin science article
Peter Thomas Roth Potent-C Power Serum Versus Paula's Choice C15 Super Booster
Peter Thomas Roth Potent-C Power Serum Versus Paula's Choice C15 Super Booster This brightening serum is formulated around Tetrahexyldecyl Ascorbate and Tocopheryl Acetate to brighten dull-looking skin and soften the look of wrinkles. This brightening serum is
Peter Thomas Roth Potent-C Power Serum Versus Paula's Choice C15 Super Booster
This brightening serum is formulated around Tetrahexyldecyl Ascorbate and Tocopheryl Acetate to brighten dull-looking skin and soften the look of wrinkles.
This brightening serum is formulated around Ascorbic Acid and Ferulic Acid to brighten dull-looking skin and soften the look of wrinkles.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Tetrahexyldecyl Ascorbate
Butylene Glycol
C9-12 Alkane
Caprylyl Methicone
Tocopheryl Acetate
C10-18 Triglycerides
Polyglyceryl-6 Distearate
Ferulic Acid
Squalane
Hydrogenated Lecithin
Propanediol
Sodium Hyaluronate
Zingiber Officinale Root Extract
Curcuma Longa Root Extract
Panax Ginseng Root Extract
Jojoba Esters
Leuconostoc/Radish Root Ferment Filtrate
Coco-Caprylate/Caprate
Glycerin
Cetyl Alcohol
Polyglyceryl-3 Beeswax
Xanthan Gum
Disodium EDTA
Mica
Ethylhexylglycerin
Potassium Sorbate
Sodium Benzoate
Phenoxyethanol
Water, Tetrahexyldecyl Ascorbate, Butylene Glycol, C9-12 Alkane, Caprylyl Methicone, Tocopheryl Acetate, C10-18 Triglycerides, Polyglyceryl-6 Distearate, Ferulic Acid, Squalane, Hydrogenated Lecithin, Propanediol, Sodium Hyaluronate, Zingiber Officinale Root Extract, Curcuma Longa Root Extract, Panax Ginseng Root Extract, Jojoba Esters, Leuconostoc/Radish Root Ferment Filtrate, Coco-Caprylate/Caprate, Glycerin, Cetyl Alcohol, Polyglyceryl-3 Beeswax, Xanthan Gum, Disodium EDTA, Mica, Ethylhexylglycerin, Potassium Sorbate, Sodium Benzoate, Phenoxyethanol
Ascorbic Acid
Dipropylene Glycol
Ethoxydiglycol
Sodium Hydroxide
PPG-26-Buteth-26
PEG-40 Hydrogenated Castor Oil
Bisabolol
Sodium Phytate
Decylene Glycol
Tocopherol
1,2-Hexanediol
Sphingomonas Ferment Extract
Water, Ascorbic Acid, Dipropylene Glycol, Propanediol, Glycerin, Ethoxydiglycol, Sodium Hydroxide, PPG-26-Buteth-26, PEG-40 Hydrogenated Castor Oil, Bisabolol, Ferulic Acid, Sodium Phytate, Decylene Glycol, Tocopherol, 1,2-Hexanediol, Sphingomonas Ferment Extract, 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.
Ferulic Acid is a plant based antioxidant that can be naturally found in the cell walls of grains like rice, oats, and corn. It has antioxidant and antimicrobial properties, and has the ability to boost the performance of other antioxidants as well.
A well-known study found that adding Ferulic Acid to a solution of Vitamins C and E doubled the photoprotection of skin. This is why you'll often see it paired with Vitamin C or Vitamin E serums rather than sold on its own.
A 2025 review of 18 human studies found that using Ferulic Acid (0.5-1%) daily for one to three months showed improvements in:
As far as allergies go, Ferulic acid is generally well-tolerated but can cause an allergic reaction in very rare cases. It's also worth noting that Ferulic acid is often extracted from plant sources like rice bran or wheat bran, so be sure to path test if you have known grain allergies.
Outside of skincare, researchers are also looking into Ferulic Acid for its potential benefits in areas like diabetes, Alzheimer's, and heart health.
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.
Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.
It’s often used to:
Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.
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!