Peter Thomas Roth Peptide 21 Wrinkle Resist Serum Versus Peter Thomas Roth PRO Strength Niacinamide Discoloration Treatment
This anti-aging serum is formulated around Tripeptide-10 Citrulline and Acetyl Octapeptide-3 to soften the look of wrinkles.
This brightening treatment is formulated around Niacinamide and Tranexamic Acid to fade the look of dark spots and brighten dull-looking skin.
What's inside
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Skin ConditioningGlycerin
HumectantRosa Centifolia Flower Water
Skin ConditioningIsopropyl Myristate
EmollientSqualane
EmollientMannitol
HumectantButylene Glycol
HumectantNatto Gum
Tripeptide-10 Citrulline
Skin ConditioningAcetyl Octapeptide-3
HumectantPalmitoyl Hexapeptide-12
Skin ConditioningAcetyl Tetrapeptide-11
Skin ConditioningAcetyl Hexapeptide-8
HumectantAcetyl Hexapeptide-1
Skin ConditioningPalmitoyl Oligopeptide
CleansingAcetyl Tetrapeptide-9
Skin ConditioningAcetyl Tetrapeptide-2
Skin ConditioningTripeptide-1
Skin ConditioningPalmitoyl Tetrapeptide-7
Skin ConditioningHexapeptide-11
Skin ConditioningDipeptide Diaminobutyroyl Benzylamide Diacetate
Skin ConditioningPalmitoyl Tripeptide-5
Skin ConditioningTrifluoroacetyl Tripeptide-2
Skin ConditioningPalmitoyl Tripeptide-1
Skin ConditioningSodium Polyglutamate
HumectantSodium Hyaluronate
HumectantTocopheryl Acetate
AntioxidantRetinyl Palmitate
Skin ConditioningAscorbic Acid
AntioxidantHydrolyzed Soy Protein
HumectantHydrolyzed Wheat Protein
Skin ConditioningLecithin
EmollientPseudoalteromonas Ferment Extract
HumectantAcrylates Copolymer
Magnesium Chloride
Polysorbate 20
EmulsifyingDimethyl Isosorbide
SolventAcrylates/C10-30 Alkyl Acrylate Crosspolymer
Emulsion StabilisingLeuconostoc/Radish Root Ferment Filtrate
AntimicrobialPEG-8 Dimethicone
EmulsifyingDisodium Phosphate
BufferingCarbomer
Emulsion StabilisingDextran
Sodium Lactate
BufferingTetradecyl Aminobutyroylvalylaminobutyric Urea Trifluoroacetate
Skin ConditioningXanthan Gum
EmulsifyingTriethanolamine
BufferingSodium Phosphate
BufferingOctyldodecanol
EmollientSilica
AbrasiveSodium Propoxyhydroxypropyl Thiosulfate Silica
Sodium Hydroxide
BufferingCaprylyl Glycol
EmollientPotassium Sorbate
PreservativeSodium Benzoate
MaskingPhenoxyethanol
PreservativeWater, Glycerin, Rosa Centifolia Flower Water, Isopropyl Myristate, Squalane, Mannitol, Butylene Glycol, Natto Gum, Tripeptide-10 Citrulline, Acetyl Octapeptide-3, Palmitoyl Hexapeptide-12, Acetyl Tetrapeptide-11, Acetyl Hexapeptide-8, Acetyl Hexapeptide-1, Palmitoyl Oligopeptide, Acetyl Tetrapeptide-9, Acetyl Tetrapeptide-2, Tripeptide-1, Palmitoyl Tetrapeptide-7, Hexapeptide-11, Dipeptide Diaminobutyroyl Benzylamide Diacetate, Palmitoyl Tripeptide-5, Trifluoroacetyl Tripeptide-2, Palmitoyl Tripeptide-1, Sodium Polyglutamate, Sodium Hyaluronate, Tocopheryl Acetate, Retinyl Palmitate, Ascorbic Acid, Hydrolyzed Soy Protein, Hydrolyzed Wheat Protein, Lecithin, Pseudoalteromonas Ferment Extract, Acrylates Copolymer, Magnesium Chloride, Polysorbate 20, Dimethyl Isosorbide, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Leuconostoc/Radish Root Ferment Filtrate, PEG-8 Dimethicone, Disodium Phosphate, Carbomer, Dextran, Sodium Lactate, Tetradecyl Aminobutyroylvalylaminobutyric Urea Trifluoroacetate, Xanthan Gum, Triethanolamine, Sodium Phosphate, Octyldodecanol, Silica, Sodium Propoxyhydroxypropyl Thiosulfate Silica, Sodium Hydroxide, Caprylyl Glycol, Potassium Sorbate, Sodium Benzoate, Phenoxyethanol
Water
Skin ConditioningNiacinamide
SmoothingIsononyl Isononanoate
EmollientDimethyl Isosorbide
SolventTranexamic Acid
AstringentDimethicone
EmollientPropanediol
SolventPentylene Glycol
Skin ConditioningCaprylic/Capric Triglyceride
MaskingAlpha-Arbutin
AntioxidantGlyceryl Stearate
EmollientC9-12 Alkane
SolventCetyl Alcohol
EmollientButyrospermum Parkii Butter
Skin ConditioningCitric Acid
BufferingKojic Acid
AntioxidantMorus Alba Root Extract
BleachingResveratrol
AntioxidantScutellaria Lateriflora Extract
Skin ConditioningHydrangea Arborescens Root Extract
Skin ConditioningSqualane
EmollientHydrolyzed Vegetable Protein
Skin ConditioningPhenoxyethanol
PreservativePEG-100 Stearate
SurfactantTocopheryl Acetate
AntioxidantPolyacrylate Crosspolymer-6
Emulsion StabilisingPEG-75 Stearate
SurfactantCeteareth-20
CleansingSteareth-20
CleansingSilica
AbrasiveAmmonium Acryloyldimethyltaurate/Beheneth-25 Methacrylate Crosspolymer
Emulsion StabilisingDimethiconol
EmollientCoco-Caprylate/Caprate
EmollientHydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
Emulsion StabilisingTitanium Dioxide
Cosmetic ColorantSodium Phytate
Diethylhexyl Syringylidenemalonate
Skin ProtectingPotassium Sorbate
PreservativeSodium Benzoate
MaskingPolysorbate 60
EmulsifyingPolysorbate 20
EmulsifyingT-Butyl Alcohol
PerfumingCaprylyl Glycol
EmollientHexylene Glycol
EmulsifyingSorbitan Isostearate
EmulsifyingWater, Niacinamide, Isononyl Isononanoate, Dimethyl Isosorbide, Tranexamic Acid, Dimethicone, Propanediol, Pentylene Glycol, Caprylic/Capric Triglyceride, Alpha-Arbutin, Glyceryl Stearate, C9-12 Alkane, Cetyl Alcohol, Butyrospermum Parkii Butter, Citric Acid, Kojic Acid, Morus Alba Root Extract, Resveratrol, Scutellaria Lateriflora Extract, Hydrangea Arborescens Root Extract, Squalane, Hydrolyzed Vegetable Protein, Phenoxyethanol, PEG-100 Stearate, Tocopheryl Acetate, Polyacrylate Crosspolymer-6, PEG-75 Stearate, Ceteareth-20, Steareth-20, Silica, Ammonium Acryloyldimethyltaurate/Beheneth-25 Methacrylate Crosspolymer, Dimethiconol, Coco-Caprylate/Caprate, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Titanium Dioxide, Sodium Phytate, Diethylhexyl Syringylidenemalonate, Potassium Sorbate, Sodium Benzoate, Polysorbate 60, Polysorbate 20, T-Butyl Alcohol, Caprylyl Glycol, Hexylene Glycol, Sorbitan Isostearate
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
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).
Learn more about Caprylyl GlycolDimethyl Isosorbide (often shortened to DMI) is a sugar-derived solvent made from sorbitol. It's used to dissolve tricky ingredients and help them mix smoothly into a formula.
Many actives sit as gritty crystals when undissolved, so DMI swoops in to full dissolve them. This helps improve texture, stability, and how evenly an active is distributed.
It does have a penetration-enhancing reputation that is a bit more nuanced than marketing suggests; a cell study on human skin found that 10% DMI didn't significantly boost the permeation of Hydroquinone, Salicylic Acid, or Octadecenedioic Acid compared to controls (though it did improve their solubility in the formula itself).
Typical usage concentrations usually range from 1-10% depending on the formula's needs; this ingredient is also well tolerated at these levels.
Learn more about Dimethyl IsosorbidePhenoxyethanol 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.
Learn more about PhenoxyethanolPolysorbate 20 is a gentle, water-soluble emulsifier and mild surfactant. It stops oil and water from separating to keep your formulas blended and stable.
It also acts as a mild penetration enhancer by helping active ingredients absorb slightly better.
The common safety discussion around this ingredient involves a manufacturing byproduct called 1,4-dioxane.
Trace amounts can form during production but the EU's Scientific Committee on Consumer Safety has concluded that levels at/below 10 ppm in finished products are safe (commercial products consistently fall within acceptable margins).
True allergic reactions are uncommon and the CIR Expert Panel has confirmed this ingredient to be safe as used in cosmetics.
Because it is derived from lauric acid, it may not be fungal acne safe.
Learn more about Polysorbate 20Potassium Sorbate is a preservative used to prevent yeast and mold in products. It is commonly found in both cosmetic and food products.
This ingredient comes from potassium salt derived from sorbic acid. Sorbic acid is a natural antibiotic and effective against fungus.
Both potassium sorbate and sorbic acid can be found in baked goods, cheeses, dried meats, dried fruit, ice cream, pickles, wine, yogurt, and more.
You'll often find this ingredient used with other preservatives.
Learn more about Potassium SorbateSilica, also known as silicon dioxide, is a naturally occurring mineral. It is used as a fine, spherical, and porous powder in cosmetics.
Though it has exfoliant properties, the function of silica varies depending on the product.
The unique structure of silica enhances the spreadability and adds smoothness, making it a great texture enhancer.
It is also used as an active carrier, emulsifier, and mattifier due to its ability to absorb excess oil.
In some products, tiny microneedles called spicules are made from silica or hydrolyzed sponge. When you rub them in, they lightly polish away dead skin layers and enhance the penetration of active ingredients.
Learn more about SilicaSodium Benzoate is a preservative. It's used in both cosmetic and food products to inhibit the growth of mold and bacteria. It is typically produced synthetically.
Both the US FDA and EU Health Committee have approved the use of sodium benzoate. In the US, levels of 0.1% (of the total product) are allowed.
Sodium benzoate works as a preservative by inhibiting the growth of bacteria inside of cells. It prevents the cell from fermenting a type of sugar using an enzyme called phosphofructokinase.
It is the salt of benzoic acid. Foods containing sodium benzoate include soda, salad dressings, condiments, fruit juices, wines, and snack foods.
Studies for using ascorbic acid and sodium benzoate in cosmetics are lacking, especially in skincare routines with multiple steps.
We always recommend speaking with a professional, such as a dermatologist, if you have any concerns.
Learn more about Sodium BenzoateSqualane 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.
Learn more about SqualaneTocopheryl Acetate is a stable, shelf-friendly form of vitamin E.
Formulators love it because plain vitamin E oxidizes quickly once it hits air. This acetate version stays stable and resists going off, helping to extend a product's shelf life.
It's actually inactive on its own and works like a slow-release "storage" form; the enzymes in your skin called esterases gradually convert it into active vitamin E over time.
One in vivo study showed 5% of the acetate in the living layer of the epidermis converted to vitamin E after 5 days of application. This study also found the skin gained protection against UV damage even though the conversion was slow and small.
Once converted, vitamin E acts as a skin's main fat-soluble antioxidant that fights free radicals to protect skin from damage.
Topical vitamin E generally boosts the skin's photoprotection, and it reduced UV-damage in animal models.
This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.
Overall, it has a pretty solid safety profile and has been found to be non-irritating and non-comedogenic. Allergic reactions may happen but stay rare due to how widely the ingredient gets used.
The concentration will vary depending on the formula; industry data shows 0.1% in baby lotions, 3% in lipsticks, and 5% in foot powders. You can also find this ingredient at 100% in a pure vitamin E oil.
Most leave-on skincare keeps it at the lower end, often between 0.5-1%.
Learn more about Tocopheryl AcetateWater. 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!
Learn more about Water