Peptide Skincare & BeautySkin science and ingredient guides

Ingredient or product comparison

The INKEY List 1% Retinol Serum Versus Peter Thomas Roth Peptide 21 Wrinkle Resist Serum

The INKEY List 1% Retinol Serum Versus Peter Thomas Roth Peptide 21 Wrinkle Resist Serum Detailed comparison of The INKEY List 1% Retinol Serum versus Peter Thomas Roth Peptide 21 Wrinkle Resist Serum. This anti-aging serum is formulated around Retinol to soft

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The INKEY List 1% Retinol Serum Versus Peter Thomas Roth Peptide 21 Wrinkle Resist Serum Detailed comparison of The INKEY List 1% Retinol Serum versus Peter Thomas Roth Peptide 21 Wrinkle Resist Serum. This anti-aging serum is formulated around Retinol to soften the look of wrinkles and refine skin texture. This anti-aging serum is formulated around Tripeptide-10 Citrulline and Acetyl Octapeptide-3 to soften the look of wrinkles. Water Glycerin Prunus Armeniaca Kernel Oil Persea Gratissima Oil Caprylic/Capric Triglyceride Squalane Cetearyl Alcohol Glyceryl Stearate Se Retinol Phenoxyethanol Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer Benzyl Alcohol Phospholipids Tocopherol Polyacrylate Crosspolymer-6 Glycine Soja Oil Ethylhexylglycerin Glycolipids Dehydroacetic Acid Polysorbate 60 Sorbitan Isostearate Trisodium Ethylenediamine Disuccinate Glycine Soja Sterols T-Butyl Alcohol Water, Glycerin, Prunus Armeniaca Kernel Oil, Persea Gratissima Oil, Caprylic/Capric Triglyceride, Squalane, Cetearyl Alcohol, Glyceryl Stearate Se, Retinol, Phenoxyethanol, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Benzyl Alcohol, Phospholipids, Tocopherol, Polyacrylate Crosspolymer-6, Glycine Soja Oil, Ethylhexylglycerin, Glycolipids, Dehydroacetic Acid, Polysorbate 60, Sorbitan Isostearate, Trisodium Ethylenediamine Disuccinate, Glycine Soja Sterols, T-Butyl Alcohol Rosa Centifolia Flower Water Isopropyl Myristate 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 Water, 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, Car These ingredients are found in both products. Ingredients higher up in an ingredient list are typically present in a larger amount. 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. 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 sho