IT Cosmetics Bye Bye Lines Anti-Aging Serum Versus Peter Thomas Roth Peptide 21 Wrinkle Resist Serum

IT Cosmetics Bye Bye Lines Anti-Aging Serum Versus Peter Thomas Roth Peptide 21 Wrinkle Resist Serum

This anti-aging serum is formulated around Ubiquinone and Niacinamide to soften the look of wrinkles.

This anti-aging serum is formulated around Tripeptide-10 Citrulline and Acetyl Octapeptide-3 to soften the look of wrinkles.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Cyclopentasiloxane

Cyclotetrasiloxane

Dimethicone

Isododecane

Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer

Glycerin

Dimethicone/Vinyl Dimethicone Crosspolymer

Hexyl Laurate

Cyclohexasiloxane

Ozokerite

PEG-10 Dimethicone

Petrolatum

Sodium Chloride

Caprylyl Methicone

Cetyl PEG/PPG-10/1 Dimethicone

Polyglyceryl-4 Isostearate

Polymethylsilsesquioxane

Polysilicone-11

Caprylyl Glycol

Ethylhexylglycerin

Sorbitan Olivate

1,2-Hexanediol

Butylene Glycol

Disodium EDTA

Propylene Glycol

Vitis Vinifera Seed Oil

Ubiquinone

Squalane

Simmondsia Chinensis Seed Oil

Sea Water

Punica Granatum Seed Oil

Persea Gratissima Oil

Orbignya Oleifera Seed Oil

Niacinamide

Mangifera Indica Seed Butter

Coffea Arabica Seed Extract

Citrus Aurantium Dulcis Oil

Citrus Grandis Peel Oil

Caffeine

Argania Spinosa Kernel Oil

Arbutin

Adenosine

Anthemis Nobilis Flower Water

Lactobacillus

Illite

Betula Platyphylla Japonica Juice

Perfluorohexane

Hibiscus Sabdariffa Flower Extract

Caviar Extract

Snail Secretion Filtrate

Olea Europaea Leaf Extract

Cucumis Sativus Fruit Extract

Camellia Sinensis Leaf Extract

Chrysanthemum Indicum Flower Extract

Cholesteryl Chloride

Cholesteryl Isostearate

Cholesteryl Nonanoate

Alcohol

Arnica Montana Flower Extract

Alchemilla Vulgaris Extract

Ananas Sativus Fruit Extract

Actinidia Chinensis Fruit Extract

Pueraria Lobata Root Extract

Perfluorodecalin

Morus Alba Fruit Extract

Magnolia Kobus Bark Extract

Glycine Soja Sprout Extract

Diospyros Kaki Leaf Extract

Cinnamomum Cassia Bark Extract

Artemisia Princeps Leaf Extract

Pentafluoropropane

Curcuma Longa Root Extract

Achillea Millefolium Extract

Steareth-20

Marrubium Vulgare Extract

Phenoxyethanol

Gentiana Lutea Root Extract

Artemisia Absinthium Extract

Hydrogenated Lecithin

Veronica Officinalis Extract

Primula Veris Extract

Mentha Piperita Leaf Extract

Melissa Officinalis Leaf Extract

Malva Sylvestris Extract

Hydrolyzed Hyaluronic Acid

Colloidal Oatmeal

Hydrolyzed Silk

Citric Acid

Potassium Sorbate

Sodium Benzoate

Algae Extract

Aloe Barbadensis Leaf Extract

N-Hydroxysuccinimide

Hydrolyzed Collagen

Caprylhydroxamic Acid

Tocopherol

Thiamine Hcl

Riboflavin

Retinyl Palmitate

Pantothenic Acid

Palmitoyl Oligopeptide

Niacin

Folic Acid

Chrysin

Carnitine Hcl

Biotin

Ascorbic Acid

Palmitoyl Tetrapeptide-7

Chlorhexidine Digluconate

CI 77891

Mica

Water, Cyclopentasiloxane, Cyclotetrasiloxane, Dimethicone, Isododecane, Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer, Glycerin, Dimethicone/Vinyl Dimethicone Crosspolymer, Hexyl Laurate, Cyclohexasiloxane, Ozokerite, PEG-10 Dimethicone, Petrolatum, Sodium Chloride, Caprylyl Methicone, Cetyl PEG/PPG-10/1 Dimethicone, Polyglyceryl-4 Isostearate, Polymethylsilsesquioxane, Polysilicone-11, Caprylyl Glycol, Ethylhexylglycerin, Sorbitan Olivate, 1,2-Hexanediol, Butylene Glycol, Disodium EDTA, Propylene Glycol, Vitis Vinifera Seed Oil, Ubiquinone, Squalane, Simmondsia Chinensis Seed Oil, Sea Water, Punica Granatum Seed Oil, Persea Gratissima Oil, Orbignya Oleifera Seed Oil, Niacinamide, Mangifera Indica Seed Butter, Coffea Arabica Seed Extract, Citrus Aurantium Dulcis Oil, Citrus Grandis Peel Oil, Caffeine, Argania Spinosa Kernel Oil, Arbutin, Adenosine, Anthemis Nobilis Flower Water, Lactobacillus, Illite, Betula Platyphylla Japonica Juice, Perfluorohexane, Hibiscus Sabdariffa Flower Extract, Caviar Extract, Snail Secretion Filtrate, Olea Europaea Leaf Extract, Cucumis Sativus Fruit Extract, Camellia Sinensis Leaf Extract, Chrysanthemum Indicum Flower Extract, Cholesteryl Chloride, Cholesteryl Isostearate, Cholesteryl Nonanoate, Alcohol, Arnica Montana Flower Extract, Alchemilla Vulgaris Extract, Ananas Sativus Fruit Extract, Actinidia Chinensis Fruit Extract, Pueraria Lobata Root Extract, Perfluorodecalin, Morus Alba Fruit Extract, Magnolia Kobus Bark Extract, Glycine Soja Sprout Extract, Diospyros Kaki Leaf Extract, Cinnamomum Cassia Bark Extract, Artemisia Princeps Leaf Extract, Pentafluoropropane, Curcuma Longa Root Extract, Achillea Millefolium Extract, Steareth-20, Marrubium Vulgare Extract, Phenoxyethanol, Gentiana Lutea Root Extract, Artemisia Absinthium Extract, Hydrogenated Lecithin, Veronica Officinalis Extract, Primula Veris Extract, Mentha Piperita Leaf Extract, Melissa Officinalis Leaf Extract, Malva Sylvestris Extract, Hydrolyzed Hyaluronic Acid, Colloidal Oatmeal, Hydrolyzed Silk, Citric Acid, Potassium Sorbate, Sodium Benzoate, Algae Extract, Aloe Barbadensis Leaf Extract, N-Hydroxysuccinimide, Hydrolyzed Collagen, Caprylhydroxamic Acid, Tocopherol, Thiamine Hcl, Riboflavin, Retinyl Palmitate, Pantothenic Acid, Palmitoyl Oligopeptide, Niacin, Folic Acid, Chrysin, Carnitine Hcl, Biotin, Ascorbic Acid, Palmitoyl Tetrapeptide-7, Chlorhexidine Digluconate, CI 77891, Mica

Rosa Centifolia Flower Water

Isopropyl Myristate

Mannitol

Natto Gum

Tripeptide-10 Citrulline

Acetyl Octapeptide-3

Palmitoyl Hexapeptide-12

Acetyl Tetrapeptide-11

Acetyl Hexapeptide-8

Acetyl Hexapeptide-1

Acetyl Tetrapeptide-9

Acetyl Tetrapeptide-2

Tripeptide-1

Hexapeptide-11

Dipeptide Diaminobutyroyl Benzylamide Diacetate

Palmitoyl Tripeptide-5

Trifluoroacetyl Tripeptide-2

Palmitoyl Tripeptide-1

Sodium Polyglutamate

Sodium Hyaluronate

Tocopheryl Acetate

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

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, 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

Alternatives

Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

Ascorbic Acid is is pure Vitamin C and is the biologically active form used directly by skin.

Not only is vitamin C great for your overall health and immune system, but it also has plenty of benefits for your skin. It is best supported by academic literature for:

Topical vitamin C has been shown to help neutralize oxidative stress from UV and pollution, helping to improve photoaging and hyperpigmentation when used consistently.

One clinical study found that using 5% topical vitamin C for six months improved signs of photodamaged skin, both on the surface and in the deeper structural layers of the skin.

While vitamin C doesn’t replace sunscreen, studies show it can boost photoprotection when combined with Vitamin E and ferulic acid. These two ingredients help improve stability and protective effects.

The big downside of this ingredient is formulation difficulty. Vitamin C is prone to oxidation and doesn't penetrate the skin unless formulated correctly. Research found that vitamin C absorbs into the skin best at a low pH (< 3.5) with about 20% being the upper limit for effective absorption.

Skin levels can saturate after repeated application; this means your skin won’t keep absorbing more once it’s full of vitamin C. This is why more isn’t always better with vitamin C and why very high concentrations don’t necessarily give extra benefits.

Ascorbic acid generally works well with many skincare ingredients but can be irritating when combined with other active ingredients. Strong oxidizing acne treatments like benzoyl peroxide can reduce the effectiveness of vitamin C if they are used at the same time; they are often recommended for use at different times of day.

Read more about other types of Vitamin C:

Foods rich with vitamin C include oranges, strawberries, broccoli, bell peppers, and more. When consuming Vitamin C, your skin receives a portion of the nutrients.

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).

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.

Palmitoyl Oligopeptide is a form of peptide. It is created by blending peptides with palmitic acid. Peptides are building blocks for protein.

This ingredients tells our body to create more collagen. Collagen is a protein that makes connective tissue. Boosting collagen production leads to a healthier skin barrier. Having a healthy skin barrier means having firm and hydrated skin.

Read more about other common types of peptides here:

Palmitoyl Tetrapeptide-7 (formerly Palmitoyl Tetrapeptide-3) is a synthetic peptide. Its main job is to fight what researchers call "inflammaging".

"Inflammaging" is the slow, low-grade chronic inflammation that quietly breaks down collagen as we age.

This ingredient calms down a specific inflammation signal in your skin cells (called IL-6). When left unchecked, this signal triggers enzymes that break down collagen and elastin.

Clinical testing showed statistically significant improvements in:

Studies also found the more of this ingredient used, the more your skin produces Collagen I, fibronectin, and hyaluronic acid.

You'll likely see this ingredient paired with Palmitoyl Tripeptide-1 in the well-known Matrixyl 3000 complex for enhanced anti-aging effects.

A 3% concentration applied twice daily for two months showed meaningful skin rejuvenation results in clinical panels.

Fungal acne note: Usually a palmitic acid component can feed Malassezia in unbound form, but here is is covalently bonded to the peptide. This means it is very difficult for Malassezia to access, and therefore very unlikely to cause fungal acne.

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.

Potassium 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.

Retinyl Palmitate is a form of retinoid. Retinoids are the superstar class of anti-aging ingredients that include Tretinoin and Retinol.

This particular ingredient has had a bumpy year with its rise and fall in popularity.

First, Retinyl Palmitate is created from Palmitic Acid and Retinol. It is a Retinol ester and considered one of the weaker forms of retinoid.

This is because all retinoids have to be converted to Tretinoin, AKA Retinoic Acid.

Retinyl Palmitate is pretty far down the line and has to go through multiple conversions before its effects are seen. Once it's on your skin, enzymes called esterases convert it into Retinol, then into Retinal, and finally into Retinoic Acid; that's three steps with a little lost at each one.

The benefits of Retinyl Palmitate are debated due to this long and ineffective conversion line.

So why use it at all?

The answer is stability. Retinol and Retinoic Acid break down fast when they hit light, heat, and air, and Retinoic Acid can be pretty irritating on top of that.

Retinyl Palmitate is much more stable and gentler, making it easier to formulate with and easier on sensitive skin (even if it's weaker gram for gram).

Studies show Retinyl Palmitate to help:

Newer research from 2023-2025 also found that Retinyl Palmitate works especially well when paired with Retinol. The two seem to cover each other's weak spots; retinol brings the potency while Retinyl Palmitate brings the stability and gentleness. Together, they repair UV damage better than either one does alone.

This ingredient used to be found in sunscreens to boost the efficacy of sunscreen filters.

The downfall of Retinyl Palmitate was due to released reports about the ingredient being correlated to sun damage and skin tumors.

Most of this traces back to a 2012 US National Toxicology Program (NTP) study where hairless mice coated in Retinyl Palmitate cream and exposed to UV light developed skin tumors faster.

Here's the nuance, though.

When the Cosmetic Ingredient Review (CIR) Expert Panel went back through that study, they found methodological flaws and decided the results couldn't be interpreted as proof of extra risk.

The EU's Scientific Committee on Consumer Safety (SCCS) said the mouse findings might point to a concern but they're hard to apply to humans since hairless mouse skin and human skin behave differently.

While there is a study showing this ingredient to cause DNA damage when exposed to UVA, there is no concrete proof of it being linked to skin cancer. It is completely safe to use when used correctly.

Both the CIR and the SCCS consider it safe at the concentrations used in cosmetics; the SCCS specifically cleared retinoids up to 0.05% in body lotions and 0.3% in face creams, hand creams, and rinse-off products.

As of 2025, the EU has written those limits into law, plus a label warning about your total Vitamin A intake from all sources.

All retinoids increase your skin's sensitivity to the sun in the first few months of usage. Be especially careful with reapplying sunscreen when using any form of retinoid.

One more note: if you're pregnant, high doses of Vitamin A can be a concern, so a lot of people skip topical retinoids (including Retinyl Palmitate) during pregnancy just to be safe. Check with your doctor if you're unsure.

Fun fact: This ingredient is often added to low-fat milk to increase the levels of Vitamin A.

Sodium 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.

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 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.

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!

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