Dot & Key Skincare Blueberry Hydrate 12% Barrier Repair Face Serum Versus COSRX The 6 Peptide Skin Booster Serum

Dot & Key Skincare Blueberry Hydrate 12% Barrier Repair Face Serum Versus COSRX The 6 Peptide Skin Booster Serum

This barrier-repair serum is formulated around Niacinamide and Ceramide NP to strengthen the skin barrier and hydrate skin.

This anti-aging serum is formulated around Niacinamide and Acetyl Hexapeptide-8 to soften the look of wrinkles and strengthen the skin barrier.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Niacinamide

Glycerin

Butylene Glycol

Xylitylglucoside

Anhydroxylitol

Xylitol

Cetyl Ethylhexanoate

Ethoxydiglycol

Propanediol

Phenyl Trimethicone

Cyclopentasiloxane

Dimethicone

Polysilicone-11

Decyl Glucoside

Helianthus Annuus Seed Oil

Methylsilanol Mannuronate

Squalane

Cetearyl Olivate

Sorbitan Olivate

Polyacrylate Crosspolymer-6

Betaine

Sodium PCA

Sodium Lactate

PCA

Serine

Alanine

Glycine

Glutamic Acid

Lysine Hcl

Threonine

Arginine

Proline

Alpha-Arbutin

Phytosteryl/Octyldodecyl Lauroyl Glutamate

Xanthan Gum

Allantoin

Ceramide EOP

Ceramide NP

Ceramide AP

Behenic Acid

Polyglyceryl-10 Stearate

Polyglyceryl-6 Behenate

Lactic Acid

Ectoin

Panthenol

Disodium EDTA

Sodium Hyaluronate

Tocopheryl Acetate

Carbomer

Polysorbate 20

Palmitoyl Tripeptide-1

Palmitoyl Tetrapeptide-7

Lactococcus Ferment Lysate

Vaccinium Uliginosum Berry Extract

Oryza Sativa Extract

Saccharomyces Ferment Lysate Filtrate

Citric Acid

Sodium Benzoate

Potassium Sorbate

Phenoxyethanol

Ethylhexylglycerin

Gardenia Florida Oil

Maltodextrin

Water, Niacinamide, Glycerin, Butylene Glycol, Xylitylglucoside, Anhydroxylitol, Xylitol, Cetyl Ethylhexanoate, Ethoxydiglycol, Propanediol, Phenyl Trimethicone, Cyclopentasiloxane, Dimethicone, Polysilicone-11, Decyl Glucoside, Helianthus Annuus Seed Oil, Methylsilanol Mannuronate, Squalane, Cetearyl Olivate, Sorbitan Olivate, Polyacrylate Crosspolymer-6, Betaine, Sodium PCA, Sodium Lactate, PCA, Serine, Alanine, Glycine, Glutamic Acid, Lysine Hcl, Threonine, Arginine, Proline, Alpha-Arbutin, Phytosteryl/Octyldodecyl Lauroyl Glutamate, Xanthan Gum, Allantoin, Ceramide EOP, Ceramide NP, Ceramide AP, Behenic Acid, Polyglyceryl-10 Stearate, Polyglyceryl-6 Behenate, Lactic Acid, Ectoin, Panthenol, Disodium EDTA, Sodium Hyaluronate, Tocopheryl Acetate, Carbomer, Polysorbate 20, Palmitoyl Tripeptide-1, Palmitoyl Tetrapeptide-7, Lactococcus Ferment Lysate, Vaccinium Uliginosum Berry Extract, Oryza Sativa Extract, Saccharomyces Ferment Lysate Filtrate, Citric Acid, Sodium Benzoate, Potassium Sorbate, Phenoxyethanol, Ethylhexylglycerin, Gardenia Florida Oil, Maltodextrin

Dipropylene Glycol

Pentylene Glycol

1,2-Hexanediol

Acetyl Hexapeptide-8

Copper Tripeptide-1

Sh-Polypeptide-121

Dipeptide Diaminobutyroyl Benzylamide Diacetate

Oligopeptide-68

Palmitoyl Tripeptide-8

Acetyl Glucosamine

Tocopherol

Dextran

Glycine Soja Oil

Hydrogenated Lecithin

Ammonium Acryloyldimethyltaurate/Vp Copolymer

Adenosine

Polyquaternium-51

Caprylyl Glycol

T-Butyl Alcohol

Sodium Oleate

Water, Dipropylene Glycol, Glycerin, Pentylene Glycol, 1,2-Hexanediol, Niacinamide, Acetyl Hexapeptide-8, Copper Tripeptide-1, Sh-Polypeptide-121, Dipeptide Diaminobutyroyl Benzylamide Diacetate, Oligopeptide-68, Palmitoyl Tripeptide-8, Allantoin, Sodium Hyaluronate, Acetyl Glucosamine, Serine, Alanine, Glycine, Threonine, Arginine, Proline, Betaine, Sodium PCA, Sodium Lactate, PCA, Glutamic Acid, Lysine Hcl, Tocopherol, Dextran, Glycine Soja Oil, Hydrogenated Lecithin, Ammonium Acryloyldimethyltaurate/Vp Copolymer, Polyacrylate Crosspolymer-6, Butylene Glycol, Xanthan Gum, Ethylhexylglycerin, Adenosine, Polyquaternium-51, Disodium EDTA, Citric Acid, Caprylyl Glycol, T-Butyl Alcohol, Potassium Sorbate, Sodium Oleate

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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.

Alanine is an amino acid and is already found in the human body. Our skin uses alanine to build collagen, elastin, and keratin.

Allantoin is a soothing ingredient known for its protective and moisturizing properties; it's basically a quiet workhorse ingredient you can find in a huge range of cosmetics.

Though it can be derived from the comfrey plant, allantoin is produced synthetically for cosmetic products to ensure purity.

Research shows it can encourage your skin cells to turn over and renew by stimulating keratinocyte and fibroblast proliferation.

It also has mild keratolytic properties to help loosen and shed dead skin cells without being harsh.

Studies also suggest allantoin can help calm inflammation by dialing down some of the chemical signals your skin sends out when it is irritated.

This ingredient is typically used in the 0.1-0.5% range, and the FDA recognizes it as a skin protectant in OTC products up to 2%.

Overall, allantoin is a wonderful addition to most routines; it is stable across a wide pH range (~4-8), works well with other ingredients, and is considered non-sensitizing/non-irritating.

Fun fact: Allantoin is naturally occurring in comfrey root, beets, chamomile, and wheat sprouts. Our bodies even produce it as a byproduct of uric acid metabolism.

Arginine is a semi-essential amino acid. This just means our bodies can product a bit on its own, but sometimes needs a little boost from food sources.

It is a part of your skin's natural moisturizing factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.

Here's an interesting thing about Arginine: your skin converts it into urea through the Krebs-Henseleit urea cycle. Urea is one of the most effective humectants your skin naturally produces.

A clinical study showed applying 2.5% arginine hydrochloride to atopic dermatitis skin showed significant urea levels in the stratum corneum and improved moisture in just four weeks.

Arginine is also a precursor to nitric oxide; nitric oxide improves microcirculation and supports wound healing and collagen synthesis.

One study found that an amino acid complex containing Arginine reduced skin irritation, improved hydration, and accelerated skin repair in clinical / in-vivo studies.

Arginine itself is an amino acid and not a fatty acid, oil, or ester. On its own, it's not a direct food source for Malassezia, or the yeast that causes fungal acne.

Betaine is a humectant. Like hyaluronic acid, it helps attract and retain moisture in the skin. It’s known for being gentle and for helping the skin maintain balanced hydration.

Betaine is mainly used to improve hydration and support calmer skin. It helps skin cells regulate water balance because it functions as an osmolyte.

Some studies suggest betaine may support making skin tone more even.

Fun fact: Betaine naturally exists in the skin and the body. In cosmetic products, it can be either plant-derived (most commonly from sugar beets) or synthetically produced for consistency and stability.

Betaine is also known as trimethylglycine.

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.

Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.

Like other AHAs, citric acid can exfoliate skin by breaking down the bonds that hold dead skin cells together. This helps reveal smoother and brighter skin underneath.

However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.

Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.

In skincare formulas, citric acid can:

While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.

Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.

Rosacea skin has a lower threshold for acids generally, with 62.5% of rosacea subjects in one study reacting to lactic acid in a sting test. This is why we mark citric acid as a potential rosacea trigger.

However, this ingredient shows up as a pH adjuster or chelator at roughly 0.1-1% in many products. These low levels are unlikely to be an issue for rosacea skin and becomes a potential trigger at exfoliating concentrations (20%). Because everybody's skin is unique, we recommend a patch test if you are unsure.

Disodium EDTA is a chelating agent. It grabs onto and deactivates metal ions that sneak into your products from water, packaging, or air.

This ingredient mainly works behind the scenes and helps with:

On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.

One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).

Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.

You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.

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.

Glutamic Acid is an amino acid that is found in all living organisms. Our bodies use this to help nerve cells in the brain communicate with other cells.

In cosmetics, glutamic acid is a famous humectant. It draws water from the air to your skin, keeping your skin hydrated (like hyaluronic acid).

An in-vitro study from 2024 found glutamic acid to play a role in inhibiting inflammation and thus a potential skin-soothing ingredient.

Other studies show it to be have potential wound healing, skin barrier repair, and hair growth properties.

Glutamic acid has poor solubility in water and other solvents.

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.

Glycine is the smallest amino acid and a key building block of collagen. It's part if your skin's Natural Moisturizing Factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.

A study from 2022 found that an amino acid complex featuring taurine, arginine, and glycine significantly reduced skin irritation, improved redness, and accelerated the skin repair process.

Lysine HCl is an alpha amino acid salt.

Our skin uses amino acids as a precursor for building protein, and therefore keratins, collagen and elastin.

Niacinamide is a multitasking form of vitamin B3 that strengthens the skin barrier, reduces pores and dark spots, regulates oil, and improves signs of aging.

And the best part? It's gentle and well-tolerated by most skin types, including sensitive and reactive skin.

You might have heard of "niacin flush", or the reddening of skin that causes itchiness. Niacinamide has not been found to cause this.

In very rare cases, some individuals may not be able to tolerate niacinamide at all or experience an allergic reaction to it.

If you are experiencing flaking, irritation, and dryness with this ingredient, be sure to double check all your products as this ingredient can be found in all categories of skincare.

When incorporating niacinamide into your routine, look out for concentration amounts. Typically, 5% niacinamide provides benefits such as fading dark spots. However, if you have sensitive skin, it is better to begin with a smaller concentration.

When you apply niacinamide to your skin, your body converts it into nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme that is already found in your cells as "fuel" and powers countless biological processes.

In your skin, NAD helps repair cell damage, produce new healthy cells, support collagen production, strengthen the skin barrier, and fight environmental stressors (like UV and pollution).

Our natural NAD levels start to decline with age, leading to slower skin repair, visible aging, and a weaker skin barrier. By providing your skin niacinamide, you're recharging your skin's NAD levels. This leads to stronger, healthier, and younger looking skin.

Another name for vitamin B3 is nicotinamide. This vitamin is water-soluble and our bodies don't store it. We obtain Vitamin B3 from either food or skincare. Meat, fish, wheat, yeast, and leafy greens contain vitamin B3.

The type of niacinamide used in skincare is synthetically created.

PCA is an amino acid derivative and one of the star players in your skin's own Natural Moisturizing Factor (NMF).

The NMF is the built-in cocktail of small molecules that keeps your outer layer of skin hydrated and your body makes it naturally.

This is why it works so well topically; PCA is a humectant that holds water in the stratum corneum and studies link higher skin PCA levels to better hydration + lower water loss. Interestingly, people show more PCA in summer and in normal vs dry skin.

Most of the benefits of this ingredient are related to hydration, softness, and barrier support.

A long-running review found that formulas with at least 2% PCA or its salts improved dry skin over both the short and long term. And the zinc salt is also used for its mild antimicrobial and astringent properties.

The salt forms are more common in cosmetics (like sodium PCA).

This ingredient is compatible with basically everything and pairs well with other humectants like glycerin or hyaluronic acid.

Usage-wise, it's typically used at low percentages (~0.2-2%).

The Cosmetic Ingredient Review Expert Panel has concluded PCA and its salts are safe as used and is non-irritating on skin even at high concentrations.

Polyacrylate Crosspolymer-6 is a texture enhancer and pH adjuster.

It is be used to thicken water-based products and create a gel-texture with a velvet feel.

One manufacturer claims this ingredient to have a pH range of 2-8 and to be biodegradable.

This ingredient is also known as Sepimax Zen.

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.

Proline is a non-essential amino acid, meaning your body can make it on its own. In skincare, it is a skin conditioning ingredient that keeps skin soft and hydrated.

It makes up about 23% of the collagen molecule (collagen is the protein responsible for keeping your skin firm) and is involved in your skin's natural hyaluronic acid production. When applied topically, proline can penetrate the skin fairly well due to its small molecular size.

Reviews of this ingredient have found it to be neither a dermal irritant nor a sensitizer.

Fun fact: Proline can be found in protein-rich foods like meat, fish, eggs, and dairy.

Serine is a non-essential amino acid (your body makes it on its own!). It is a major player in your skin's natural moisturizing factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.

Serine is one of your NMF's most abundant components that works as a skin-identical humectant. Its hydroxyl group grabs onto water molecules to boost hydration without any heaviness or occlusion.

Research on a hydrogel with serine confirmed this serine got delivered to your stratum corneum and demonstrated enhanced skin moisturization.

Interestingly serine also helps your skin produce filaggrin, a protein that keeps your skin barrier strong and used to create collagen.

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 Lactate is the sodium salt of lactic acid, an AHA. It is a humectant and sometimes used to adjust the pH of a product.

This ingredient is part of our skin's NMF, or natural moisturizing factor. Our NMF is essential for the hydration of our top skin layers and plasticity of skin. NMF also influences our skin's natural acid mantle and pH, which protects our skin from harmful bacteria.

High percentages of Sodium Lactate can have an exfoliating effect.

Fun fact: Sodium Lactate is produced from fermented sugar.

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%.

Threonine is an amino-acid. It helps hydrate the skin and has antioxidant benefits.

Our skin uses threonine for creating collagen and elastin. Humans are not able to create threonine and must get it through eating foods such as fish, lentils, poultry, sesame seeds, and more.

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.

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