Paula's Choice Peptide Booster Versus Carrot & Stick The Repair Serum

Paula's Choice Peptide Booster Versus Carrot & Stick The Repair Serum

This anti-aging treatment is formulated around Tripeptide-1 and Palmitoyl Tripeptide-1 to soften the look of wrinkles and refine skin texture.

This barrier-repair serum is formulated around Niacinamide and Sh-Oligopeptide-1 to strengthen the skin barrier and soften the look of wrinkles.

What's inside

Key Ingredients

Benefits

Concerns

No concerns

Ingredients Side-by-side

Water

Glycerin

PEG-8 Dimethicone

Tripeptide-1

Palmitoyl Tripeptide-1

Palmitoyl Tetrapeptide-7

Palmitoyl Hexapeptide-12

Myristoyl Hexapeptide-16

Myristoyl Pentapeptide-17

Hexanoyl Dipeptide-3 Norleucine Acetate

Azelaoyl Bis-Dipeptide-10

Glycoproteins

Phospholipids

Adenosine

Dipotassium Glycyrrhizate

Arginine

Valine

Glycine

Alanine

Glutamic Acid

Serine

Threonine

Yeast Extract

Isoleucine

Proline

Histidine

Phenylalanine

PCA

Phytic Acid

Panax Ginseng Root Extract

Sodium PCA

Psidium Guajava Fruit Extract

Euterpe Oleracea Fruit Extract

Ahnfeltiopsis Concinna Extract

Dextran

Hydrolyzed Silk

Lecithin

Glyceryl Polymethacrylate

C12-16 Pareth-9

Trideceth-12

Sodium Lactate

Carbomer

Aspartic Acid

Polysorbate 20

Butylene Glycol

Caprylyl Glycol

PEG-8

C11-15 Pareth-7

Guar Hydroxypropyltrimonium Chloride

Phytosteryl/Octyldodecyl Lauroyl Glutamate

Ectoin

Citrate Buffer

Trimethylsiloxyamodimethicone

Phenoxyethanol

Sodium Hydroxide

Ethylhexylglycerin

Water, Glycerin, PEG-8 Dimethicone, Tripeptide-1, Palmitoyl Tripeptide-1, Palmitoyl Tetrapeptide-7, Palmitoyl Hexapeptide-12, Myristoyl Hexapeptide-16, Myristoyl Pentapeptide-17, Hexanoyl Dipeptide-3 Norleucine Acetate, Azelaoyl Bis-Dipeptide-10, Glycoproteins, Phospholipids, Adenosine, Dipotassium Glycyrrhizate, Arginine, Valine, Glycine, Alanine, Glutamic Acid, Serine, Threonine, Yeast Extract, Isoleucine, Proline, Histidine, Phenylalanine, PCA, Phytic Acid, Panax Ginseng Root Extract, Sodium PCA, Psidium Guajava Fruit Extract, Euterpe Oleracea Fruit Extract, Ahnfeltiopsis Concinna Extract, Dextran, Hydrolyzed Silk, Lecithin, Glyceryl Polymethacrylate, C12-16 Pareth-9, Trideceth-12, Sodium Lactate, Carbomer, Aspartic Acid, Polysorbate 20, Butylene Glycol, Caprylyl Glycol, PEG-8, C11-15 Pareth-7, Guar Hydroxypropyltrimonium Chloride, Phytosteryl/Octyldodecyl Lauroyl Glutamate, Ectoin, Citrate Buffer, Trimethylsiloxyamodimethicone, Phenoxyethanol, Sodium Hydroxide, Ethylhexylglycerin

Niacinamide

Acacia Senegal Gum

Hydrolyzed Rhizobian Gum

Camellia Sinensis Leaf Extract

Chamomilla Recutita Flower Extract

Sh-Oligopeptide-1

Sh-Oligopeptide-2

Sh-Polypeptide-1

Sh-Polypeptide-11

Sh-Polypeptide-9

Sodium Hyaluronate

Acetyl Hexapeptide-8

Acetyl Glutamine

Carnitine

Caffeine

Ruscus Aculeatus Root Extract

Chenopodium Quinoa Seed Extract

Bacillus

Citrus Reticulata Peel Extract

Codonopsis Lanceolata Extract

Coix Lacryma-Jobi Ma-Yuen Seed Extract

Chrysanthemum Parthenium Extract

Digitaria Ciliaris Flower Extract

Glycyrrhiza Glabra Root Extract

Nelumbo Nucifera Seed Extract

Paeonia Suffruticosa Root Extract

Paeonia Albiflora Flower Extract

Polygonum Odoratum Extract

Polyglutamic Acid

Xanthan Gum

1,2-Hexanediol

Citric Acid

Sodium Benzoate

Sodium Levulinate

Potassium Sorbate

Water, Niacinamide, Glycerin, Acacia Senegal Gum, Hydrolyzed Rhizobian Gum, Camellia Sinensis Leaf Extract, Chamomilla Recutita Flower Extract, PCA, Sodium PCA, Sh-Oligopeptide-1, Sh-Oligopeptide-2, Sh-Polypeptide-1, Sh-Polypeptide-11, Sh-Polypeptide-9, Sodium Hyaluronate, Acetyl Hexapeptide-8, Arginine, Aspartic Acid, Acetyl Glutamine, Lecithin, Carnitine, Alanine, Glycine, Histidine, Isoleucine, Phenylalanine, Proline, Serine, Threonine, Valine, Caffeine, Ruscus Aculeatus Root Extract, Chenopodium Quinoa Seed Extract, Bacillus, Citrus Reticulata Peel Extract, Codonopsis Lanceolata Extract, Coix Lacryma-Jobi Ma-Yuen Seed Extract, Chrysanthemum Parthenium Extract, Digitaria Ciliaris Flower Extract, Glycyrrhiza Glabra Root Extract, Nelumbo Nucifera Seed Extract, Paeonia Suffruticosa Root Extract, Paeonia Albiflora Flower Extract, Polygonum Odoratum Extract, Sodium Lactate, Polyglutamic Acid, Xanthan Gum, Butylene Glycol, 1,2-Hexanediol, Citric Acid, Caprylyl Glycol, Sodium Benzoate, Sodium Levulinate, Potassium Sorbate, 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.

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

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.

Aspartic Acid is an amino acid that our bodies produce naturally. It is an antioxidant.

Our body uses Aspartic Acid to help build collagen and elastin. It also plays a role in hydrating skin.

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.

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.

Histidine is a semi-essential amino acid used by our bodies to create protein. It has humectant and skin conditioning properties.

Our bodies use histidine to create filaggrin - filaggrin is a structural protein that the skin uses in maintaining skin barrier.

One study found histidine and carnosine to be a dynamic duo for your skin:

Oral histidine has also been found to help with filaggrin-deficit skin disorders such as atopic dermatitis.

Why is it considered a semi-essential amino acid? This is because adults are able to create it but children must get it from their diet.

Isoleucine is an amino acid that helps reinforce our skin barrier. This amino acid plays a role in creating protein for the body.

Fun fact: Isoleucine is found in meat, fish, dairy, legumes, and nuts.

Lecithin is a term for a group of substances found in the cell membranes of plants, animals, and humans. They are made up of phospholipids.

Thanks to its amphiphilic structure (water-loving head and oil-loving tail), it is a true multitasker:

It plays well with most ingredients and is typically used at 0.1-1%. However, concentrations up to 50% have been reported in moisturizers.

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.

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.

Phenylalanine is an amino acid. It is a skin soothing and hydrating ingredient. Amino acids play a crucial role in wound healing and skin hydration.

This ingredient is also used to help even out skin tone due to its ability to disrupt the melanin production process.

Two structures of phenylalanine exist: L-phenylalanine and D-phenylalanine. L-phenylalanine is essential, this means our bodies cannot produce it naturally and we must get it from foods. Our bodies convert D-phenylalanine to neurotransmitters, and D-phenylalanine is found in our bodies naturally.

Some foods that contain L-phenylalanine include eggs, soybeans, beef, milk.

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 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.

Valine is one of the essential amino acids (meaning your body can't make it on its own and has to get it from food).

In skincare, it's usually synthetically-made or pulled from plant proteins like soy.

It's one of the small building blocks that make up your skin's natural moisturizing factor (NMF), or the built-in system that helps skin hold onto water. So its main job in a formula is to give the skin gentle hydration and help it feel more comfortable.

Typical amounts are very tiny: roughly 0.00004%-0.5% in leave on products and up to 1% in rinse-off ones.

The Cosmetic Ingredient Review panel has looked at this ingredient and found no evidence of it being a skin irritant or allergen at cosmetic levels.

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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