Skin science article
Medik8 Liquid Peptides Advanced MP Versus Peach & Lily Copper Peptide Pro Firming Serum
Medik8 Liquid Peptides Advanced MP Versus Peach & Lily Copper Peptide Pro Firming Serum This anti-aging serum is formulated around Palmitoyl Tripeptide-38 and Palmitoyl Tripeptide-5 to soften the look of wrinkles and refine skin texture. This anti-aging serum
Medik8 Liquid Peptides Advanced MP Versus Peach & Lily Copper Peptide Pro Firming Serum
This anti-aging serum is formulated around Palmitoyl Tripeptide-38 and Palmitoyl Tripeptide-5 to soften the look of wrinkles and refine skin texture.
This anti-aging serum is formulated around Copper Tripeptide-1 and Acetyl Hexapeptide-8 to soften the look of wrinkles.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Glycerin
Dimethicone
Dimethyl Isosorbide
Butylene Glycol
Undecane
Arginine
Inulin
Microcrystalline Cellulose
Ceteareth-20
Tridecane
Tocopherol
Hydroxyacetophenone
Sodium Hyaluronate
Palmitoyl Tripeptide-38
Panthenol
Caprylic/Capric Triglyceride
Palmitoyl Tripeptide-5
Polyacrylate Crosspolymer-6
Palmitoyl Tripeptide-1
Pullulan
Tetrapeptide-21
Palmitoyl Tetrapeptide-10
Palmitoyl Tetrapeptide-7
Ammonium Polyacryloyldimethyl Taurate
Glyceryl Linoleate
Acetyl Hexapeptide-8
Pentapeptide-18
Oligopeptide-1
Arginine/Lysine Polypeptide
Sucrose Palmitate
Cetyl Palmitate
Phenoxyethanol
Ethylhexylglycerin
Carbomer
Copper Palmitoyl Heptapeptide-14
Heptapeptide-15 Palmitate
Benzotriazolyl Dodecyl P-Cresol
Polysorbate 80
Sorbitan Stearate
Polysorbate 20
Carnosine
Sodium Metabisulfite
Dunaliella Salina Extract
Helianthus Annuus Seed Oil
Hydroxypropyl Cyclodextrin
Dimethicone/Vinyl Dimethicone Crosspolymer
Sodium Benzoate
Hydrogenated Lecithin
Caprylyl Glycol
Pantolactone
Xanthan Gum
Disodium EDTA
T-Butyl Alcohol
Potassium Sorbate
Citric Acid
Glyceryl Caprylate
Lactic Acid/Glycolic Acid Copolymer
Polyvinyl Alcohol
Phenylpropanol
Water, Glycerin, Dimethicone, Dimethyl Isosorbide, Butylene Glycol, Undecane, Arginine, Inulin, Microcrystalline Cellulose, Ceteareth-20, Tridecane, Tocopherol, Hydroxyacetophenone, Sodium Hyaluronate, Palmitoyl Tripeptide-38, Panthenol, Caprylic/Capric Triglyceride, Palmitoyl Tripeptide-5, Polyacrylate Crosspolymer-6, Palmitoyl Tripeptide-1, Pullulan, Tetrapeptide-21, Palmitoyl Tetrapeptide-10, Palmitoyl Tetrapeptide-7, Ammonium Polyacryloyldimethyl Taurate, Glyceryl Linoleate, Acetyl Hexapeptide-8, Pentapeptide-18, Oligopeptide-1, Arginine/Lysine Polypeptide, Sucrose Palmitate, Cetyl Palmitate, Phenoxyethanol, Ethylhexylglycerin, Carbomer, Copper Palmitoyl Heptapeptide-14, Heptapeptide-15 Palmitate, Benzotriazolyl Dodecyl P-Cresol, Polysorbate 80, Sorbitan Stearate, Polysorbate 20, Carnosine, Sodium Metabisulfite, Dunaliella Salina Extract, Helianthus Annuus Seed Oil, Hydroxypropyl Cyclodextrin, Dimethicone/Vinyl Dimethicone Crosspolymer, Sodium Benzoate, Hydrogenated Lecithin, Caprylyl Glycol, Pantolactone, Xanthan Gum, Disodium EDTA, T-Butyl Alcohol, Potassium Sorbate, Citric Acid, Glyceryl Caprylate, Lactic Acid/Glycolic Acid Copolymer, Polyvinyl Alcohol, Phenylpropanol
Dipropylene Glycol
1,2-Hexanediol
Betaine
Copper Tripeptide-1
Tetrapeptide-30
Heptasodium Hexacarboxymethyl Dipeptide-12
Acetyl Tetrapeptide-5
Palmitoyl Pentapeptide-4
Dipeptide-2
Tripeptide-1
Hexapeptide-9
Nonapeptide-1
Collagen Extract
Serine
Methionine
Cysteine
Acmella Oleracea Extract
Alpha-Glucan Oligosaccharide
Sodium PCA
Ulmus Davidiana Root Extract
Cichorium Intybus Root Extract
Helianthus Tuberosus Root Extract
Tremella Fuciformis Extract
Fomes Officinalis Extract
Lentinus Edodes Extract
Pyrus Malus Fruit Extract
Lens Esculenta Fruit Extract
Citrullus Lanatus Fruit Extract
Sodium Acetylated Hyaluronate
Hydrolyzed Hyaluronic Acid
Hyaluronic Acid
Sodium Hyaluronate Crosspolymer
Potassium Hyaluronate
Squalane
Ficus Carica Fruit Extract
Cynanchum Atratum Extract
Hydroxypropyltrimonium Hyaluronate
Ocimum Sanctum Leaf Extract
Melia Azadirachta Leaf Extract
Curcuma Longa Root Extract
Corallina Officinalis Extract
Solanum Melongena Fruit Extract
Coccinia Indica Fruit Extract
Gellan Gum
Adenosine
Aloe Barbadensis Flower Extract
Melia Azadirachta Flower Extract
Polyglyceryl-10 Eicosanedioate/Tetradecanedioate
Polyquaternium-51
Sodium Polyacryloyldimethyl Taurate
Hydroxyethylcellulose
Water, Dipropylene Glycol, Glycerin, 1,2-Hexanediol, Betaine, Copper Tripeptide-1, Acetyl Hexapeptide-8, Palmitoyl Tripeptide-1, Tetrapeptide-21, Tetrapeptide-30, Heptasodium Hexacarboxymethyl Dipeptide-12, Acetyl Tetrapeptide-5, Palmitoyl Tripeptide-38, Palmitoyl Pentapeptide-4, Dipeptide-2, Tripeptide-1, Hexapeptide-9, Nonapeptide-1, Collagen Extract, Serine, Methionine, Cysteine, Arginine, Acmella Oleracea Extract, Alpha-Glucan Oligosaccharide, Sodium PCA, Ulmus Davidiana Root Extract, Cichorium Intybus Root Extract, Helianthus Tuberosus Root Extract, Tremella Fuciformis Extract, Fomes Officinalis Extract, Lentinus Edodes Extract, Pyrus Malus Fruit Extract, Lens Esculenta Fruit Extract, Citrullus Lanatus Fruit Extract, Sodium Acetylated Hyaluronate, Hydrolyzed Hyaluronic Acid, Hyaluronic Acid, Sodium Hyaluronate, Sodium Hyaluronate Crosspolymer, Potassium Hyaluronate, Squalane, Ficus Carica Fruit Extract, Cynanchum Atratum Extract, Hydroxypropyltrimonium Hyaluronate, Ocimum Sanctum Leaf Extract, Melia Azadirachta Leaf Extract, Curcuma Longa Root Extract, Corallina Officinalis Extract, Solanum Melongena Fruit Extract, Coccinia Indica Fruit Extract, Gellan Gum, Butylene Glycol, Adenosine, Aloe Barbadensis Flower Extract, Melia Azadirachta Flower Extract, Polyglyceryl-10 Eicosanedioate/Tetradecanedioate, Polyquaternium-51, Sodium Polyacryloyldimethyl Taurate, Hydroxypropyl Cyclodextrin, Ethylhexylglycerin, Hydroxyethylcellulose, Caprylyl Glycol
Reviews
Alternatives
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
Acetyl Hexapeptide-8 (also known as Argireline) is a synthetic hexapeptide that is often called a "topical Botox alternative".
It works by mimicking how Botox relaxes muscles; it interferes with the signaling process that tells your facial muscles to contract. This can help soften expression lines like forehead wrinkles or crow's feet over time.
The comparison to Botox does have limits because the molecule is water-loving and relatively large.
Acetyl Hexapeptide-8 has a hard time absorbing deeply enough through the skin's outer barrier to actually reach the muscles.
So whether it truly works the way Botox does at a biological level is still up for debate, but early clinical outcomes are fairly encouraging.
A 12 week human study of a multi-ingredient regimen containing this ingredient saw:
While some studies have observed improvements in wrinkle appearance, it is important to note that more consistent results are seen in multi-ingredient formulations (vs just Acetyl Hexapeptide-8 alone).
Some research studies also used higher concentrations (up to 10%) while this ingredient is usually found in concentrations up to 0.005% in leave-on formulations.
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.
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).
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.
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.
This ingredient is used in skincare as a delivery system.
It works by "encapsulating" active ingredients with its unique ring shape that is water-loving on the outside and oil-loving on the inside. This improves the stability and absorption of the product into the skin.
According to a manufacturer, it also offer some moisturizing effects.
Palmitoyl Tripeptide-1 (aka Pal-GHK) is a synthetic signal peptide made of three amino acids attached to palmitic acid.
That fatty acid attachment is the key: it boosts the peptide's ability to penetrate the skin barrier. This puts it closer to the dermal cells where it can actually make a difference.
Once there, it acts as a matrikine, a signaling peptide that prompts fibroblasts to produce more collagen, fibronectin, and hyaluronic acid.
In vitro studies show it can boost collagen production in skin cells even when UV-damaged skin samples were treated with it at a tiny concentration (it almost fully restored dermal collagen at 5ppm). It achieved this at 100x lower concentration than retinoic acid, which needed 500 ppm to do the same thing.
Human clinical data is promising, but modest:
A study of 23 female volunteers found a small but statistically significant increase (~4%) in skin thickness after treatment at 4 ppm.
A separate small trial of 15 women showed statistically significant reductions in wrinkle length, depth, and skin roughness after applying it twice daily for four weeks.
You'll likely see Pal-GHK paired with Palmitoyl Tetrapeptide-7 as part of the Matrixyl 3000 complex.
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.
This synthetic, signal peptide has unique skin conditioning properties in that is a matrikine-mimetic compound.
First of all, Palmitoyl Tripeptide-38 is a signal peptide; signal peptides tell the body to create more collagen.
What is a matrikine-mimetic compound?
This peptide has the ability to mimic matrikines in skin. Our skin created matrikines by breaking down matrix proteins into peptides.
Matrikines play a role in:
Though further research is needed, this ingredient seems pretty promising. In one study, women over the age of 40 with visible photoaging used a vitamin C serum with this ingredient for 56 days (15% ascorbid acid, 5 ppm palmitoyl tripeptide‐38). The results found improvement in skin roughness and skin tone.
This peptide is also part of the famous Matrixyl synthe’6, a blend of ingredients that also includes glycerin, water, and hydroxypropyl cyclodextrin.
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.
Tetrapeptide-21 is a signal peptide. It helps boost collagen, hyaluronic acid, and fibronectin.
Fibronectin is a protein found in our skin's extracellular matrix that plays a role in cell adhesion, tissue repair, and wound healing.
Tetrapeptide-21 works by mimicking skin-protein breakdown signals, telling the skin to produce new structural proteins like collagen.
Preliminary studies show it works better than matrixyl and produced twice the amount of collagen in lab tests.
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!