Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

Geek & Gorgeous Power Peptides Serum Versus Medik8 Liquid Peptides Advanced MP

Geek & Gorgeous Power Peptides Serum Versus Medik8 Liquid Peptides Advanced MP This anti-aging serum is formulated around Palmitoyl Tripeptide-1 and Palmitoyl Tetrapeptide-7 to soften the look of wrinkles and refine skin texture. This anti-aging serum is formu

Geek & Gorgeous Power Peptides Serum Versus Medik8 Liquid Peptides Advanced MP

This anti-aging serum is formulated around Palmitoyl Tripeptide-1 and Palmitoyl Tetrapeptide-7 to soften the look of wrinkles and refine skin texture.

This anti-aging serum is formulated around Palmitoyl Tripeptide-38 and Palmitoyl Tripeptide-5 to soften the look of wrinkles and refine skin texture.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Glycerin

Butylene Glycol

Pentylene Glycol

Polyglyceryl-6 Stearate

Caprylic/Capric Triglyceride

Panthenol

Dicaprylyl Carbonate

Dicaprylyl Ether

Potassium Cetyl Phosphate

Polyglyceryl-6 Behenate

Tetrapeptide-21

Palmitoyl Tripeptide-1

Palmitoyl Tetrapeptide-7

Palmitoyl Tripeptide-38

Copper Palmitoyl Heptapeptide-14

Heptapeptide-15 Palmitate

Saccharide Isomerate

Allantoin

Cetearyl Alcohol

Glyceryl Stearate Se

Tapioca Starch

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Carbomer

Polysorbate 20

Hydroxypropyl Cyclodextrin

Lactic Acid/Glycolic Acid Copolymer

Polyvinyl Alcohol

Citric Acid

Sodium Citrate

Sodium Hydroxide

Phenoxyethanol

Ethylhexylglycerin

Water, Glycerin, Butylene Glycol, Pentylene Glycol, Polyglyceryl-6 Stearate, Caprylic/Capric Triglyceride, Panthenol, Dicaprylyl Carbonate, Dicaprylyl Ether, Potassium Cetyl Phosphate, Polyglyceryl-6 Behenate, Tetrapeptide-21, Palmitoyl Tripeptide-1, Palmitoyl Tetrapeptide-7, Palmitoyl Tripeptide-38, Copper Palmitoyl Heptapeptide-14, Heptapeptide-15 Palmitate, Saccharide Isomerate, Allantoin, Cetearyl Alcohol, Glyceryl Stearate Se, Tapioca Starch, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Carbomer, Polysorbate 20, Hydroxypropyl Cyclodextrin, Lactic Acid/Glycolic Acid Copolymer, Polyvinyl Alcohol, Citric Acid, Sodium Citrate, Sodium Hydroxide, Phenoxyethanol, Ethylhexylglycerin

Dimethicone

Dimethyl Isosorbide

Undecane

Arginine

Inulin

Microcrystalline Cellulose

Ceteareth-20

Tridecane

Tocopherol

Hydroxyacetophenone

Sodium Hyaluronate

Palmitoyl Tripeptide-5

Polyacrylate Crosspolymer-6

Pullulan

Palmitoyl Tetrapeptide-10

Ammonium Polyacryloyldimethyl Taurate

Glyceryl Linoleate

Acetyl Hexapeptide-8

Pentapeptide-18

Oligopeptide-1

Arginine/Lysine Polypeptide

Sucrose Palmitate

Cetyl Palmitate

Benzotriazolyl Dodecyl P-Cresol

Polysorbate 80

Sorbitan Stearate

Carnosine

Sodium Metabisulfite

Dunaliella Salina Extract

Helianthus Annuus Seed Oil

Dimethicone/Vinyl Dimethicone Crosspolymer

Sodium Benzoate

Hydrogenated Lecithin

Caprylyl Glycol

Pantolactone

Xanthan Gum

Disodium EDTA

T-Butyl Alcohol

Potassium Sorbate

Glyceryl Caprylate

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

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.

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.

Caprylic/Capric Triglyceride (aka MCT Oil) is a lightweight emollient, solvent, and texture enhancer. It is considered a skin-softener by helping to prevent moisture loss.

Though it behaves like an oil, it is not technically one due to its chemical composition. One perk of this ingredient is that it is very stable, resistant to oxidation, and unlikely to go rancid.

In practice, that translates to a long shelf life and a consistently elegant skin feel.

While there is an assumption Caprylic Triglyceride can clog pores due to it being derived from coconut oil, there is no research supporting this. Just patch test if you have concerns.

Fractionated coconut oil and MCT Oil are both listed as Caprylic/Capric Triglyceride according to INCI. This is because INCI names are based on the ingredient’s final chemical composition and not its marketing name or source.

This ingredient is treated as the gold standard fungal acne safe oil. Even though it is coconut derived, the problematic lauric acid is stripped out.

This leaves just caprylic (C8) and capric (C10) acid. These chain lengths actually trend antifungal; a 2020 study found caprylic acid was enough to disrupt Malassezia furfur cell membrane, with a caprylic acid derivative damaging membrane structures at concentrations as low as 0.2%.

Carbomer is a synthetic thickening and gelling agent. It's basically the ingredient that gives a lot of serums, gels, creams, and sunscreens their smooth, non-sticky texture.

Although legally permitted at very high levels, carbomers are normally used at concentrations below 1%.

It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.

Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.

A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.

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.

This peptide is the copper salt and formed by reacting palmitic acid and heptapeptide-14.

This uses a high-tech delivery system called The Cosmetic Drone, where the peptide is enclosed in a shell made from Lactic Acid/Glycolic Acid Copolymer and Polyvinyl Alcohol. Another peptide on the outside guides the capsule to fibroblast cells, the collagen-producing cells in the skin.

Once it reaches the fibroblasts, Copper Palmitoyl Heptapeptide-14 boosts the production of collagen and elastin.

This advanced system works at an incredibly low concentration of just 0.001%.

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.

Heptapeptide-15 Palmitate is a synthetic targeting peptide. It's made up of seven amino acids with a palmitic acid tail attached.

This fatty acid attachment increases the molecule's hydrophobicity, improves stability, reduces enzyme degradation, and enhances its ability to cross the skin's lipid barrier (this is a common challenge for peptides).

As a targeting peptide, it sits on the outer shell of an encapsulated ingredient system and seeks out receptors on collagen and elastin producing cells in skin.

Once it binds, the cell internalizes the capsule and releases the active payload inside; it essentially acts as a GPS guiding ingredients to the right place.

It also mimicks the skin's natural growth factors to support skin firmness by upping production of collagen, elastin, glycosaminoglycans (GAGs).

Most of the evidence for this ingredient comes from manufacturer in vitro data, so independent clinical trials are still limited. However, the underlying mechanism is well-supported by the broader cosmetic peptide literature.

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 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.

This ingredient is a combination of two AHAs, lactic acid and glycolic acid. It has exfoliating properties

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.

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.

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.

Panthenol is a common ingredient that helps hydrate and soothe the skin. It is found naturally in our skin and hair.

There are two forms of panthenol: D and L.

D-panthenol is also known as dexpanthenol. Most cosmetics use dexpanthenol or a mixture of D and L-panthenol.

Panthenol is famous due to its ability to go deeper into the skin's layers. Using this ingredient has numerous pros (and no cons):

Like hyaluronic acid, panthenol is a humectant. Humectants are able to bind and hold large amounts of water to keep skin hydrated.

This ingredient works well for wound healing. It works by increasing tissue in the wound and helps close open wounds.

Once oxidized, panthenol converts to pantothenic acid. Panthothenic acid is found in all living cells.

This ingredient is also referred to as pro-vitamin B5.

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.

Polysorbate 20 is a gentle, water-soluble emulsifier and mild surfactant. It stops oil and water from separating to keep your formulas blended and stable.

It also acts as a mild penetration enhancer by helping active ingredients absorb slightly better.

The common safety discussion around this ingredient involves a manufacturing byproduct called 1,4-dioxane.

Trace amounts can form during production but the EU's Scientific Committee on Consumer Safety has concluded that levels at/below 10 ppm in finished products are safe (commercial products consistently fall within acceptable margins).

True allergic reactions are uncommon and the CIR Expert Panel has confirmed this ingredient to be safe as used in cosmetics.

Because it is derived from lauric acid, it may not be fungal acne safe.

We don't have a description for Polyvinyl Alcohol yet.

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!

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

Connected source records selected through this article’s public topic index.

01

Formula cabinet

Ingredients & structured notes

Ingredient index

Ingredients Explained

  1. 01These ingredients are found in both products.
  2. 02Ingredients higher up in an ingredient list are typically present in a larger amount.
  3. 03Allantoin 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.
  4. 04Though it can be derived from the comfrey plant, allantoin is produced synthetically for cosmetic products to ensure purity.
  5. 05Research shows it can encourage your skin cells to turn over and renew by stimulating keratinocyte and fibroblast proliferation.
  6. 06It also has mild keratolytic properties to help loosen and shed dead skin cells without being harsh.
  7. 07Studies also suggest allantoin can help calm inflammation by dialing down some of the chemical signals your skin sends out when it is irritated.
  8. 08This 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%.
  9. 09Overall, 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.
  10. 10Fun 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.
  11. 11Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:
  12. 12Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.
  13. 13Though 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.
  14. 14Carbomer is a synthetic thickening and gelling agent. It's basically the ingredient that gives a lot of serums, gels, creams, and sunscreens their smooth, non-sticky texture.
  15. 15Although legally permitted at very high levels, carbomers are normally used at concentrations below 1%.
  16. 16It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.
  17. 17Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.
  18. 18A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.
  19. 19Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
  20. 20The 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 …
Source · skinsort.com
02

Product index

Related product references

Product

Geek & Gorgeous Power Peptides Serum

Geek & Gorgeous Power Peptides Serum Ingredients in Geek & Gorgeous Power Peptides Serum explained: benefits, concerns, and detailed analysis of 33 ingredients including Water, Glycerin, an…

Source: skinsort.comView reference →

Product

Medik8 Liquid Peptides Advanced Mp

Medik8 Liquid Peptides Advanced Mp Medik8 Liquid Peptides Advanced Mp ingredients explained: Aqua (Water), Glycerin, Dimethicone, Dimethyl Isosorbide, Butylene Glycol, Undecane, Arginine, I…

Source: incidecoder.comView reference →

Product

Medik8 Liquid Peptides Advanced MP

Medik8 Liquid Peptides Advanced MP Ingredients in Medik8 Liquid Peptides Advanced MP explained: benefits, concerns, and detailed analysis of 60 ingredients including Water, Glycerin, and Di…

Source: skinsort.comView reference →
03

Comparison edit

Read side by side