Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

The INKEY List Collagen Booster Versus Cetaphil Moisturizing Cream

The INKEY List Collagen Booster Versus Cetaphil Moisturizing Cream This anti-aging serum is formulated around Palmitoyl Tetrapeptide-7 and Palmitoyl Tripeptide-1 to soften the look of wrinkles and refine skin texture. This barrier-repair moisturizer is formula

The INKEY List Collagen Booster Versus Cetaphil Moisturizing Cream

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

This barrier-repair moisturizer is formulated around Petrolatum and Panthenol to strengthen the skin barrier and hydrate skin.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Glycerin

Butylene Glycol

Propanediol

Phenoxyethanol

Hydroxyethylcellulose

Disodium EDTA

Leuconostoc/Radish Root Ferment Filtrate

Carbomer

Hyaluronic Acid

Palmitoyl Dipeptide-5 Diaminobutyroyl Hydroxythreonine

Palmitoyl Dipeptide-5 Diaminohydroxybutyrate

Polysorbate 20

Palmitoyl Tetrapeptide-7

Palmitoyl Tripeptide-1

Water, Glycerin, Butylene Glycol, Propanediol, Phenoxyethanol, Hydroxyethylcellulose, Disodium EDTA, Leuconostoc/Radish Root Ferment Filtrate, Carbomer, Hyaluronic Acid, Palmitoyl Dipeptide-5 Diaminobutyroyl Hydroxythreonine, Palmitoyl Dipeptide-5 Diaminohydroxybutyrate, Polysorbate 20, Palmitoyl Tetrapeptide-7, Palmitoyl Tripeptide-1

Petrolatum

Dicaprylyl Ether

Dimethicone

Glyceryl Stearate

Cetyl Alcohol

Helianthus Annuus Seed Oil

PEG-30 Stearate

Panthenol

Niacinamide

Prunus Amygdalus Dulcis Oil

Tocopheryl Acetate

Pantolactone

Dimethiconol

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Propylene Glycol

Benzyl Alcohol

Sodium Hydroxide

Citric Acid

Water, Glycerin, Petrolatum, Dicaprylyl Ether, Dimethicone, Glyceryl Stearate, Cetyl Alcohol, Helianthus Annuus Seed Oil, PEG-30 Stearate, Panthenol, Niacinamide, Prunus Amygdalus Dulcis Oil, Tocopheryl Acetate, Pantolactone, Dimethiconol, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Carbomer, Propylene Glycol, Disodium EDTA, Benzyl Alcohol, Phenoxyethanol, Sodium Hydroxide, Citric Acid

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.

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.

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%.

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.

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.

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. 03Betaine 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.
  4. 04Betaine is mainly used to improve hydration and support calmer skin. It helps skin cells regulate water balance because it functions as an osmolyte.
  5. 05Some studies suggest betaine may support making skin tone more even.
  6. 06Fun 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.
  7. 07Betaine is also known as trimethylglycine.
  8. 08Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.
  9. 09Like 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.
  10. 10However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.
  11. 11Due 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.
  12. 12In skincare formulas, citric acid can:
  13. 13While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.
  14. 14Most 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.
  15. 15Rosacea 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.
  16. 16However, 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…
  17. 17Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
  18. 18The 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 …
  19. 19Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.
  20. 20Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
Source · skinsort.com
02

Product index

Related product references

Product

The Inkey List Brighten-I Eye Cream

The Inkey List Brighten-I Eye Cream The Inkey List Brighten-I Eye Cream ingredients explained: Water (Aqua/Eau), Cyclopentasiloxane, Coco-Caprylate/Caprate, Glycerin, Caprylic/Capric Trigly…

Source: incidecoder.comView reference →
03

Comparison edit

Read side by side