Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

The Ordinary Caffeine Solution 5% + EGCG Versus The INKEY List Retinol Eye Cream

The Ordinary Caffeine Solution 5% + EGCG Versus The INKEY List Retinol Eye Cream This calming eye moisturizer is formulated around Caffeine and Epigallocatechin Gallatyl Glucoside to calm redness and soften the look of wrinkles. This anti-aging eye moisturizer

The Ordinary Caffeine Solution 5% + EGCG Versus The INKEY List Retinol Eye Cream

This calming eye moisturizer is formulated around Caffeine and Epigallocatechin Gallatyl Glucoside to calm redness and soften the look of wrinkles.

This anti-aging eye moisturizer is formulated around Retinol and Sodium Hyaluronate to soften the look of wrinkles and refine skin texture.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Caffeine

Maltodextrin

Glycerin

Propanediol

Epigallocatechin Gallatyl Glucoside

Gallyl Glucoside

Hyaluronic Acid

Oxidized Glutathione

Melanin

Glycine Soja Seed Extract

Pentylene Glycol

Hydroxyethylcellulose

Polyacrylate Crosspolymer-6

Xanthan Gum

Lactic Acid

Dehydroacetic Acid

Trisodium Ethylenediamine Disuccinate

Propyl Gallate

Dimethyl Isosorbide

Benzyl Alcohol

1,2-Hexanediol

Ethylhexylglycerin

Phenoxyethanol

Caprylyl Glycol

Water, Caffeine, Maltodextrin, Glycerin, Propanediol, Epigallocatechin Gallatyl Glucoside, Gallyl Glucoside, Hyaluronic Acid, Oxidized Glutathione, Melanin, Glycine Soja Seed Extract, Pentylene Glycol, Hydroxyethylcellulose, Polyacrylate Crosspolymer-6, Xanthan Gum, Lactic Acid, Dehydroacetic Acid, Trisodium Ethylenediamine Disuccinate, Propyl Gallate, Dimethyl Isosorbide, Benzyl Alcohol, 1,2-Hexanediol, Ethylhexylglycerin, Phenoxyethanol, Caprylyl Glycol

Caprylic/Capric Triglyceride

Butylene Glycol

Pentaerythrityl Distearate

Shea Butter Ethyl Esters

Cetearyl Olivate

Sorbitan Olivate

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Sodium Hydroxide

Sodium Hyaluronate

Sodium Stearoyl Glutamate

Copernicia Cerifera Cera

Glycogen

Sodium Gluconate

Retinol

Polysorbate 20

Citric Acid

Helianthus Annuus Seed Oil

Disodium Cocoamphodiacetate

Tocopherol

Ethyl Ferulate

Humulus Lupulus Extract

Water, Caprylic/Capric Triglyceride, Glycerin, Butylene Glycol, Pentaerythrityl Distearate, Shea Butter Ethyl Esters, Cetearyl Olivate, Phenoxyethanol, Benzyl Alcohol, Sorbitan Olivate, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Sodium Hydroxide, Sodium Hyaluronate, Sodium Stearoyl Glutamate, Copernicia Cerifera Cera, Propanediol, Glycogen, Sodium Gluconate, Retinol, Polysorbate 20, Ethylhexylglycerin, Dehydroacetic Acid, Citric Acid, Helianthus Annuus Seed Oil, 1,2-Hexanediol, Caprylyl Glycol, Disodium Cocoamphodiacetate, Tocopherol, Xanthan Gum, Ethyl Ferulate, Humulus Lupulus Extract

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.

1,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse.

It is a:

Humectant, drawing moisture into the skin

Emollient, helping to soften skin

Solvent, dispersing and stabilizing formulas

Preservative booster, enhancing the antimicrobial activity of other preservatives

Benzyl Alcohol is an aromatic alcohol with several roles: it's a preservative, solvent, and mild fragrance component with a floral scent.

This ingredient has been deemed safe for use in cosmetic formulations at concentrations up to 5%, and up to 10% in hair dyes. You'll typically see 0.5-2% in most rinse-off or leave-on products.

As a preservative, it works by disrupting the membrane of microbial proteins. This helps keep bacteria and fungi from growing in your products.

The sensitization picture is actually quite assuring as well:of nearly 71,000 patients patch tested with benzyl alcohol, only 0.21% showed a positive reaction with most of them being weakly positive.

This led researchers to conclude that benzyl alcohol cannot be regarded as a significant contact allergen.

It is worth noting this ingredient is classified as one of the EU's regulated fragrance allergens and restricted to 1% in finished products.

Labels must also declare it in concentrations above 0.001% in leave-on products and 0.01% in rinse-off products.

At concentrations around 5%, localized redness and itching can appear as a direct irritant response and not as a true allergic reaction.

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).

Dehydroacetic Acid is a synthetic preservative that keeps your products safe from microbes.

As an organic acid, it penetrates microbial cell walls and disrupts cellular metabolism. This makes it effective against bacteria, yeast, and mold.

It is effective at low concentrations (<0.6%). Clinical studies have found it to be non-irritating, non-sensitizing, and non-photosensitizing.

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.

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.

Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.

It’s often used to:

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

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.

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 Side-by-side

  1. 01Squalane
  2. 02Caprylic/Capric Triglyceride
  3. 03Carthamus Tinctorius Seed Oil
  4. 04Dimethicone
  5. 05PPG-12/Smdi Copolymer
  6. 06Tocopheryl Acetate
  7. 07Retinol
  8. 08Climbazole
  9. 09Pogostemon Cablin Leaf Oil
  10. 10Decylene Glycol
  11. 11Phenoxyethanol
  12. 121,2-Hexanediol
  13. 13BHT
  14. 14Lecithin
  15. 15Squalane, Caprylic/Capric Triglyceride, Carthamus Tinctorius Seed Oil, Dimethicone, PPG-12/Smdi Copolymer, Tocopheryl Acetate, Retinol, Climbazole, Pogostemon Cablin Leaf Oil, Decylene Glycol, Phenoxyethanol, 1,2-Hexanediol, BHT, Lecithin
  16. 16Water
  17. 17Glycerin
  18. 18Prunus Armeniaca Kernel Oil
  19. 19Persea Gratissima Oil
  20. 20Cetearyl Alcohol
Source · skinsort.com
02

Product index

Related product references

03

Comparison edit

Read side by side