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The INKEY List Hyaluronic Acid Serum Versus The Ordinary Caffeine Solution 5% + EGCG

The INKEY List Hyaluronic Acid Serum Versus The Ordinary Caffeine Solution 5% + EGCG This hydrating serum is formulated around Sodium Hyaluronate and Hyaluronic Acid to hydrate skin and strengthen the skin barrier. This calming eye moisturizer is formulated ar

The INKEY List Hyaluronic Acid Serum Versus The Ordinary Caffeine Solution 5% + EGCG

This hydrating serum is formulated around Sodium Hyaluronate and Hyaluronic Acid to hydrate skin and strengthen the skin barrier.

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

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Propanediol

Sodium Hyaluronate

Glycerin

Butylene Glycol

Phenoxyethanol

Ammonium Acryloyldimethyltaurate/Vp Copolymer

Leuconostoc/Radish Root Ferment Filtrate

Hyaluronic Acid

Carbomer

Sodium Lactate

Polysorbate 20

Palmitoyl Tetrapeptide-7

Palmitoyl Tripeptide-1

Water, Propanediol, Sodium Hyaluronate, Glycerin, Butylene Glycol, Phenoxyethanol, Ammonium Acryloyldimethyltaurate/Vp Copolymer, Leuconostoc/Radish Root Ferment Filtrate, Hyaluronic Acid, Carbomer, Sodium Lactate, Polysorbate 20, Palmitoyl Tetrapeptide-7, Palmitoyl Tripeptide-1

Caffeine

Maltodextrin

Epigallocatechin Gallatyl Glucoside

Gallyl Glucoside

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

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

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.

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.

Hyaluronic acid (HA) is a glycosaminoglycan (basically a long sugar chain) that your skin already makes on its own. In your skin, HA lives in the extracellular matrix and acts as the body's moisture reservoir.

Topically, HA is a humectant that binds water and helps skin look more plump, smooth, and hydrated.

The only catch is that HA isn't a single thing; it actually comes in a wide range of molecular weights (~50 - 2,000+ kDA) and size matters.

Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.

This is why the best HA serums blend the two sizes together so you get the best of both worlds.

The majority of cosmetic HA is produced by bacterial fermentation, typically using Streptococcus or Bacillus strains. Typical use levels in skincare sit around 0.1-2%.

A clinical study using a 0.2% low-molecular weight HA gel showed improvement in facial seborrheic dermatitis with excellent tolerance.

These are some other common types of Hyaluronic Acid:

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!

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

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

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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. 03Acrylates/C10-30 Alkyl Acrylate Crosspolymer is a synthetic polymer. It is used to thicken, emulsify, and improve the texture of products.
  4. 04As an emulsifier, it helps stabilize oil-in-water emulsions to give products an elegant feel when applied.
  5. 05It can also form a thin protective film on skin. One study found that a formula using this polymer helped slow down how quickly other ingredients (like DEET) were absorbed through skin.
  6. 06A 2024 study of over 1,300 patients confirmed that sensitization to this ingredient is rare. It is also non-mutagenic and has a clean track record.
  7. 07Benzyl Alcohol is an aromatic alcohol with several roles: it's a preservative, solvent, and mild fragrance component with a floral scent.
  8. 08This 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.
  9. 09As a preservative, it works by disrupting the membrane of microbial proteins. This helps keep bacteria and fungi from growing in your products.
  10. 10The 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.
  11. 11This led researchers to conclude that benzyl alcohol cannot be regarded as a significant contact allergen.
  12. 12It is worth noting this ingredient is classified as one of the EU's regulated fragrance allergens and restricted to 1% in finished products.
  13. 13Labels must also declare it in concentrations above 0.001% in leave-on products and 0.01% in rinse-off products.
  14. 14At concentrations around 5%, localized redness and itching can appear as a direct irritant response and not as a true allergic reaction.
  15. 15Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:
  16. 16Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.
  17. 17Though 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.
  18. 18Caprylic/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.
  19. 19Though 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.
  20. 20In practice, that translates to a long shelf life and a consistently elegant skin feel.
Source · skinsort.com
02

Product index

Related product references

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03

Comparison edit

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