Skin science article
The INKEY List Alpha Arbutin Serum Versus The INKEY List Hyaluronic Acid Serum
The INKEY List Alpha Arbutin Serum Versus The INKEY List Hyaluronic Acid Serum This brightening serum is formulated around Alpha-Arbutin to fade the look of dark spots and brighten dull-looking skin. This hydrating serum is formulated around Sodium Hyaluronate
The INKEY List Alpha Arbutin Serum Versus The INKEY List Hyaluronic Acid Serum
This brightening serum is formulated around Alpha-Arbutin to fade the look of dark spots and brighten dull-looking skin.
This hydrating serum is formulated around Sodium Hyaluronate and Hyaluronic Acid to hydrate skin and strengthen the skin barrier.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Butylene Glycol
Propanediol
Glycerin
Alpha-Arbutin
Dicaprylyl Carbonate
Caprylic/Capric Triglyceride
Phenoxyethanol
Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
Caprylyl Glycol
Squalane
Phospholipids
Glycine Soja Oil
Carbomer
Polysorbate 60
Sodium Phytate
Glycolipids
Sorbitan Isostearate
Leuconostoc/Radish Root Ferment Filtrate
Sodium Hydroxide
Glycine Soja Sterols
Hyaluronic Acid
Tocopherol
Water, Butylene Glycol, Propanediol, Glycerin, Alpha-Arbutin, Dicaprylyl Carbonate, Caprylic/Capric Triglyceride, Phenoxyethanol, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Caprylyl Glycol, Squalane, Phospholipids, Glycine Soja Oil, Carbomer, Polysorbate 60, Sodium Phytate, Glycolipids, Sorbitan Isostearate, Leuconostoc/Radish Root Ferment Filtrate, Sodium Hydroxide, Glycine Soja Sterols, Hyaluronic Acid, Tocopherol
Sodium Hyaluronate
Ammonium Acryloyldimethyltaurate/Vp Copolymer
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
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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.
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.
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:
Leuconostoc/Radish Root Ferment Filtrate is a natural preservative. It comes from fermenting radish roots with a bacteria called leuconostoc. The trade name for this ingredient is Leucidal.
Leuconostoc comes from lactic acid.
This ingredient has antimicrobial properties and helps prevent the growth of bacteria in a product.
Leuconostoc is used to make the traditional Korean side-dish, kimchi. It is also used to make sourdough bread (both incredibly yummy foods).
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!