Allies of Skin Tranexamic & Arbutin Advanced Brightening Serum Versus Medik8 C-Tetra™ Advanced Gel-Serum

Allies of Skin Tranexamic & Arbutin Advanced Brightening Serum Versus Medik8 C-Tetra™ Advanced Gel-Serum

This brightening serum is formulated around Tranexamic Acid and Alpha-Arbutin to fade the look of dark spots and brighten dull-looking skin.

This brightening serum is formulated around Tetrahexyldecyl Ascorbate and Acetyl Glucosamine to brighten dull-looking skin and soften the look of wrinkles.

What's inside

Key Ingredients

Benefits

Concerns

No concerns

Ingredients Side-by-side

Water

Caprylic/Capric Triglyceride

C13-15 Alkane

Tranexamic Acid

Glycerin

Alpha-Arbutin

Pentylene Glycol

Tocopheryl Acetate

Palmaria Palmata Extract

Hydrolyzed Pea

Asparagopsis Armata Extract

Ascophyllum Nodosum Extract

Glycyrrhiza Glabra Root Extract

Pancratium Maritimum Extract

Ganoderma Lucidum Extract

Lentinus Edodes Extract

Lactobacillus Ferment

Hydrolyzed Pea Protein

Diacetyl Boldine

Dipotassium Glycyrrhizate

Lactobacillus

Bisabolol

Panthenol

Tocopherol

Glucose

Arginine/Lysine Polypeptide

Pentapeptide-34 Trifluoroacetate

C14-22 Alcohols

Xanthan Gum

Hydrogenated Starch Hydrolysate

Hydroxyacetophenone

Sorbitan Caprylate

1,2-Hexanediol

Caprylyl Glycol

C12-20 Alkyl Glucoside

Propanediol

Carbomer

Sodium Phytate

Butylene Glycol

Sodium Chloride

Sodium Succinate

Sorbic Acid

Sodium Benzoate

Potassium Sorbate

Phenoxyethanol

Water, Caprylic/Capric Triglyceride, C13-15 Alkane, Tranexamic Acid, Glycerin, Alpha-Arbutin, Pentylene Glycol, Tocopheryl Acetate, Palmaria Palmata Extract, Hydrolyzed Pea, Asparagopsis Armata Extract, Ascophyllum Nodosum Extract, Glycyrrhiza Glabra Root Extract, Pancratium Maritimum Extract, Ganoderma Lucidum Extract, Lentinus Edodes Extract, Lactobacillus Ferment, Hydrolyzed Pea Protein, Diacetyl Boldine, Dipotassium Glycyrrhizate, Lactobacillus, Bisabolol, Panthenol, Tocopherol, Glucose, Arginine/Lysine Polypeptide, Pentapeptide-34 Trifluoroacetate, C14-22 Alcohols, Xanthan Gum, Hydrogenated Starch Hydrolysate, Hydroxyacetophenone, Sorbitan Caprylate, 1,2-Hexanediol, Caprylyl Glycol, C12-20 Alkyl Glucoside, Propanediol, Carbomer, Sodium Phytate, Butylene Glycol, Sodium Chloride, Sodium Succinate, Sorbic Acid, Sodium Benzoate, Potassium Sorbate, Phenoxyethanol

Tetrahexyldecyl Ascorbate

Isododecane

Acetyl Glucosamine

Squalane

Acetyl Zingerone

Camellia Sinensis Leaf

Sodium Hyaluronate

Cellulose

Avena Sativa Kernel Extract

Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer

Citrus Grandis Peel Oil

Sucrose Stearate

Tetrasodium Glutamate Diacetate

Ethylhexylglycerin

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Cellulose Gum

Polysorbate 60

Sorbitan Isostearate

Citric Acid

Citral

Linalool

Limonene

Water, Tetrahexyldecyl Ascorbate, Isododecane, Propanediol, Acetyl Glucosamine, Squalane, Tocopherol, Acetyl Zingerone, Camellia Sinensis Leaf, Hydroxyacetophenone, Sodium Hyaluronate, Cellulose, Avena Sativa Kernel Extract, Glycerin, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Citrus Grandis Peel Oil, Sucrose Stearate, Tetrasodium Glutamate Diacetate, Ethylhexylglycerin, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Xanthan Gum, Sodium Benzoate, Cellulose Gum, 1,2-Hexanediol, Polysorbate 60, Sorbitan Isostearate, Citric Acid, Phenoxyethanol, Citral, Linalool, Limonene

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

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.

Hydroxyacetophenone is a small phenolic molecule that earns its place in a formulas as an antioxidant and preservative booster.

As a phenol, it is able to neutralize free radicals to protect both the product and the skin from oxidative stress.

Though it can't kill microbes on its own, it works as a good supporting agent when combined with other preservatives like Phenoxyethanol or 1,2-Hexanediol.

This ingredient naturally occurs as piceol in Norwegian spruce needles (~0.4-1.1% dry weight and in cloudberries). Though the cosmetic-grade material is synthesized for purity and consistency.

You'll usually see it used at low levels and suppliers recommend up to 1% added to a water phase.

Safety testing was done at concentrations like 0.05% in SPF products and 0.5% in a Human Repeated Insult Patch Test. The safety evidence is assuring; this ingredient is safe for cosmetics in current use and also holds safety status as a food flavoring as well.

An honest caveat: the "soothing" and "anti-inflammatory" claims come mostly from supplier marketing rather than published clinical trials. The Cosmetic Ingredient Review's own literature search found no useful efficacy studies on this ingredient.

So the antioxidant and preservative-boosting roles are the well supported ones while the calming benefit is plausible but thinly evidenced.

Overall, this is a well-tolerated, low-irritation multitasker that quietly helps a formula stay fresh and stable.

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.

Sodium Benzoate is a preservative. It's used in both cosmetic and food products to inhibit the growth of mold and bacteria. It is typically produced synthetically.

Both the US FDA and EU Health Committee have approved the use of sodium benzoate. In the US, levels of 0.1% (of the total product) are allowed.

Sodium benzoate works as a preservative by inhibiting the growth of bacteria inside of cells. It prevents the cell from fermenting a type of sugar using an enzyme called phosphofructokinase.

It is the salt of benzoic acid. Foods containing sodium benzoate include soda, salad dressings, condiments, fruit juices, wines, and snack foods.

Studies for using ascorbic acid and sodium benzoate in cosmetics are lacking, especially in skincare routines with multiple steps.

We always recommend speaking with a professional, such as a dermatologist, if you have any concerns.

Tocopherol is a fat-soluble antioxidant known as Vitamin E.

You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.

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.

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