Allies of Skin 20% Vitamin C Brighten + Firm Serum Versus Youth To The People 15% Vitamin C + Clean Caffeine Energy Serum

Allies of Skin 20% Vitamin C Brighten + Firm Serum Versus Youth To The People 15% Vitamin C + Clean Caffeine Energy Serum

This brightening serum is formulated around 3-O-Ethyl Ascorbic Acid and Glutathione to brighten dull-looking skin.

This brightening serum is formulated around 3-O-Ethyl Ascorbic Acid and Tetrahexyldecyl Ascorbate to brighten dull-looking skin and fade the look of dark spots.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Propanediol

Glycerin

3-O-Ethyl Ascorbic Acid

Benzimidazole Diamond Amidoethyl Urea Carbamoyl Propyl Polymethylsilsesquioxane

Dimethyl Isosorbide

Helianthus Annuus Seed Wax

Polyglyceryl-10 Tristearate

Ethoxydiglycol

Dicaprylyl Ether

Water

Caprylyl Glycol

Citrus Aurantium Dulcis Callus Culture Extract

Glutathione

Acetyl Cysteine

Dimethylmethoxy Chromanol

Ergothioneine

Tocopherol

Gluconolactone

Leuconostoc/Radish Root Ferment Filtrate

Xanthan Gum

Silica

Sodium Benzoate

Calcium Gluconate

Phenoxyethanol

Propanediol, Glycerin, 3-O-Ethyl Ascorbic Acid, Benzimidazole Diamond Amidoethyl Urea Carbamoyl Propyl Polymethylsilsesquioxane, Dimethyl Isosorbide, Helianthus Annuus Seed Wax, Polyglyceryl-10 Tristearate, Ethoxydiglycol, Dicaprylyl Ether, Water, Caprylyl Glycol, Citrus Aurantium Dulcis Callus Culture Extract, Glutathione, Acetyl Cysteine, Dimethylmethoxy Chromanol, Ergothioneine, Tocopherol, Gluconolactone, Leuconostoc/Radish Root Ferment Filtrate, Xanthan Gum, Silica, Sodium Benzoate, Calcium Gluconate, Phenoxyethanol

Tetrahexyldecyl Ascorbate

Pentylene Glycol

Sodium Citrate

Squalane

Triethyl Citrate

Citric Acid

Polyhydroxystearic Acid

Polyglyceryl-6 Polyricinoleate

Sodium Hyaluronate

Caffeine

Magnesium Ascorbyl Phosphate

Sodium Stearoyl Glutamate

Lauroyl Lysine

Passiflora Edulis Fruit Extract

Sclerotium Gum

Lecithin

Ilex Guayusa Leaf Extract

Ilex Paraguariensis Leaf Extract

Pullulan

Mannitol

Hylocereus Undatus Fruit Extract

Zingiber Officinale Root Oil

Potassium Sorbate

Water, 3-O-Ethyl Ascorbic Acid, Tetrahexyldecyl Ascorbate, Propanediol, Glycerin, Pentylene Glycol, Sodium Citrate, Squalane, Triethyl Citrate, Gluconolactone, Citric Acid, Polyhydroxystearic Acid, Polyglyceryl-6 Polyricinoleate, Xanthan Gum, Sodium Hyaluronate, Caffeine, Magnesium Ascorbyl Phosphate, Sodium Stearoyl Glutamate, Sodium Benzoate, Lauroyl Lysine, Passiflora Edulis Fruit Extract, Sclerotium Gum, Lecithin, Ilex Guayusa Leaf Extract, Ilex Paraguariensis Leaf Extract, Pullulan, Mannitol, Hylocereus Undatus Fruit Extract, Zingiber Officinale Root Oil, Calcium Gluconate, Silica, Potassium Sorbate, Phenoxyethanol, Ergothioneine

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.

3-O-Ethyl Ascorbic Acid is one of the most popular "stable" vitamin C derivatives in skincare.

Plain ascorbic acid is fantastic but notoriously fragile; it browns, oxidizes, and loses potency fast. So attaching an ethyl group to the third carbon of the molecule gives it some cool perks:

In a formula, it does the 3 classic vitamin C jobs: it acts as an antioxidant, helps brighten skin tone by inhibiting tyrosinase, and supports collagen.

The evidence is reasonably solid for a cosmetic ingredient; Liao and colleagues (2018) showed it's significantly more stable than ascorbic acid while still being effective.

A 2021 study by Zerbinati and colleagues tested a serum with 30% 3-O-ethyl-l-ascorbic acid and 1% lactic acid significantly increased collagen production, reduced UVB-induced DNA damage, and decreased melanin on a reconstructed pigmented skin model.

Typical real world usage sits around 0.5-5% (and 1-2% is common for daily serums).

Amounts up to 30% have been shown to be non-irritating on human skin samples, but two isolated cases reported allergic contact dermatitis so a patch test is sensible if you have reactive skin.

This ingredient is calcium salt of gluconic acid. It is a humectant, meaning it attracts water to your skin.

Ergothioneine is an amino acid found naturally in mushrooms, grains, and meat. It has antioxidant and skin soothing properties.

This amino acid helps with:

Maintaining DNA stability and cell reproduction

Enhances cellular immunity

Skin brightening

Anti-aging

Skin soothing

Gluconolactone is a PHA. PHAs are a great gentle alternative to traditional AHAs.

When applied, Gluconolactone has the same affect on skin as AHAs such as lactic acid. It helps dissolve the dead skin cells in the top layer of your skin. This improves texture and brightens the skin.

PHAs are more gentle than AHAs due to their larger structure. They do not penetrate as deeply as AHAs and take a longer time to dissolve dead cells. Studies show PHAs do not cause as much irritation.

Gluconolactone has some interesting properties:

In a 2004 study, Gluconolactone was found to prevent UV damage in mouse skin cells and has not been found to increase sun sensitivity. However, we still recommend wearing SPF daily.

This ingredient is is an created by reacting gluconic acid with an alcohol.

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.

Silica, also known as silicon dioxide, is a naturally occurring mineral. It is used as a fine, spherical, and porous powder in cosmetics.

Though it has exfoliant properties, the function of silica varies depending on the product.

The unique structure of silica enhances the spreadability and adds smoothness, making it a great texture enhancer.

It is also used as an active carrier, emulsifier, and mattifier due to its ability to absorb excess oil.

In some products, tiny microneedles called spicules are made from silica or hydrolyzed sponge. When you rub them in, they lightly polish away dead skin layers and enhance the penetration of active ingredients.

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.

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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