First Aid Beauty 10% Vitamin C Brightening Serum Versus Glow Recipe Guava Vitamin C Dark Spot Treatment Serum

First Aid Beauty 10% Vitamin C Brightening Serum Versus Glow Recipe Guava Vitamin C Dark Spot Treatment Serum

This brightening serum is formulated around 3-O-Ethyl Ascorbic Acid and Colloidal Oatmeal to brighten dull-looking skin and calm redness.

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

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

3-O-Ethyl Ascorbic Acid

Squalane

Sodium Citrate

Tocopheryl Acetate

Colloidal Oatmeal

Chrysanthemum Parthenium Extract

Camellia Sinensis Leaf Extract

Glycyrrhiza Glabra Root Extract

Glycerin

Polyglyceryl-6 Polyricinoleate

Xanthan Gum

Polyglyceryl-10 Dioleate

Phenoxyethanol

Citric Acid

Sodium Benzoate

Potassium Sorbate

Sodium Hydroxide

Tetrasodium EDTA

Water, 3-O-Ethyl Ascorbic Acid, Squalane, Sodium Citrate, Tocopheryl Acetate, Colloidal Oatmeal, Chrysanthemum Parthenium Extract, Camellia Sinensis Leaf Extract, Glycyrrhiza Glabra Root Extract, Glycerin, Polyglyceryl-6 Polyricinoleate, Xanthan Gum, Polyglyceryl-10 Dioleate, Phenoxyethanol, Citric Acid, Sodium Benzoate, Potassium Sorbate, Sodium Hydroxide, Tetrasodium EDTA

Propanediol

C9-12 Alkane

Psidium Guajava Fruit Extract

Tetrahexyldecyl Ascorbate

Tranexamic Acid

Sodium Polyacryloyldimethyl Taurate

Ascorbyl Glucoside

Magnesium Ascorbyl Phosphate

Sodium Ascorbyl Phosphate

Psidium Guajava Seed Oil

Tocopherol

Sodium Hyaluronate

Ferulic Acid

Tremella Fuciformis Sporocarp Extract

Pyrus Malus Fruit Extract

Musa Sapientum Fruit Extract

Prunus Armeniaca Kernel Extract

Pyrus Communis Fruit Extract

Rubus Idaeus Fruit Extract

Melia Azadirachta Flower Extract

Melia Azadirachta Leaf Extract

Corallina Officinalis Extract

Coccinia Indica Fruit Extract

Hexanoyl Dipeptide-3 Norleucine Acetate

1,2-Hexanediol

Caprylic/Capric Triglyceride

Caprylyl Glycol

Hydroxyacetophenone

Sodium Stearoyl Glutamate

Coco-Caprylate/Caprate

Betaine

Lecithin

Polyglyceryl-10 Dipalmitate

Sodium Phytate

Decyl Glucoside

Lauryl Glucoside

Ethylhexylglycerin

Water, Propanediol, C9-12 Alkane, Psidium Guajava Fruit Extract, Tetrahexyldecyl Ascorbate, Tranexamic Acid, Sodium Polyacryloyldimethyl Taurate, 3-O-Ethyl Ascorbic Acid, Ascorbyl Glucoside, Magnesium Ascorbyl Phosphate, Sodium Ascorbyl Phosphate, Psidium Guajava Seed Oil, Tocopherol, Tocopheryl Acetate, Sodium Hyaluronate, Ferulic Acid, Tremella Fuciformis Sporocarp Extract, Pyrus Malus Fruit Extract, Musa Sapientum Fruit Extract, Prunus Armeniaca Kernel Extract, Pyrus Communis Fruit Extract, Rubus Idaeus Fruit Extract, Melia Azadirachta Flower Extract, Melia Azadirachta Leaf Extract, Corallina Officinalis Extract, Coccinia Indica Fruit Extract, Hexanoyl Dipeptide-3 Norleucine Acetate, Polyglyceryl-10 Dioleate, Glycerin, 1,2-Hexanediol, Caprylic/Capric Triglyceride, Caprylyl Glycol, Hydroxyacetophenone, Sodium Stearoyl Glutamate, Coco-Caprylate/Caprate, Betaine, Lecithin, Polyglyceryl-10 Dipalmitate, Sodium Citrate, Sodium Phytate, Potassium Sorbate, Decyl Glucoside, Lauryl Glucoside, Ethylhexylglycerin, Citric Acid, Xanthan Gum, Phenoxyethanol

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.

Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.

Like other AHAs, citric acid can exfoliate skin by breaking down the bonds that hold dead skin cells together. This helps reveal smoother and brighter skin underneath.

However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.

Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.

In skincare formulas, citric acid can:

While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.

Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.

Rosacea skin has a lower threshold for acids generally, with 62.5% of rosacea subjects in one study reacting to lactic acid in a sting test. This is why we mark citric acid as a potential rosacea trigger.

However, this ingredient shows up as a pH adjuster or chelator at roughly 0.1-1% in many products. These low levels are unlikely to be an issue for rosacea skin and becomes a potential trigger at exfoliating concentrations (20%). Because everybody's skin is unique, we recommend a patch test if you are unsure.

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.

Polyglyceryl-10 Dioleate isn't fungal acne safe.

Potassium Sorbate is a preservative used to prevent yeast and mold in products. It is commonly found in both cosmetic and food products.

This ingredient comes from potassium salt derived from sorbic acid. Sorbic acid is a natural antibiotic and effective against fungus.

Both potassium sorbate and sorbic acid can be found in baked goods, cheeses, dried meats, dried fruit, ice cream, pickles, wine, yogurt, and more.

You'll often find this ingredient used with other preservatives.

Sodium Citrate is the sodium salts of citric acid. In skincare, it is used to alter pH levels and acts as a preservative.

Its main functions are to maintain the pH of a product and neutralize metal ions.

The acidity of our skin is maintained by our glands and skin biome; normal pH level of skin is slightly acidic (~4.75-5.5).

Being slightly acidic allows our skin to create an "acid mantle". This acid mantle is a thin barrier that protects our skin from bacteria and contaminants.

Tocopheryl Acetate is a stable, shelf-friendly form of vitamin E.

Formulators love it because plain vitamin E oxidizes quickly once it hits air. This acetate version stays stable and resists going off, helping to extend a product's shelf life.

It's actually inactive on its own and works like a slow-release "storage" form; the enzymes in your skin called esterases gradually convert it into active vitamin E over time.

One in vivo study showed 5% of the acetate in the living layer of the epidermis converted to vitamin E after 5 days of application. This study also found the skin gained protection against UV damage even though the conversion was slow and small.

Once converted, vitamin E acts as a skin's main fat-soluble antioxidant that fights free radicals to protect skin from damage.

Topical vitamin E generally boosts the skin's photoprotection, and it reduced UV-damage in animal models.

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.

Overall, it has a pretty solid safety profile and has been found to be non-irritating and non-comedogenic. Allergic reactions may happen but stay rare due to how widely the ingredient gets used.

The concentration will vary depending on the formula; industry data shows 0.1% in baby lotions, 3% in lipsticks, and 5% in foot powders. You can also find this ingredient at 100% in a pure vitamin E oil.

Most leave-on skincare keeps it at the lower end, often between 0.5-1%.

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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