Skin science article
Dr. Althea Vitamin C Boosting Serum Versus Paula's Choice 25% Vitamin C + Glutathione Clinical Serum
Dr. Althea Vitamin C Boosting Serum Versus Paula's Choice 25% Vitamin C + Glutathione Clinical Serum This brightening serum is formulated around Niacinamide and Tranexamic Acid to brighten dull-looking skin and fade the look of dark spots. This brightening ser
Dr. Althea Vitamin C Boosting Serum Versus Paula's Choice 25% Vitamin C + Glutathione Clinical Serum
This brightening serum is formulated around Niacinamide and Tranexamic Acid to brighten dull-looking skin and fade the look of dark spots.
This brightening serum is formulated around Tetrahexyldecyl Ascorbate and Ascorbyl Glucoside to brighten dull-looking skin and fade the look of dark spots.
What's inside
Key Ingredients
Benefits
Concerns
No concerns
Ingredients Side-by-side
Hippophae Rhamnoides Water
Centella Asiatica Leaf Water
Niacinamide
Butylene Glycol
1,2-Hexanediol
Dipropylene Glycol
Water
Methyl Gluceth-20
Methylpropanediol
Betaine
Tranexamic Acid
Glycerin
Pentylene Glycol
Propanediol
Hydroxyethyl Urea
Laminaria Japonica Extract
Eclipta Prostrata Leaf Extract
Ficus Carica Fruit Extract
Centella Asiatica Extract
Hydrogenated Lecithin
Sodium Hyaluronate
Carbomer
3-O-Ethyl Ascorbic Acid
C12-14 Pareth-12
Ammonium Acryloyldimethyltaurate/Vp Copolymer
Xanthan Gum
Tromethamine
Panthenol
Ethylhexylglycerin
Adenosine
Disodium EDTA
Fructooligosaccharides
Beta-Glucan
Ascorbic Acid
Hydrolyzed Hyaluronic Acid
Ceramide NP
Alpha-Arbutin
Tocopherol
Bifida Ferment Lysate
Bisabolol
Ubiquinone
Hydroxydecyl Ubiquinone
Sodium Acetylated Hyaluronate
Hippophae Rhamnoides Water, Centella Asiatica Leaf Water, Niacinamide, Butylene Glycol, 1,2-Hexanediol, Dipropylene Glycol, Water, Methyl Gluceth-20, Methylpropanediol, Betaine, Tranexamic Acid, Glycerin, Pentylene Glycol, Propanediol, Hydroxyethyl Urea, Laminaria Japonica Extract, Eclipta Prostrata Leaf Extract, Ficus Carica Fruit Extract, Centella Asiatica Extract, Hydrogenated Lecithin, Sodium Hyaluronate, Carbomer, 3-O-Ethyl Ascorbic Acid, C12-14 Pareth-12, Ammonium Acryloyldimethyltaurate/Vp Copolymer, Xanthan Gum, Tromethamine, Panthenol, Ethylhexylglycerin, Adenosine, Disodium EDTA, Fructooligosaccharides, Beta-Glucan, Ascorbic Acid, Hydrolyzed Hyaluronic Acid, Ceramide NP, Alpha-Arbutin, Tocopherol, Bifida Ferment Lysate, Bisabolol, Ubiquinone, Hydroxydecyl Ubiquinone, Sodium Acetylated Hyaluronate
Tetrahexyldecyl Ascorbate
Dimethicone
C9-12 Alkane
Ascorbyl Glucoside
Silica
Pyrus Malus Fruit Extract
Polyglyceryl-6 Polyricinoleate
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
Oryza Sativa Bran Extract
Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
Cetyl Alcohol
Caprylyl Glycol
Lysine Carboxymethyl Cysteinate
Coco-Caprylate/Caprate
Glutathione
Sodium Citrate
Sodium Phytate
Hexylene Glycol
Helianthus Annuus Seed Extract
Urea
Mannitol
Caprylic/Capric Triglyceride
Sodium PCA
Rosmarinus Officinalis Leaf Extract
Polysorbate 60
Sorbitan Isostearate
Trehalose
Glucose
Vanilla Planifolia Fruit Extract
Polyquaternium-51
Ergothioneine
Triacetin
Phenoxyethanol
Water, Tetrahexyldecyl Ascorbate, Dimethicone, Glycerin, C9-12 Alkane, Ascorbyl Glucoside, Silica, Pyrus Malus Fruit Extract, Hydrogenated Lecithin, Polyglyceryl-6 Polyricinoleate, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Xanthan Gum, Oryza Sativa Bran Extract, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Cetyl Alcohol, Caprylyl Glycol, Lysine Carboxymethyl Cysteinate, Coco-Caprylate/Caprate, Tocopherol, Glutathione, Sodium Citrate, Sodium Phytate, Hexylene Glycol, Ethylhexylglycerin, Helianthus Annuus Seed Extract, Urea, Mannitol, Caprylic/Capric Triglyceride, Sodium PCA, Rosmarinus Officinalis Leaf Extract, Polysorbate 60, Sorbitan Isostearate, Trehalose, Ascorbic Acid, Glucose, Vanilla Planifolia Fruit Extract, Polyquaternium-51, Ergothioneine, Triacetin, Sodium Hyaluronate, 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.
Ascorbic Acid is is pure Vitamin C and is the biologically active form used directly by skin.
Not only is vitamin C great for your overall health and immune system, but it also has plenty of benefits for your skin. It is best supported by academic literature for:
Topical vitamin C has been shown to help neutralize oxidative stress from UV and pollution, helping to improve photoaging and hyperpigmentation when used consistently.
One clinical study found that using 5% topical vitamin C for six months improved signs of photodamaged skin, both on the surface and in the deeper structural layers of the skin.
While vitamin C doesn’t replace sunscreen, studies show it can boost photoprotection when combined with Vitamin E and ferulic acid. These two ingredients help improve stability and protective effects.
The big downside of this ingredient is formulation difficulty. Vitamin C is prone to oxidation and doesn't penetrate the skin unless formulated correctly. Research found that vitamin C absorbs into the skin best at a low pH (< 3.5) with about 20% being the upper limit for effective absorption.
Skin levels can saturate after repeated application; this means your skin won’t keep absorbing more once it’s full of vitamin C. This is why more isn’t always better with vitamin C and why very high concentrations don’t necessarily give extra benefits.
Ascorbic acid generally works well with many skincare ingredients but can be irritating when combined with other active ingredients. Strong oxidizing acne treatments like benzoyl peroxide can reduce the effectiveness of vitamin C if they are used at the same time; they are often recommended for use at different times of day.
Read more about other types of Vitamin C:
Foods rich with vitamin C include oranges, strawberries, broccoli, bell peppers, and more. When consuming Vitamin C, your skin receives a portion of the nutrients.
Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.
Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.
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.
Hydrogenated Lecithin is a more stable version of lecithin.
It's made by taking lecithin (a phospholipid commonly found in soybeans and egg yolks) and hydrogenating it. This just means the unsaturated fatty acids are turned into saturated ones so they don't go bad as easily.
This ingredient is an emollient, emulsifier, and penetration enhancer. As an emollient, it helps soften and hydrate skin by trapping moisture within. As an emulsifier, it prevents oil and water ingredients from separating.
Hydrogenated Lecithin can form tiny spherical structures made of phospholipid bilayers called liposomes. These liposomes are able to capture compounds inside their structure and deliver them through the skin barrier.
Because phospholipids are a natural component of our cell membranes, this ingredient is inherently compatible with skin.
A 2021 study found lecithin-based surfactants were less harsh and more tolerable comared to Sodium Lauryl Sulfate (SLS).
Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.
In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.
Interestingly, the size of the molecule affects its behavior:
Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.
Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.
You'll typically see concentrations between 0.1-2% for this ingredient.
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.