Skin science article
Paula's Choice Resist Super Antioxidant Serum Versus Naturium Vitamin C Super Serum Plus
Paula's Choice Resist Super Antioxidant Serum Versus Naturium Vitamin C Super Serum Plus This anti-aging serum is formulated around Tetrahexyldecyl Ascorbate and Palmitoyl Tripeptide-5 to soften the look of wrinkles and brighten dull-looking skin. This brighte
Paula's Choice Resist Super Antioxidant Serum Versus Naturium Vitamin C Super Serum Plus
This anti-aging serum is formulated around Tetrahexyldecyl Ascorbate and Palmitoyl Tripeptide-5 to soften the look of wrinkles and brighten dull-looking skin.
This brightening serum is formulated around Niacinamide and Ascorbic Acid to brighten dull-looking skin and soften the look of wrinkles.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Cyclopentasiloxane
Dimethicone
Tetrahexyldecyl Ascorbate
Palmitoyl Tripeptide-5
Ceramide NP
Tocotrienols
Tocopherol
Ubiquinone
Thioctic Acid
Tocopheryl Acetate
Magnesium Ascorbyl Phosphate
Ferulic Acid
Beta-Glucan
Superoxide Dismutase
Epigallocatechin Gallate
Ergothioneine
Glutathione
Xanthophylls
Glycine Soja Seed Extract
Glycerin
Arctostaphylos Uva Ursi Leaf Extract
Lupinus Albus Seed Extract
Curcuma Longa Root
Elaeis Guineensis Oil
Phenoxyethanol
Cyclopentasiloxane, Dimethicone, Tetrahexyldecyl Ascorbate, Palmitoyl Tripeptide-5, Ceramide NP, Tocotrienols, Tocopherol, Ubiquinone, Thioctic Acid, Tocopheryl Acetate, Magnesium Ascorbyl Phosphate, Ferulic Acid, Beta-Glucan, Superoxide Dismutase, Epigallocatechin Gallate, Ergothioneine, Glutathione, Xanthophylls, Glycine Soja Seed Extract, Glycerin, Arctostaphylos Uva Ursi Leaf Extract, Lupinus Albus Seed Extract, Curcuma Longa Root, Elaeis Guineensis Oil, Phenoxyethanol
Water
Niacinamide
Propanediol
Ascorbic Acid
Aloe Barbadensis Leaf Juice
Retinol
Sodium Hyaluronate
Caprylyl Glycol
Hydroxyethylcellulose
Carbomer
Salicylic Acid
Humulus Lupulus Extract
Glyceryl Polyacrylate
Potassium Sorbate
Copernicia Cerifera Wax
Hexylene Glycol
Sorbitol
Sodium Hydroxide
Sorbitan Oleate
Acrylamide/Sodium Acryloyldimethyltaurate Copolymer
Helianthus Annuus Seed Oil
Isohexadecane
Polysorbate 80
Polysorbate 20
1,2-Hexanediol
Amylopectin
Dextrin
Polydextrose
Disodium Cocoamphodiacetate
Xanthan Gum
Citric Acid
Sodium Benzoate
Disodium Phosphate
Gold
Polysorbate 60
Ethyl Ferulate
Sodium Phosphate
Water, Niacinamide, Propanediol, Glycerin, Ascorbic Acid, Glutathione, Aloe Barbadensis Leaf Juice, Retinol, Sodium Hyaluronate, Caprylyl Glycol, Hydroxyethylcellulose, Carbomer, Salicylic Acid, Tocopheryl Acetate, Humulus Lupulus Extract, Glyceryl Polyacrylate, Potassium Sorbate, Copernicia Cerifera Wax, Hexylene Glycol, Sorbitol, Sodium Hydroxide, Sorbitan Oleate, Acrylamide/Sodium Acryloyldimethyltaurate Copolymer, Helianthus Annuus Seed Oil, Phenoxyethanol, Isohexadecane, Polysorbate 80, Polysorbate 20, 1,2-Hexanediol, Amylopectin, Dextrin, Polydextrose, Disodium Cocoamphodiacetate, Xanthan Gum, Tocopherol, Citric Acid, Sodium Benzoate, Disodium Phosphate, Gold, Polysorbate 60, Ethyl Ferulate, Sodium Phosphate
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.
Glutathione is a tiny protein-like molecule (a "tripeptide" build from 3 amino acids: glycine, cysteine, and glutamic acid) that your body already makes on its own.
Inside your body, it acts as one of the skin's main antioxidants that help fight against free radicals.
In skincare, it's best known as a brightening ingredient that slows down tyrosinase, the key enzyme that makes skin pigment. It also nudges the skin toward making a lighter type of pigment instead of a darker one.
This is why you'll see it in products aimed at dark spots and uneven tone.
A small number of real human trials have found a topical glutathione lotion:
The honest caveat is that the current evidence is still thin (few studies, small groups, short timelines). Glutathione also doesn't absorb into skin very easily so results tend to be modest and fade if you stop using it.
One thing worth clearing up:
The scary side effects you may have heard about come from glutathione injected intravenously, which has real safety concerns. Applying it topically is a completely different thing and has a clean track record.
Most human studies used it around 2% (as Glutathione or Glutathione Disulfide) and a 2% oxidized glutathione lotion and a 2% S-acyl glutathione cream are the concentrations with actual clinical data behind them.
There's no established "ideal" percentage yet but 1-2% is the evidence-backed range.
Allergy-wise, there is very low risk for this ingredient; it was well-tolerated across the topical trials. Only one participant had mild temporary redness that cleared up on its own and another study reported no adverse reactions at all.
One trial had ~10% of users drop out for irritation was using a combination cream that also had 10% azelaic acid so the irritation likely wasn't from the glutathione. There's no notable contact-allergy signal for topical glutathione in the literature but patch-testing before first use is still sensible for those with sensitive skin.
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.
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.
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.
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%.