Kiehl's Powerful-Strength Vitamin C Serum Versus Paula's Choice C5 Super Boost Eye Cream

Kiehl's Powerful-Strength Vitamin C Serum Versus Paula's Choice C5 Super Boost Eye Cream

This anti-aging serum is formulated around Ascorbic Acid and Ascorbyl Glucoside to soften the look of wrinkles and brighten dull-looking skin.

This brightening eye moisturizer is formulated around Ascorbyl Glucoside and 3-O-Ethyl Ascorbic Acid to brighten dull-looking skin and soften the look of wrinkles.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Propylene Glycol

Dimethicone

Glycerin

Ascorbic Acid

Ethylhexyl Palmitate

Cetyl PEG/PPG-10/1 Dimethicone

Dimethicone Crosspolymer

Ascorbyl Glucoside

Cyclohexasiloxane

Hydroxyethylpiperazine Ethane Sulfonic Acid

Lauroyl Lysine

Acrylonitrile/Methyl Methacrylate/Vinylidene Chloride Copolymer

Polysilicone-11

Adenosine

Hydrolyzed Hyaluronic Acid

Limonene

Isobutane

Citrus Aurantium Dulcis Peel Oil

Citrus Limon Peel Oil

Citral

Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate

Propylene Glycol, Dimethicone, Glycerin, Ascorbic Acid, Ethylhexyl Palmitate, Cetyl PEG/PPG-10/1 Dimethicone, Dimethicone Crosspolymer, Ascorbyl Glucoside, Cyclohexasiloxane, Hydroxyethylpiperazine Ethane Sulfonic Acid, Lauroyl Lysine, Acrylonitrile/Methyl Methacrylate/Vinylidene Chloride Copolymer, Polysilicone-11, Adenosine, Hydrolyzed Hyaluronic Acid, Limonene, Isobutane, Citrus Aurantium Dulcis Peel Oil, Citrus Limon Peel Oil, Citral, Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate

Water

Dicaprylyl Carbonate

Triheptanoin

3-O-Ethyl Ascorbic Acid

Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer

Arachidyl Alcohol

Cetearyl Alcohol

C13-15 Alkane

Ascorbyl Palmitate

Sh-Polypeptide-121

Acetyl Hexapeptide-8

Hyaluronic Acid

Zerumbone

Bacillus Ferment

Tocopherol

Tocopheryl Acetate

Butyrospermum Parkii Butter Unsaponifiables

Oryza Sativa Bran Extract

Rosmarinus Officinalis Leaf Extract

Helianthus Annuus Seed Oil

Helianthus Annuus Seed Extract

Hydrogenated Lecithin

Cetearyl Olivate

Sorbitan Olivate

Behenyl Alcohol

Arachidyl Glucoside

Propanediol

Butylene Glycol

Cetyl Alcohol

Sodium Phytate

Sodium Citrate

Citric Acid

Sodium Metabisulfite

Phenoxyethanol

Caprylyl Glycol

Ethylhexylglycerin

Hexylene Glycol

Sodium Hydroxide

Water, Dicaprylyl Carbonate, Glycerin, Triheptanoin, Ascorbyl Glucoside, 3-O-Ethyl Ascorbic Acid, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Arachidyl Alcohol, Cetearyl Alcohol, C13-15 Alkane, Ascorbyl Palmitate, Sh-Polypeptide-121, Acetyl Hexapeptide-8, Hyaluronic Acid, Zerumbone, Bacillus Ferment, Tocopherol, Tocopheryl Acetate, Butyrospermum Parkii Butter Unsaponifiables, Oryza Sativa Bran Extract, Rosmarinus Officinalis Leaf Extract, Helianthus Annuus Seed Oil, Helianthus Annuus Seed Extract, Hydrogenated Lecithin, Cetearyl Olivate, Sorbitan Olivate, Behenyl Alcohol, Arachidyl Glucoside, Propanediol, Butylene Glycol, Cetyl Alcohol, Sodium Phytate, Sodium Citrate, Citric Acid, Sodium Metabisulfite, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin, Hexylene Glycol, Sodium Hydroxide

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.

Ascorbyl Glucoside (AA-2G) is one of the most stable vitamin C derivatives out there.

It's made by attaching a glucose molecule to ascorbic acid; this glucose "cap" shields the vitamin C from air, light, heat, and metal ions that normally cause pure ascorbic acid to oxidize.

Once on your skin, the enzyme alpha-glucosidase snips off the glucose and gradually releases active ascorbic acid right where it's needed. Basically, it behaves like a slow-release pro-vitamin C with less of a stinging that high-strength ascorbic acid can cause.

The research supports the classic vitamin C benefits as well. In lab and human studies, AA-2G slowed down the skin's production of melanin (the pigment behind dark spots) and helped shield skin cells against sun damage better than ascorbyl phosphate.

These studies also showed AA-2G released vitamin C over a longer period.

A frequently cited manufacturer trial found that a 2% AA-2G face cream significantly improved wrinkle depth and skin roughness after 45 days.

And in 2009, a clinical trial showed it meaningfully lightened dark patches on the gums compared to a placebo.

There's also collagen-synthesis support (since vitamin C is a required cofactor for that) and an antioxidant effect too.

Typical usage is usually between 0.5-5% and most studies/products land around 2%.

AA-2G performs best when formulated at a mildly acidic pH (~5-7) which is much gentler than the pH that pure vitamin C demands (~2.5-3.5).

Just one thing worth knowing: the in-skin conversation rate is only about 55-60% by weight. So a 5% AA-2G product delivers roughly 2.75-3% of actual active vitamin C. On top of that, skin absorption is relatively low because the ingredient is water-soluble.

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.

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