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Kiehl's Powerful-Strength Vitamin C Serum Versus Summer Fridays CC Me Vitamin C Serum

Kiehl's Powerful-Strength Vitamin C Serum Versus Summer Fridays CC Me Vitamin C Serum 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 serum is formu

Written by Peptide Therapy Guide Editorial Team
For education only

This guide cannot diagnose a condition or recommend a personal treatment plan. Discuss medical questions with a qualified professional.

Kiehl's Powerful-Strength Vitamin C Serum Versus Summer Fridays CC Me Vitamin C Serum

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

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

Niacinamide

Butylene Glycol

3-O-Ethyl Ascorbic Acid

Capryloyl Glycerin/Sebacic Acid Copolymer

Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer

Squalane

Sodium Citrate

Phenoxyethanol

Sodium Hydroxide

Citric Acid

Diheptyl Succinate

Tocopheryl Acetate

Xanthan Gum

Tetrasodium Glutamate Diacetate

Carbomer

Polysorbate 20

Palmitoyl Oligopeptide

Palmitoyl Tetrapeptide-7

Camellia Oleifera Leaf Extract

Ethylhexylglycerin

Orchis Mascula Flower Extract

Caprylic/Capric Triglyceride

Cananga Odorata Flower Extract

Cucumis Melo Cantalupensis Fruit Extract

Eugenia Caryophyllus Flower Extract

Glycine Soja Oil

Pyrus Malus Fruit Extract

Prunus Armeniaca Fruit Extract

Rosa Gallica Flower Extract

Cinnamomum Cassia Bark Extract

Jasminum Officinale Flower/Leaf Extract

Coffea Arabica Leaf/Seed Extract

Camellia Sinensis Leaf Extract

Amyl Cinnamal

Cinnamyl Alcohol

Citronellol

Eugenol

Hydroxycitronellal

Water, Niacinamide, Butylene Glycol, 3-O-Ethyl Ascorbic Acid, Ascorbyl Glucoside, Glycerin, Capryloyl Glycerin/Sebacic Acid Copolymer, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Squalane, Sodium Citrate, Phenoxyethanol, Sodium Hydroxide, Citric Acid, Diheptyl Succinate, Tocopheryl Acetate, Xanthan Gum, Tetrasodium Glutamate Diacetate, Carbomer, Polysorbate 20, Palmitoyl Oligopeptide, Palmitoyl Tetrapeptide-7, Camellia Oleifera Leaf Extract, Ethylhexylglycerin, Orchis Mascula Flower Extract, Caprylic/Capric Triglyceride, Cananga Odorata Flower Extract, Cucumis Melo Cantalupensis Fruit Extract, Eugenia Caryophyllus Flower Extract, Glycine Soja Oil, Pyrus Malus Fruit Extract, Prunus Armeniaca Fruit Extract, Rosa Gallica Flower Extract, Cinnamomum Cassia Bark Extract, Jasminum Officinale Flower/Leaf Extract, Coffea Arabica Leaf/Seed Extract, Camellia Sinensis Leaf Extract, Amyl Cinnamal, Cinnamyl Alcohol, Citronellol, Eugenol, Hydroxycitronellal

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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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Peptide Therapy Guide Editorial Team

Editorial team for Peptide Therapy Guide.

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