Paula's Choice C15 Super Booster Versus SkinBetter Science Alto Defense Serum

Paula's Choice C15 Super Booster Versus SkinBetter Science Alto Defense Serum

This brightening serum is formulated around Ascorbic Acid and Ferulic Acid to brighten dull-looking skin and soften the look of wrinkles.

This calming serum is formulated around Glycyrrhiza Glabra Root Extract and Tetrahexyldecyl Ascorbate to calm redness and brighten dull-looking skin.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Ascorbic Acid

Dipropylene Glycol

Propanediol

Glycerin

Ethoxydiglycol

Sodium Hydroxide

PPG-26-Buteth-26

PEG-40 Hydrogenated Castor Oil

Bisabolol

Ferulic Acid

Sodium Phytate

Decylene Glycol

Tocopherol

1,2-Hexanediol

Sphingomonas Ferment Extract

Phenoxyethanol

Water, Ascorbic Acid, Dipropylene Glycol, Propanediol, Glycerin, Ethoxydiglycol, Sodium Hydroxide, PPG-26-Buteth-26, PEG-40 Hydrogenated Castor Oil, Bisabolol, Ferulic Acid, Sodium Phytate, Decylene Glycol, Tocopherol, 1,2-Hexanediol, Sphingomonas Ferment Extract, Phenoxyethanol

Butylene Glycol

Ethylhexyl Olivate

Cetearyl Alcohol

Chlorogenic Acids

Hydrolyzed Sodium Hyaluronate

Lauryl Lactate

Dimethyl Isosorbide

Glycyrrhiza Glabra Root Extract

Tetrahexyldecyl Ascorbate

Ergothioneine

Benzylidene Dimethoxydimethylindanone

Arabidopsis Thaliana Extract

Carnosine

Camellia Sinensis Leaf Extract

Vitis Vinifera Seed Extract

Theobroma Cacao Seed Extract

Curcuma Longa Root Extract

Olea Europaea Fruit Extract

Euterpe Oleracea Fruit Extract

Trifluoroacetyl Tripeptide-2

Buddleja Officinalis Flower Extract

Coffea Arabica Leaf Cell Extract

Crocus Sativus Leaf Cell Culture Extract

Superoxide Dismutase

Ubiquinone

Zingiber Officinale Root Extract

Ceramide NP

Ceramide AP

Ceramide EOP

Linoleic Acid

Linolenic Acid

Sea Whip Extract

Tocopheryl Acetate

Cholesterol

Phytosphingosine

Jojoba Esters

Sodium PCA

Pentylene Glycol

Methyl Gluceth-20

Helianthus Annuus Seed Wax

Acacia Decurrens Flower Wax

Lecithin

Sodium Lauroyl Lactylate

Dicetyl Phosphate

Propanediol Dicaprylate/Caprate

Polyglycerin-3

Ceteth-20 Phosphate

Diisostearyl Malate

Xanthan Gum

Steareth-2

Acacia Senegal Gum

Carbomer

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Dextran

Citric Acid

Disodium EDTA

Ethylhexylglycerin

Water, Butylene Glycol, Propanediol, Ethylhexyl Olivate, Cetearyl Alcohol, Chlorogenic Acids, Hydrolyzed Sodium Hyaluronate, Lauryl Lactate, Dimethyl Isosorbide, Glycyrrhiza Glabra Root Extract, Tetrahexyldecyl Ascorbate, Ergothioneine, Benzylidene Dimethoxydimethylindanone, Arabidopsis Thaliana Extract, Carnosine, Camellia Sinensis Leaf Extract, Vitis Vinifera Seed Extract, Theobroma Cacao Seed Extract, Curcuma Longa Root Extract, Olea Europaea Fruit Extract, Euterpe Oleracea Fruit Extract, Trifluoroacetyl Tripeptide-2, Buddleja Officinalis Flower Extract, Coffea Arabica Leaf Cell Extract, Crocus Sativus Leaf Cell Culture Extract, Superoxide Dismutase, Ubiquinone, Zingiber Officinale Root Extract, Ceramide NP, Ceramide AP, Ceramide EOP, Linoleic Acid, Linolenic Acid, Sea Whip Extract, Bisabolol, Tocopherol, Tocopheryl Acetate, Cholesterol, Phytosphingosine, Jojoba Esters, Sodium PCA, Pentylene Glycol, Methyl Gluceth-20, Glycerin, Helianthus Annuus Seed Wax, Acacia Decurrens Flower Wax, Lecithin, Sodium Lauroyl Lactylate, Dicetyl Phosphate, Propanediol Dicaprylate/Caprate, Polyglycerin-3, Ceteth-20 Phosphate, Diisostearyl Malate, Xanthan Gum, Steareth-2, Acacia Senegal Gum, Carbomer, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Dextran, Sodium Hydroxide, Citric Acid, Disodium EDTA, Ethylhexylglycerin, Phenoxyethanol

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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.

Bisabolol is a gentle skin conditioner, antioxidant, and soothing ingredient.

It's primary claim to fame is soothing and research shows topically applied bisabolol can quiet the chemical messengers that cause your skin to become inflamed, helping to sooth any irritation.

A clinical study found that applying 0.5% bisabolol daily for 8 weeks produced an average 9% decrease in skin pigmentation. Researchers found it can also suppress the process that leads to excess melanin production in skin.

In vitro studies found that bisabolol combined with propylene glycol significantly increased skin permeability by increasing lipid fluidity in the stratum corneum.

You'll likely see use concentrations quite low, usually 0.1-0.2%.

Overall, this is a well-tolerated ingredient that works well in formulas designed for sensitive, reactive, or post-procedure 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.

Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.

It’s often used to:

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

Sodium Hydroxide is also known as lye or caustic soda. It is used to adjust the pH of products; many ingredients require a specific pH to be effective.

In small amounts, sodium hydroxide is considered safe to use. However, large amounts may cause chemical burns due to its high alkaline.

Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.

"Alkaline" refers to a high pH level. A low pH level would be considered acidic.

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!

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