Allies of Skin 35% Vitamin C+ Perfecting Serum Versus SkinBetter Science Alto Defense Serum

Allies of Skin 35% Vitamin C+ Perfecting Serum Versus SkinBetter Science Alto Defense Serum

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

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

No concerns

Ingredients Side-by-side

Ethoxydiglycol

3-O-Ethyl Ascorbic Acid

Tetrahexyldecyl Ascorbate

Dimethyl Isosorbide

Isodecyl Neopentanoate

Glutathione

Superoxide Dismutase

Ethylhexylglycerin

Caprylyl Glycol

Phenoxyethanol

Ethoxydiglycol, 3-O-Ethyl Ascorbic Acid, Tetrahexyldecyl Ascorbate, Dimethyl Isosorbide, Isodecyl Neopentanoate, Glutathione, Superoxide Dismutase, Ethylhexylglycerin, Caprylyl Glycol, Phenoxyethanol

Water

Butylene Glycol

Propanediol

Ethylhexyl Olivate

Cetearyl Alcohol

Chlorogenic Acids

Hydrolyzed Sodium Hyaluronate

Lauryl Lactate

Glycyrrhiza Glabra Root Extract

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

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

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

Alternatives

Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

Dimethyl Isosorbide (often shortened to DMI) is a sugar-derived solvent made from sorbitol. It's used to dissolve tricky ingredients and help them mix smoothly into a formula.

Many actives sit as gritty crystals when undissolved, so DMI swoops in to full dissolve them. This helps improve texture, stability, and how evenly an active is distributed.

It does have a penetration-enhancing reputation that is a bit more nuanced than marketing suggests; a cell study on human skin found that 10% DMI didn't significantly boost the permeation of Hydroquinone, Salicylic Acid, or Octadecenedioic Acid compared to controls (though it did improve their solubility in the formula itself).

Typical usage concentrations usually range from 1-10% depending on the formula's needs; this ingredient is also well tolerated at these levels.

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.

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.

Superoxide Dismutase is found in all living cells. This ingredient is AKA as 'SOD'.

SOD is a strong antioxidant. It protects living cells against oxidative damage by breaking down radical molecules into regular oxygen and hydrogen peroxide.

Antioxidants help fight free-radical molecules that may damage your skin's DNA. This may help with the signs of aging. Due to its antioxidant property, it is used to help treat chronic inflammation.

In cosmetics, SOD is usually obtained from marine phytoplankton, bovine liver, horseradish, cantaloupe, and certain bacteria.

The three major families of SOD include: Copper/Zinc, Iron/Manganese, and Nickel.

When eating SOD-rich foods, our bodies break it down into amino acids before absorption. Foods that contain SOD include: melons, citrus, spinach, broccoli, kale, almonds, sunflower seeds, and blue-green algae.

Tetrahexyldecyl Ascorbate (THD) is a stable and oil-soluble form of Vitamin C.

THD is special in that it has the ability to travel deeper into skin than traditional ascorbic acid while maintaining the same skin benefits (double win!).

Because it’s oil-soluble, THD dives deep into your skin’s fatty layers (think ceramides and cholesterol) to fight off the kind of free radicals that mess with your skin barrier. This makes it a great pair with water-based vitamin C (ascorbic acid) that mainly works on the surface.

Even at just 0.1%, THD is already showing great antioxidant activity. When used up to 2%, it helps keep your skin happy and calm, especially when it’s stressed from pollution or sun.

Want to fade dark spots or tackle hyperpigmentation? You’ll want 5% or more. Pairing it with brightening buddies like niacinamide or licorice root gives even better results. One study even used 30% THD with other brighteners and saw real results on stubborn discoloration, even in melasma-prone skin.

A note on THD: It’s has a slightly silky, oily texture and usually shows up colorless or pale yellow (though the exact shade can vary by supplier).

While you can sneak it into water-based formulas, it really shines when paired with silicones or oils, which help your skin soak it up better.

THD is pretty stable, but it’s still vulnerable to degradation like ascorbic acid. Too much light or heat (above 113°F / 45°C) can break it down over time. Go for dark and opaque packaging that keeps it safe and shady!

Read more about other types of Vitamin C:

Similar Comparisons