Versus

Allies of Skin 35% Vitamin C+ Perfecting Serum Versus Sunday Riley C.E.O. 15% Vitamin C Brightening Serum

Oil
Serum
American Brand United States
American Brand United States

Updated on July 18, 2023

Overview

What they are

These products are both cruelty-free and reef safe . They have a total of 3 ingredients in common

Cool Features

They both contain Vitamin C

Suited For

They're both likely to be good for anti aging, brightening skin, reducing pores, dark spots and better texture

Free From

They both do not contain any harsh alcohols, common allergens, parabens, silicones or sulfates

We independently verify ingredients, and our claims are backed by peer-reviewed research. Spot a product that needs an update? Let us know.

Ingredient Info

Click any item below to learn more and see relevant ingredients

About this product

About this product

At a glance

Click on any of the items below to learn more

Key Ingredients

Benefits

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

found in both products

Ingredients Explained

These ingredients are found in both products.

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

Antioxidant, Skin Conditioning

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:

Learn more about Tetrahexyldecyl Ascorbate
Emollient, Humectant, Skin Conditioning

Caprylyl Glycol is a humectant and emollient, meaning it attracts and preserves moisture.

It is a common ingredient in many products, especially those designed to hydrate skin. The primary benefits are retaining moisture, skin softening, and promoting a healthy skin barrier.

Though Caprylyl Glycol is an alcohol derived from fatty acids, it is not the kind that can dry out skin.

This ingredient is also used as a preservative to extend the life of products. It has slight antimicrobial properties.

Learn more about Caprylyl Glycol
Preservative

Phenoxyethanol is a preservative that has germicide, antimicrobial, and aromatic properties. Studies show that phenoxyethanol can prevent microbial growth. By itself, it has a scent that is similar to that of a rose.

It's often used in formulations along with Caprylyl Glycol to preserve the shelf life of products.

When to use

20 Routines
100% use in am
0% use in pm
100% use every day
263 Routines
89% use in am
11% use in pm
91% use every day
When to use See routines that use it ->

Reviews

Here's what our community thinks

Allies of Skin 35% Vitamin C+ Perfecting Serum 10 ingredients

35% Vitamin C+ Perfecting Serum hasn't been rated yet.
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Sunday Riley C.E.O. 15% Vitamin C Brightening Serum 22 ingredients

5.0 /5
from 1 rating
reneelovesherskin's avatar

reneelovesherskin

2 years ago
Review

my favorite serum
I wear this every morning, combined with the Sunday Riley C.E.O. face oil. It has a great citrus scent. I feel that it has contributed to lightening my dark spots and giving me a brighter complexion.