Versus

COSRX The Vitamin C 23 Serum Versus Sunday Riley C.E.O. 15% Vitamin C Brightening Serum

Serum
Serum
Korean Brand South Korea
American Brand United States

Updated on June 28, 2024

Overview

What they are

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

Cool Features

They both contain Vitamin C and Vitamin E

Suited For

They're both likely to be good for fighting acne, anti aging, dry skin, brightening skin, oily skin, reducing pores, scar healing, dark spots and better texture

Free From

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

What's Inside

They both contain oils

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

What's inside (and what isn't)

What's inside (and what isn't)

At a glance

Click on any of the items below to learn more

Key Ingredients

Benefits

Concerns

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

found in both products
The Vitamin C 23 Serum

Ingredients Explained

These ingredients are found in both products.

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

Skin Conditioning, Solvent

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. Stay hydrated!

Learn more about Water
Emollient, Skin Conditioning

Squalane is an emollient that helps the skin hold onto moisture. It's an oily liquid that occurs naturally in certain types of fish and plant oils.

Because squalane boosts hydration in the skin, it also comes with plenty of benefits: it is an antioxidant and can help fight free radicals and skin damage. Squalane is also found to have a detoxifying effect when applied.

Squalane comes from squalene, which occurs naturally within the sebum of our skin. It is one of the oils our skin produces to keep itself hydrated. Squalane is the hydrogenated version of squalene and has a longer shelf life.

Research shows that squalane is non-irritating (even at 100% concentration).

In general, it's a fantastic ingredient. It does a great job at hydrating the skin, and it's suitable for those with sensitive skin.

The source of squalane may impact malassezia / fungal acne. This is because olive oil derived squalane can contain impurities such as fatty acids and plant waxes. Sugarcane derived squalane is recommended for anyone with malassezia concerns.

Is squalane vegan?

This depends on the source. Squalane can be derived from both plants and animals. Most squalane used in skincare comes from plants.

Please note: the source of squalane is only known if disclosed by the brand. We recommend reaching out to the brand if you have any questions about their squalane.

Read more about squalene with an "e".

Is squalane an oil?

Squalane is often called an oil, but it’s technically not; it’s a hydrocarbon, meaning it’s only made of carbon and hydrogen, unlike true oils which are triglycerides made of fatty acids and glycerol.

The term “oil-free” isn’t regulated, so companies can define it however they want. Some exclude all oils, while others just avoid mineral oil or comedogenic oils.

While some people avoid oils thinking they cause breakouts, the right kind of oil (or oil-like ingredient like squalane) can actually help balance and hydrate your skin. It’s worth testing out simple oils or squalane to see what works best for your skin.

Learn more about Squalane
Antioxidant, Masking, Skin Conditioning

Tocopherol (also known as Vitamin E) is a common antioxidant used to help protect the skin from free-radicals and strengthen the skin barrier. It's also fat soluble - this means our skin is great at absorbing it.

Vitamin E also helps keep your natural skin lipids healthy. Your lipid skin barrier naturally consists of lipids, ceramides, and fatty acids. Vitamin E offers extra protection for your skin’s lipid barrier, keeping your skin healthy and nourished.

Another benefit is a bit of UV protection. Vitamin E helps reduce the damage caused by UVB rays. (It should not replace your sunscreen). Combining it with Vitamin C can decrease sunburned cells and hyperpigmentation after UV exposure.

You might have noticed Vitamin E + C often paired together. This is because it is great at stabilizing Vitamin C. Using the two together helps increase the effectiveness of both ingredients.

There are often claims that Vitamin E can reduce/prevent scarring, but these claims haven't been confirmed by scientific research.

Learn more about Tocopherol

When to use

608 Routines
76% use in am
24% use in pm
91% use every day
When to use See routines that use it ->
269 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

COSRX The Vitamin C 23 Serum 34 ingredients

3.5 /5
from 13 ratings
Works Well (5) Strong Scent (4) Absorbs Well (3)
laila.21's avatar

Laila

1 year ago
Review

I didn't like the consistency of this serum at all.
It felt like I was putting oil to my face, but since I always use the whole product to see results this did nothing to me other than feeling uncomfortable.

#oily
#strong scent
#works well
ChienYun_CY's avatar

Chien Yun Ang

2 years ago
Review

Cured my acne scars
I had mix feelings when I first bought this as I read that the smell can be off-putting. But I am glad I bought it. My acne scars faded a lot more after 3 days of using it and saw great results in one week. It also didn't break me out despite containing alcohols and oils. It does sting a little on the first application but doesn't irritate my skin. The smell can be quite strong Show more

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.