Versus

CU Skin Clean-Up Vitamin C+ Serum Versus COSRX The Vitamin C 23 Serum

Serum
Serum
Korean Brand South Korea
Korean Brand South Korea

Updated on June 28, 2024

Overview

What they are

These products are both reef safe serums. They have a total of 5 ingredients in common

Cool Features

They both contain niacinamide and Vitamin C

Suited For

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

Free From

They both do not contain any common allergens, fragrances, parabens 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
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
Humectant, Masking, Skin Conditioning

Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

  • It is a solvent, meaning that it helps to dissolve other ingredients. This also enhances the absorption of the product into one's skin.
  • It is a humectant, which means that it helps attract moisture into the skin.
  • It helps improve product application.
  • It has mild preservative properties.

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

Masking, Skin Conditioning

Arginine is an amino acid that is important for human development. Your body uses is it to produce hair keratin and skin collagen.

As a cosmetic ingredient, Arginine has antioxidant properties and can also help repair damaged skin. This ingredient is derived either synthetically or from animals.

Arginine isn't fungal acne safe when used in the presence of other lipids (fats, fatty acids, oils, esters, etc). Oils and fats occur naturally within the skin, so take caution when using Arginine if you're prone to fungal acne.

Learn more about Arginine
Smoothing

Niacinamide is a multitasking form of vitamin B3 that strengthens the skin barrier, reduces pores and dark spots, regulates oil, and improves signs of aging.

And the best part? It's gentle and well-tolerated by most skin types, including sensitive and reactive skin.

You might have heard of "niacin flush", or the reddening of skin that causes itchiness. Niacinamide has not been found to cause this.

In very rare cases, some individuals may not be able to tolerate niacinamide at all or experience an allergic reaction to it.

If you are experiencing flaking, irritation, and dryness with this ingredient, be sure to double check all your products as this ingredient can be found in all categories of skincare.

When incorporating niacinamide into your routine, look out for concentration amounts. Typically, 5% niacinamide provides benefits such as fading dark spots. However, if you have sensitive skin, it is better to begin with a smaller concentration.

When you apply niacinamide to your skin, your body converts it into nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme that is already found in your cells as "fuel" and powers countless biological processes.

In your skin, NAD helps repair cell damage, produce new healthy cells, support collagen production, strengthen the skin barrier, and fight environmental stressors (like UV and pollution).

Our natural NAD levels start to decline with age, leading to slower skin repair, visible aging, and a weaker skin barrier. By providing your skin niacinamide, you're recharging your skin's NAD levels. This leads to stronger, healthier, and younger looking skin.

Another name for vitamin B3 is nicotinamide. This vitamin is water-soluble and our bodies don't store it. We obtain Vitamin B3 from either food or skincare. Meat, fish, wheat, yeast, and leafy greens contain vitamin B3.

The type of niacinamide used in skincare is synthetically created.

Learn more about Niacinamide
Antioxidant, Buffering, Masking

Ascorbic Acid is is pure Vitamin C. This form makes up the largest amount of vitamin C found naturally in our skin.

Not only is vitamin C great for your overall health and immune system, it also has plenty of benefits on your skin.

Vitamin C is best used for brightening skin. It improves dark spots, acne scars, and hyperpigmentation. This is because it blocks the process of skin darkening when exposed to UV.

Remember: Vitamin C should not replace sunscreen!

Your skin uses vitamin C to build collagen. Collagen is one key component in having a strong skin barrier and plump skin. Vitamin C also plays a role in regulating collagen, thus making it effective in improving wrinkles and fine lines.

Ascorbic acid shows potent antioxidant activity. As an antioxidant, it helps fight free-radicals. Free-radicals are molecules that may damage your skin cells. These antioxidants also protect skin against UV damage.

The best formulations include Vitamin E and/or ferulic acid. These two ingredients help stabilize and provide a boost in the benefits of ascorbic acid. This is because ascorbic acid becomes unstable when exposed to UV and air. In fact, you can tell your ascorbic acid has oxidized when it turns an orange-yellow color.

Ascorbic acid is generally compatible with other ingredients. However, using ascorbic acid with other active ingredients might cause irritation. Two ingredients: copper ions and benzoyl peroxide, will inactivate ascorbic acid completely.

Read more about other types of Vitamin C:

Foods rich with vitamin C include oranges, strawberries, broccoli, bell peppers, and more. When consuming Vitamin C, your skin receives a portion of the nutrients.

Learn more about Ascorbic Acid

When to use

1 Routine
0% use in am
100% use in pm
100% use every day
597 Routines
76% use in am
24% use in pm
92% use every day
When to use See routines that use it ->

Reviews

Here's what our community thinks

CU Skin Clean-Up Vitamin C+ Serum 19 ingredients

Clean-Up Vitamin C+ Serum hasn't been rated yet.
Rate it now

COSRX The Vitamin C 23 Serum 34 ingredients

3.7 /5
from 12 ratings
Works Well (5) Absorbs Well (3) Oily (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