Versus

Cos De BAHA Vitamin C Serum Ascorbic Acid 15% Versus Numbuzin No.5 Vitamin Concentrated Serum

Serum
Serum
Korean Brand South Korea
Korean Brand South Korea

Updated on April 08, 2025

Overview

What they are

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

Cool Features

They both contain hyaluronic acid and Vitamin C

Suited For

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

Free From

They both do not contain any harsh alcohols, common allergens, oils, 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
No.5 Vitamin Concentrated Serum

Water

Skin Conditioning

Butylene Glycol

Humectant
1 / 0 Helps hydrate Dry Skin Icon

Niacinamide

Smoothing
Niacinamide IconGood for Oily Skin IconHelps reduce Skin Redness IconHelps reduce irritation IconGood for Minimizing Pores IconHelps with Anti-Aging IconGood for Dark Spots IconGood for Scar Healing IconHelps fight Acne IconHelps brighten skin Icon

Panthenol

Skin Conditioning
0 / 0 Helps hydrate Dry Skin IconHelps reduce Skin Redness IconHelps reduce irritation Icon

Tranexamic Acid

Astringent
Good for Dark Spots IconGood for Scar Healing Icon

Ingredients Explained

These ingredients are found in both products.

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

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
Skin Conditioning, Solvent

1,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse. 

It is a:

  • Humectant, drawing moisture into the skin
  • Emollient, helping to soften skin
  • Solvent, dispersing and stabilizing formulas
  • Preservative booster, enhancing the antimicrobial activity of other preservatives 
Humectant, Skin Conditioning

Sodium Hyaluronate is hyaluronic acid's salt form. It is commonly derived from the sodium salt of hyaluronic acid.

Like hyaluronic acid, it is great at holding water and acts as a humectant. This makes it a great skin hydrating ingredient.

Sodium Hyaluronate is naturally occurring in our bodies and is mostly found in eye fluid and joints.

These are some other common types of Hyaluronic Acid:

Learn more about Sodium Hyaluronate
Skin Conditioning

Panthenol is a common ingredient that helps hydrate and soothe the skin. It is found naturally in our skin and hair.

There are two forms of panthenol: D and L.

D-panthenol is also known as dexpanthenol. Most cosmetics use dexpanthenol or a mixture of D and L-panthenol.

Panthenol is famous due to its ability to go deeper into the skin's layers. Using this ingredient has numerous pros (and no cons):

Like hyaluronic acid, panthenol is a humectant. Humectants are able to bind and hold large amounts of water to keep skin hydrated.

This ingredient works well for wound healing. It works by increasing tissue in the wound and helps close open wounds.

Once oxidized, panthenol converts to pantothenic acid. Panthothenic acid is found in all living cells.

This ingredient is also referred to as pro-vitamin B5.

Learn more about Panthenol

Disodium EDTA plays a role in making products more stable by aiding other preservatives.

It is a chelating agent, meaning it neutralizes metal ions that may be found in a product.

Disodium EDTA is a salt of edetic acid and is found to be safe in cosmetic ingredients.

Learn more about Disodium EDTA

When to use

64 Routines
81% use in am
19% use in pm
95% use every day
When to use See routines that use it ->
911 Routines
66% use in am
34% use in pm
88% use every day
When to use See routines that use it ->

Reviews

Here's what our community thinks

Cos De BAHA Vitamin C Serum Ascorbic Acid 15% 14 ingredients

3.0 /5
from 1 rating
Doesn't Work (1)
Luta's avatar

Luta

1 month ago
Review

Didn't see any changes on my dark spots and it doesn't absorbs into skin really well either :( even when 2 hours pass i still have a sticky feeling on my face

#doesn't work

Numbuzin No.5 Vitamin Concentrated Serum 47 ingredients

3.4 /5
from 31 ratings
No Scent (14) Hydrating (12) Absorbs Well (11)
ThomasvV's avatar

Thomas VV

4 months ago
Review

This serum is one of the best all-round anti-oxidant and dark spot serums containing:
- vitamin c
- Glutathion!!
- 5% niacinamide
- Q10
- Alpha Arbutin
(Unfortunately they removed TXA)

Skin type: combi acne prone

This is not just a dark spot serum, its a perfect anti-oxidant serum in the morning. Glutathion is a killer ingredient and the concentration of Vit C is low.

My acne Show more

#great value
#hydrating
#absorbs well
#no scent
Cheeks's avatar

Cheeks

7 months ago
Review

This is an okay serum for brightening. I have dry, eczema and rosacea skin and didn’t have any issues with breakouts or irritation BUT I didn’t see any big improvement either and used for about 3 months. I found that it left a slightly tacky feeling no matter how long I left between steps in my routine. No smells or fragrances so that was also a plus.

#great value
#sticky
#no scent
#doesn't work