Versus

Undefined Beauty R&R Day Serum Versus Numbuzin No.5 Vitamin Concentrated Serum

Serum
Serum
American Brand United States
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 7 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 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

Concerns

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.

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
Skin Conditioning

You might know this ingredient as Ethyl Ascorbic Acid, a more stable version of ascorbic acid.

Like other types of vitamin C, this ingredient has many benefits including reducing wrinkles, skin soothing, dark spot fading, and fighting against free radicals.

3-O-Ethyl Ascorbic Acid interferes with the process of skin darkening, helping to reduce hyperpigmentation. It also encourages the skin to produce more collagen.

Once applied, 3-O-Ethyl Ascorbic Acid is converted to Vitamin C deeper in the skin's layers. This process is slow but makes this ingredient more tolerable for skin.

The optimum pH range for this ingredient is 4 - 5.5

Learn more about 3-O-Ethyl Ascorbic Acid
Antioxidant

Ascorbyl Glucoside is a stable form of Vitamin C. It is created by combining glucose from starch.

When applied to skin, Ascorbyl Glucoside turns into Ascorbic Acid.

Ascorbyl Glucoside is an antioxidant. Antioxidants help fight free-radicals, or molecules that may damage skin cells.

It can help to reduce redness, improve skin texture, reduce the effects of aging, reduce the visibility of dark spots, and brighten skin.

Read more about other types of Vitamin C:

Learn more about Ascorbyl Glucoside
Antioxidant, Bleaching, Skin Conditioning

Alpha-Arbutin is made from hydroquinone and glucose. It may also be derived from the fermentation of soybeans.

This ingredient an antioxidant, meaning it helps protect your skin cells against damage.

Studies show this ingredient helps improve hyperpigmentation and fade discoloration.

Alpha-Arbutin may be used with other ingredients that help with hyperpigmentation. These ingredients include retinol, Vitamin C, niacinamide, and tranexamic acid.

Learn more about Alpha-Arbutin
Smoothing

Niacinamide has emerged as an all-star ingredient due to its many benefits.

It is known to treat acne by reducing inflammation. It also helps fade dark-spots and strengthen the skin by promoting the growth of the ceramide barrier.

Other benefits include smoothing wrinkles and minimizing redness.

The cherry on top? Niacinamide can also help build keratin, a protein that keeps skin firm.

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.

Niacinamide can be mixed with other ingredients to boost benefits. For instance, it has shown to be effective when used with copper, folic acid, and zinc to treat acne.

Learn more about Niacinamide
Humectant, Skin Conditioning, Skin Protecting

Glycerin is already naturally found in your skin. It helps moisturize and protect your skin.

A study from 2016 found glycerin to be more effective as a humectant than AHAs and hyaluronic acid.

As a humectant, it helps the skin stay hydrated by pulling moisture to your skin. The low molecular weight of glycerin allows it to pull moisture into the deeper layers of your skin.

Hydrated skin improves your skin barrier; Your skin barrier helps protect against irritants and bacteria.

Glycerin has also been found to have antimicrobial and antiviral properties. Due to these properties, glycerin is often used in wound and burn treatments.

In cosmetics, glycerin is usually derived from plants such as soybean or palm. However, it can also be sourced from animals, such as tallow or animal fat.

This ingredient is organic, colorless, odorless, and non-toxic.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

Learn more about Glycerin
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 

When to use

15 Routines
80% use in am
20% use in pm
93% use every day
913 Routines
66% use in am
34% use in pm
89% use every day
When to use See routines that use it ->

Reviews

Here's what our community thinks

Undefined Beauty R&R Day Serum 19 ingredients

5.0 /5
from 1 rating
Absorbs Well (1) Great Value (1) Hydrating (1)
xliyahf's avatar

lia

3 months ago
Review

Dropper is hell to screw on but so far I’ve noticed my acne is less inflamed and my skin’s more hydrated & glowy. Good product

#great value
#hydrating
#light
#absorbs well

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