COSRX AHA/BHA Refresh Vitamin C Booster Serum Review

COSRX AHA/BHA Refresh Vitamin C Booster Serum
3.6
/ 10
Moisturizing
7.2 Humectancy icon Humectancy
0.0 Occlusivity icon Occlusivity
3.4Anti-wrinkle icon/ 10
Anti-wrinkle
Rich
in Antioxidants
Review

Does COSRX AHA/BHA Refresh Vitamin C Booster Serum Work?

 
According to CreamScan AI's analysis of the ingredient list, here’s what COSRX AHA/BHA Refresh Vitamin C Booster Serum has to offer:
 
  • Light moisturizing. It has a moisturizing rating of 3.6 out of 10.
  • Modest anti-wrinkle efficacy: COSRX AHA/BHA Refresh Vitamin C Booster Serum has an anti-wrinkle rating of 3.4 out of 10 so you may expect some, although limited, effect on wrinkles.
  • Antioxidant protection.

Key Benefits of COSRX AHA/BHA Refresh Vitamin C Booster Serum

 
These are the key benefits you can expect from using COSRX AHA/BHA Refresh Vitamin C Booster Serum:
 

Lightweight Purely Humectant Moisturizer Well-Suited for Oily Skin

According to CreamScan analysis, COSRX AHA/BHA Refresh Vitamin C Booster Serum is lightly moisturizing, with a moisturizing rating of 3.6 out of 10.

Is it more humectant or occlusive? Purely humectant. It has zero occlusivity (we didn't find any occlusive ingredients on the ingredient list) and a high humectancy of 7.2 out of 10, primarily due to the high content of Butylene Glycol (est. ≈3.0%) and Niacinamide (est. ≈2.0%).

This humectant-rich product, when used alone as a moisturizer, is well-suited for oily skin, providing moderate hydration in a lightweight, fast-absorbing formula without any occlusive ingredients.

Tip: Certain studies suggest that humectants alone may not effectively moisturize the skin. If you use this product as your only moisturizer, we recommend following it with one that contains at least some occlusive ingredients.

A Humectant Enhancement for Any Skincare Routine

But it’s not limited to oily skin - such a humectant enhancement will also positively contribute to the moisturizing efficacy of any skincare routine when used as a step before applying the main moisturizer. This type of formulation is typically used in serums, where a light, fast-absorbing texture is key.

Please refer to the Ratings section below for details of the moisturizing rating calculation.

Modest Anti-Wrinkle Efficacy

According to CreamScan analysis, COSRX AHA/BHA Refresh Vitamin C Booster Serum has a modest level of anti-wrinkle efficacy, rated 3.4 out of 10.

It contains 2 active ingredients with proven anti-wrinkle efficacy:

  • Niacinamide (est. ≈2.0%),
     one of the most effective and well-researched anti-wrinkle ingredients. A clinical study involving 30 participants (Kawada et al.) confirmed that a cream with 4% niacinamide reduced the average depth of wrinkles around the eyes by 9% after 8 weeks of use, compared to a vehicle (the same formulation without niacinamide).
  • Glycolic Acid (est. ≈1.3%),
     a highly effective ingredient in peelings but with moderate anti-wrinkle efficacy in leave-on skincare products, as supported by a single clinical study. This study, involving 72 participants (Thibault et al.), demonstrated that a lotion with 5% GA reduced the fine wrinkling score by 6% after 34 days of use, compared to a vehicle (the same formulation without GA).
Among others, COSRX AHA/BHA Refresh Vitamin C Booster Serum also contains contains Adenosine and Ascorbyl Glucoside, two ingredients often marketed as effective in reducing wrinkles. However, the studies supporting the anti-wrinkle claims of these ingredients provide insufficient evidence of efficacy according to CreamScan Research Evaluation Standards. Therefore, these ingredients do not contribute to the anti-wrinkle rating.
 
Moisturizers, when used regularly, are proven to prevent wrinkle formation and even reduce existing wrinkles. Therefore, this product, like any other moisturizer, can deliver some anti-wrinkle effects through its moisturizing action.
 

Please refer to the Ratings section below for details of the anti-wrinkle rating calculation.

Rich in Skin-Protecting Antioxidants

We estimate that COSRX AHA/BHA Refresh Vitamin C Booster Serum is rich (> 3%) in antioxidants, specifically Actinidia Chinensis (Kiwi) Fruit Extract (est. ≈75.0%) and Niacinamide (est. ≈2.0%).

A key benefit of antioxidants is their ability to reduce oxidative stress caused by free radicals and therefore prevent accelerated skin aging. Studies also show that antioxidants can protect against environmental damage such as UV radiation and pollution, and help reduce inflammation and skin redness.

Please note that this is not a complete list of benefits. We are in the process of enhancing our AI model to incorporate anti-pigmentation, exfoliation and anti-acne ratings.

Things to Be Aware Of: COSRX AHA/BHA Refresh Vitamin C Booster Serum

 
CreamScan AI identified a few things to consider before adding COSRX AHA/BHA Refresh Vitamin C Booster Serum to your skincare routine:
 

If It’s Your Only Moisturizer, It Needs to Be Paired with Some Occlusives

While humectants are highly effective at attracting water to the skin, studies (J. N. Kraft, C. W. Lynde) suggest they may not be efficient when used alone.

One major drawback of purely humectant moisturization is that the water attracted by humectants to the upper layers of the skin can evaporate completely into the environment through transepidermal water loss (TEWL). Adding occlusive ingredients helps seal this moisture into the skin and prevent further water loss.

If you’re using COSRX AHA/BHA Refresh Vitamin C Booster Serum as your only moisturizer, consider pairing it with one that contains at least some occlusive ingredients, such as oils, butters, or silicones. These work alongside humectants to create a protective barrier, locking in hydration and ensuring longer-lasting moisturization. The amount of occlusive needed depends on your skin type - the drier the skin, the more occlusives it requires.

If this product is used not as a standalone moisturizer but as part of your skincare routine, such as a toner or serum, it should be applied before your main moisturizer (unless it's a sunscreen), which will provide the necessary occlusivity on top of it.

Pros & Cons of COSRX AHA/BHA Refresh Vitamin C Booster Serum

 
Here’s an overview of the pros and cons of COSRX AHA/BHA Refresh Vitamin C Booster Serum to help you decide if it’s the right choice for your skincare routine:
 

Pros:

  • Humectant moisturizing well-suited for oily skin
  • Lightweight texture
  • A humectant moisturizing enhancement for any skincare routine
  • Offers modest anti-wrinkle efficacy
  • Rich in antioxidants that combat oxidative stress associated with accelerated skin aging and defend against environmental damage such as UV radiation and pollution

Cons: 

  • Needs occlusives to seal in humectants if used as a standalone moisturizer

Ingredients

Est. % Ingredient Origin Functions
75
6
4
3
2
1.5
1.3
1
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Est. %
Actinidia Chinensis (Kiwi) Fruit Extract
Function:
Origin:
Hylocereus Undatus Fruit Extract
Function:
Origin:
Hippophae Rhamnoides Water
Function:
Origin:
Butylene Glycol
Function:
Origin:
Niacinamide
Function:
Origin:
1,2-Hexanediol
Function:
Origin:
Glycolic Acid
Function:
Origin:
Betaine
Function:
Origin:
Sodium Hydroxide
Function:
Origin:
Water
Function:
Origin:
Panthenol
Function:
Origin:
Allantoin
Function:
Origin:
Hydroxyethylcellulose
Function:
Origin:
Glycerin
Function:
Origin:
Polyglyceryl-10 Myristate
Function:
Origin:
Polyglyceryl-10 Laurate
Function:
Origin:
Sodium Hyaluronate
Function:
Origin:
Adenosine
Function:
Origin:
Ascorbyl Glucoside
Function:
Origin:
Citrus Aurantium Bergamia (Bergamot) Fruit Oil
Function:
Origin:
Betaine Salicylate
Function:
Origin:
Alpha-Arbutin
Function:
Origin:
Menthyl Lactate
Function:
Origin:
Mentha Haplocalix Extract
Function:
Origin:

Ratings

All humectants
7.2
3
2
1
0.3
0.3
0.3
0.3
Benchmark
10
All occlusives
0.0
None
Benchmark
20
Moisturizing rating
3.6
Ingredient Est. % Benchmark Raiting
Humectancy All humectants 7.2 10
7.2
3
2
1
0.3
0.3
0.3
0.3
Occlusivity All occlusives 0.0 20
0.0
None
Moisturizing rating
3.6
Ingredient Est. % Benchmark Humectancy
3
2
1
0.3
0.3
0.3
0.3
All humectants 7.2 10
7.2
All humectants
7.2
3
2
1
0.3
0.3
0.3
0.3
Benchmark
10
Ingredient Est. % Benchmark Occlusivity
None
All occlusives 0.0 20
0.0
All occlusives
0.0
None
Benchmark
20
Ingredient
Ingredient anti-wrinkle power
when present at, %
in this formula est. %
Rating
6 /10 4 2 3
1.5 /10 5 1.3 0.4
n/a
- 0.3 -
n/a
- 0.3 -
Total
3.4
Niacinamide
3
Ingredient anti-wrinkle power
6 /10
when present at, %
4
in this formula, est. %
2
Glycolic Acid
0.4
Ingredient anti-wrinkle power
1.5 /10
when present at, %
5
in this formula, est. %
1.3
Adenosine
-
Ingredient anti-wrinkle power
n/a
when present at, %
-
in this formula, est. %
0.3
Ascorbyl Glucoside
-
Ingredient anti-wrinkle power
n/a
when present at, %
-
in this formula, est. %
0.3
Anti-wrinkle rating
3.4
Ingredient Est. % Benchmark
Rich in Antioxidants
75
2
0.3
0.3
0.3
All antioxidants 77.9 3 Rich in antioxidants
All antioxidants
77.9
Actinidia Chinensis (Kiwi) Fruit Extract
75
Niacinamide
2
Sodium Hyaluronate
0.3
Ascorbyl Glucoside
0.3
Alpha-Arbutin
0.3
Benchmark
3
Ingredient Est. % Benchmark
Rich in Soothing
2
0.3
0.3
All soothing 2.6 5 No
All soothing
2.6
2
0.3
0.3
Benchmark
5

Ingredients explained

Actinidia Chinensis (Kiwi) Fruit Extract
Est. %75
Function
Origin
Actinidia Chinensis (Kiwi) Fruit ExtractDerived from the golden kiwi fruit, this extract is rich in humectant polysaccharides and antioxidant organic acids, as well as phenolic compounds.
Hylocereus Undatus Fruit Extract
Est. %6
Function
Origin
Hylocereus Undatus Fruit Extract
Hippophae Rhamnoides Water
Est. %4
Function
Origin
Hippophae Rhamnoides Water
Butylene Glycol
Est. %3
Function
Origin
Butylene Glycol

A clear, colorless liquid humectant that draws moisture to the skin. The humectancy of butylene glycol, owed to its two hydroxyl groups, is quite considerable, although not as powerful as glycerin, which contains three hydroxyl groups.

Niacinamide
Est. %2
Function
Origin
Niacinamide

Also known as vitamin B3, this ingredient is a true superstar with confirmed moisturizing, anti-acne, hyperpigmentation, and antioxidant benefits. Two studies confirm its significant anti-wrinkle efficacy.

1,2-Hexanediol
Est. %1.5
Function
Origin
1,2-HexanediolA multi-functional formula helper. It is a well-studied preservtive against bacteria and can help pigments and fragrances disperse evenly in a formula.
Glycolic Acid
Est. %1.3
Function
Origin
Glycolic Acid

The second most used AHA (after lactic acid) known for its potent exfoliating and smoothing effects. It increases skin cell turnover, which is beneficial for treating acne. When used in peels, glycolic acid has confirmed anti-wrinkle efficacy, though it is less effective in leave-on products like creams and serums.

Betaine
Est. %1
Function
Origin
BetaineAn ingredient derived from the sucrose in sugar beets. It has a negative chemical charge and a positive chemical charge on the same molecule. This allows betaine to be hygroscopic or humectant and thus provide moisturization by drawing water to the skin.
Sodium Hydroxide
Est. %0.3
Function
Origin
Sodium Hydroxide

An ingredient that is able to bring the pH of a product up, thereby making it less harsh on the skin.

Water
Est. %0.3
Function
Origin
WaterThe most used ingredient in skincare. Its concentration defines the product texture: rich creams may have about 50% of water while a light jelly about 90%. Water doesn’t moisturize the skin by itself and is used in skincare as a solvent for other ingredients.
Panthenol
Est. %0.3
Function
Origin
PanthenolA popular soothing and moisturizing derivative of vitamin B5. Panthenol is particularly beneficial for dry, flaking, burned, or damaged skin. It is used to alleviate the symptoms of a rash, dermatitis, eczema, chapped lips, and sunburn.
Allantoin
Est. %0.3
Function
Origin
AllantoinA fluffy, white powder that acts as a humectant due to its water-loving chemistry and as an exfoliant that helps to remove dead skin cells. It has also been shown to be very soothing to irritated and inflamed skin.
Hydroxyethylcellulose
Est. %0.3
Function
Origin
HydroxyethylcelluloseA naturally-derived thickener that can form clear gel textures without the slimy feeling, unlike some other natural gel-formers.
Glycerin
Est. %0.3
Function
Origin
Glycerin

The most popular moisturizing ingredient in the world. It is a powerful humectant – cheap yet very effective.

Polyglyceryl-10 Myristate
Est. %0.3
Function
Origin
Polyglyceryl-10 MyristateA solubilizer that can help incorporate small amounts of oil to an otherwise watery product while providing lightweight skin feel.
Polyglyceryl-10 Laurate
Est. %0.3
Function
Origin
Polyglyceryl-10 LaurateA vegetable glycerin or synthetically produced emulsifier and gentle cleansing agent. It won't leave skin feeling tight or dry when used to cleanse.
Sodium Hyaluronate
Est. %0.3
Function
Origin
Sodium Hyaluronate

A sodium salt of famous hyaluronic acid. A potent humectant that hydrates the skin, supports collagen function, and fills out small wrinkles. Sodium hyaluronate also offers soothing and antioxidant properties.

Adenosine
Est. %0.3
Function
Origin
Adenosine

A key molecule responsible for energy transportation, signaling, and enzyme activity. Adenosine is a popular anti-wrinkle ingredient, however, the key study about its anti-wrinkle efficacy (1) does not meet CreamScan Research Evaluation Standards as it is not double-blind.

Ascorbyl Glucoside
Est. %0.3
Function
Origin
Ascorbyl GlucosideA derivative of vitamin C. It is more stable and less irritating than ascorbic acid. There are unfortunately no clinical studies on ascorbyl glucoside’s anti-pigment or anti-acne efficacy alone.
Citrus Aurantium Bergamia (Bergamot) Fruit Oil
Est. %0.3
Function
Origin
Citrus Aurantium Bergamia (Bergamot) Fruit Oil

An essential oil expressed from the peels of the bergamot orange. The scent of bergamot oil is woodier than those of other citrus essential oils. This essential oil is still not recommended if you are sensitive to citrus fruits.

Betaine Salicylate
Est. %0.3
Function
Origin
Betaine Salicylate
Alpha-Arbutin
Est. %0.3
Function
Origin
Alpha-Arbutin
Menthyl Lactate
Est. %0.3
Function
Origin
Menthyl LactateA derivative of menthol that has the same fresh, cooling effect on the skin, but that is less sensitizing and doesn’t have the strong mint scent of menthol.
Mentha Haplocalix Extract
Est. %0.3
Function
Origin
Mentha Haplocalix Extract