COSRX

COSRX AHA/BHA Refresh Vitamin C Booster Serum

Name: COSRX - AHA/BHA Refresh Vitamin C Booster Serum
Brand: COSRX

Efficacy100/100IrritancyHigh

See all ingredients

Works for

Exfoliation

Glycolic acid, Betaine salicylate + 1 more

Works well

What the product description says

“Serum to gently exfoliate with natural brightening agents like juicy kiwi and dragon fruit extract.”

Source: Cosrx

This product can help exfoliate the skin. In other words, it helps break down the bonds between dead cells on the surface of the skin and speed up the skin turnover. Skin often appears softer and brighter after exfoliation, but overdoing it can result in disrupted skin barrier. The following ingredient is doing the exfoliating job in this product: betaine salicylate, glycolic acid.

Glycolic acidKey activeEffect: HighAn alpha-hydroxy acid (AHA) that helps to remove the dead skin cells on the surface of the skin reveling a more even, smoother complexation. It is also able to stimulate collagen production with long-term use. Could help to reduce pore congestion. It can be irritating to the skin. Apply sunscreen daily if using products with glycolic acid~1.4–2.2%

Betaine salicylateKey activeEffect: HighExfoliating acid, a "relative" of salicylic acid~0.1–0.5%

AllantoinEffect: Low, below effective doseHelps calm down inflammation in skin and can help reduce itching. Helps to repair the skin barrier and keep skin hydrated~0.4–0.9%

Moisturizing

Niacinamide, Panthenol + 6 more

Works well

What the product description says

“Hydrating and soft serum insta...”

Source: Cosrx

This product contains good ingredients to attract water to the upper layer of the skin. These ingredients are called "humectants": betaine, glycerin.

When humectants are on the surface of the skin, they “pull in” the moisture from the outside environment, or from within deeper layers of the skin. If the air is dry, humectants can speed up the moisture loss from the skin. This is why it is a good idea to use another product on top of this one to help "seal in" the moisture (look for ingredients like dimethicone, squalane, oils and butters).

The following ingredients in this product are especially good for supporting the skin barrier and helping with the hydration level: niacinamide, panthenol

NiacinamideHeroEffect: HighIs proven to be effective in reducing blemishes, evening out skin tone and helping to improve lines and wrinkles. It helps the skin to repair sun damage, calm down inflammation and keep maintain good levels of moisture. The concentration of about 2% is effective for supporting the skin barrier and evening out the skin tone. Concentration of 4-6% is better for helping with acne and balancing the sebum production~2.7–4%

PanthenolHero· HumectantEffect: HighHelps attract water to the upper layer of the skin and can help improve skin barrier function~0.55–1.3%

BetaineKey active· HumectantEffect: HighHelps attract water to the upper layer of the skin and improves the product texture~1.2–1.8%

GlycerinKey active· HumectantEffect: HighOne of the best moisturizing ingredients. Naturally present in skin. It attracts water to the upper layer of the skin working as a humectant~0.45–1.05%

Sodium hyaluronateKey active· HumectantEffect: HighOne of the best moisturizing ingredients. Attracts water into the upper layer of the skin~0.2–0.75%

AdenosineKey activeEffect: MediumMight help improve cell turnover and reduce inflammation in skin. One study shows that the ingredients might be able to help reduce dynamic wrinkles (for example, in the corners of the eyes or on the forehead)~0.2–0.75%

Butylene glycol· HumectantEffect: LowUsed to create a nice product texture and help delivery of other ingredients. Might be somewhat helpful in attracting water to the upper layer of the skin~3.3–4.9%

AllantoinUnder-dosedHelps calm down inflammation in skin and can help reduce itching. Helps to repair the skin barrier and keep skin hydrated~0.4–0.9%

Evens skin tone

Niacinamide, Glycolic acid + 2 more

Works well

What the product description says

“Daily peeling serum extracted from juicy Kiwi and Dragon Fruit Skin to care for dead skin cells and enhance the overall skin tone.”

Source: Cosrx

This product can help reduce hypepigmentation and even out the skin tone because it contains the following effective ingredients: alpha-arbutin, betaine salicylate, glycolic acid, niacinamide

Keep in mind that you would need to apply any topical skincare targetted at hypigmentation consistently for a couple of months to get a result. No topical skincare product can help get rid of hyperpigmentation (including post-acne marks and age spots) instantly.

NiacinamideKey activeEffect: HighIs proven to be effective in reducing blemishes, evening out skin tone and helping to improve lines and wrinkles. It helps the skin to repair sun damage, calm down inflammation and keep maintain good levels of moisture. The concentration of about 2% is effective for supporting the skin barrier and evening out the skin tone. Concentration of 4-6% is better for helping with acne and balancing the sebum production~2.7–4%

Alpha-arbutinKey activeEffect: HighMight help reduce hyperpigmentation when used regularly over a long period of time. Is more effective than beta-arbutin~0.1–0.45%

Ascorbyl glucosideUnder-dosedA vitamin C derivative that is more stable but less potent than pure form of vitamin C. Has a potential to boost collagen production, nutralise free radicals and reduce hyperpigmentation, but the required concentration is likely to be much higher than for the pure form of vitamin C, limiting the ingredient's effectiveness in products~0.15–0.6%

Anti-aging

Side benefit the brand mentions · Niacinamide, Glycolic acid + 2 more

Works well

What the product description says

“Infused with naturally-derived exfoliators and 57% Golden-Rx Complex, this lightweight and dermatologically tested serum diminishes the appearance of fine lines and brightens the complexion.”

Source: Soko Glam

This product can help reduce and prevent fine lines and wrinkles, improve skin elasticity and firmness because it contains adenosine, glycolic acid, niacinamide.

Keep in mind that it typically takes at least 6 weeks to notice any results because the changes that are needed to improve fine lines and elasticity happen in the deeper layers of the skin. No topical anti-aging product can “erase” wrinkles or fully reverse signs of aging.

AdenosineKey activeEffect: HighMight help improve cell turnover and reduce inflammation in skin. One study shows that the ingredients might be able to help reduce dynamic wrinkles (for example, in the corners of the eyes or on the forehead)~0.2–0.75%

Anti-blemish

Side benefit · Niacinamide, Glycolic acid + 2 more

Works well

This product can help reduce breakouts and clogged pores because it contains the following ingredient: niacinamide. This ingredient is used for treating acne and can have a noticeable effect.

In addition, this product contains betaine salicylate. It can help in reducing blemishes, even though it is less effective.

The following ingredient (ingredients) in this product might be helpful, but there is no evidence to confirm that it actually works: glycolic acid

Glycolic acidKey activeEffect: MediumAn alpha-hydroxy acid (AHA) that helps to remove the dead skin cells on the surface of the skin reveling a more even, smoother complexation. It is also able to stimulate collagen production with long-term use. Could help to reduce pore congestion. It can be irritating to the skin. Apply sunscreen daily if using products with glycolic acid~1.4–2.2%

Betaine salicylateKey activeEffect: HighExfoliating acid, a "relative" of salicylic acid~0.1–0.5%

AllantoinEffect: Low, below effective doseHelps calm down inflammation in skin and can help reduce itching. Helps to repair the skin barrier and keep skin hydrated~0.4–0.9%

Can it cause trouble?

Irritancy

3 strong irritants: Citrus aurantium bergamia fruit oil, Menthyl lactate + 1 more — patch-test recommended

High risk

We flagged 11 ingredients with irritancy potential. Severity depends on your sensitivity threshold; the table lists the worst offenders first.

IngredientFunctionIrritationEst. amount

Actinidia chinensis fruit extractA plant extract that might have some anti-oxidant properties, but evidence of effectiveness in skin is lackingHigh~23–34%est.

Glycolic acidAn alpha-hydroxy acid (AHA) that helps to remove the dead skin cells on the surface of the skin reveling a more even, smoother complexation. It is also able to stimulate collagen production with long-term use. Could help to reduce pore congestion. It can be irritating to the skin. Apply sunscreen daily if using products with glycolic acidHigh~1.4–2.2%est.

Citrus aurantium bergamia fruit oilA plant oil with a high content of volatile compounds that can irritate the skin and lead to allergic reactions. Can lead to photosensitivityHigh~0.1–0.45%est.

Menthyl lactateUsed as a fragrance. Can be irritatingHigh~0.1–0.4%est.

Mentha haplocalix extract—High~0.1–0.35%est.

Hippophae rhamnoides waterA plant-infused water. The concentration of compounds with potential skin benefits is unlikely to be effectiveMedium~4.4–6.7%est.

1,2-hexanediolA preservativeMedium~0.55–1.25%est.

Polyglyceryl-10 laurateHelps water and oil mix togetherMedium~0.35–0.8%est.

Ascorbyl glucosideA vitamin C derivative that is more stable but less potent than pure form of vitamin C. Has a potential to boost collagen production, nutralise free radicals and reduce hyperpigmentation, but the required concentration is likely to be much higher than for the pure form of vitamin C, limiting the ingredient's effectiveness in productsMedium~0.15–0.6%est.

Betaine salicylateExfoliating acid, a "relative" of salicylic acidMedium~0.1–0.5%est.

Alpha-arbutinMight help reduce hyperpigmentation when used regularly over a long period of time. Is more effective than beta-arbutinMedium~0.1–0.45%est.

Comedogenic

Clean of flagged comedogenic ingredients

None flagged

Alternatives

Cheaper, or higher on efficacy

numbuzin No.5 Vitamin Concentrated Serum (Non-TXA Version) 30ml

Cheaper88% match

$15.41

Dr. Althea Vitamin C Boosting Serum 30ml

Cheaper86% match

$17.50

View all alternatives

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Ingredients

Filter by role to see what each ingredient is doing.

Actinidia chinensis fruit extract~23–34%

Irritant · high

Irritation risk: High

Works for

Anti-oxidation

A plant extract that might have some anti-oxidant properties, but evidence of effectiveness in skin is lacking

More about Actinidia chinensis fruit extract

Hylocereus undatus fruit extract~5.1–7.6%

Formula

Irritation risk: Low

More about Hylocereus undatus fruit extract

Hippophae rhamnoides water~4.4–6.7%

Irritant · medium

Irritation risk: Medium

A plant-infused water. The concentration of compounds with potential skin benefits is unlikely to be effective

More about Hippophae rhamnoides water

Butylene glycol~3.3–4.9%

Formula

Irritation risk: Low

Works for

Moisturizing

Used to create a nice product texture and help delivery of other ingredients. Might be somewhat helpful in attracting water to the upper layer of the skin

More about Butylene glycol

Niacinamide~2.7–4%

Hero · Moisturizing, Anti-blemish

Irritation risk: Low

Works for

Anti-agingAnti-blemishEvens skin toneMoisturizingReduces irritationAnti-inflammatoryAntibacterialReduces redness

Is proven to be effective in reducing blemishes, evening out skin tone and helping to improve lines and wrinkles. It helps the skin to repair sun damage, calm down inflammation and keep maintain good levels of moisture. The concentration of about 2% is effective for supporting the skin barrier and evening out the skin tone. Concentration of 4-6% is better for helping with acne and balancing the sebum production

More about Niacinamide

1,2-hexanediol~0.55–1.25%

Irritant · medium

Irritation risk: Medium

A preservative

More about 1,2-hexanediol

Glycolic acid~1.4–2.2%

Key activeIrritant · high

Irritation risk: High

Works for

Anti-agingEvens skin toneExfoliationAnti-blemish

An alpha-hydroxy acid (AHA) that helps to remove the dead skin cells on the surface of the skin reveling a more even, smoother complexation. It is also able to stimulate collagen production with long-term use. Could help to reduce pore congestion. It can be irritating to the skin. Apply sunscreen daily if using products with glycolic acid

More about Glycolic acid

Betaine~1.2–1.8%

Key active

Irritation risk: Low

Works for

Moisturizing

Helps attract water to the upper layer of the skin and improves the product texture

More about Betaine

Sodium hydroxide~1.1–1.6%

Formula

Irritation risk: Low

Used to adjust the product's pH

More about Sodium hydroxide

Water~0.9–1.35%

Formula

Irritation risk: Low

Plain old water

More about Water

Panthenol~0.55–1.3%

Hero · Moisturizing

Irritation risk: Low

Works for

MoisturizingReduces rednessReduces irritation

Helps attract water to the upper layer of the skin and can help improve skin barrier function

More about Panthenol

Allantoin~0.4–0.9%

Under-dosed

Irritation risk: Low

Works for

Anti-inflammatoryMoisturizingReduces irritationReduces rednessAnti-blemishExfoliation

Helps calm down inflammation in skin and can help reduce itching. Helps to repair the skin barrier and keep skin hydrated

More about Allantoin

Hydroxyethylcellulose~0.5–1.15%

Formula

Irritation risk: Low

Used to thicken product formulations and create gel-like textures

More about Hydroxyethylcellulose

Glycerin~0.45–1.05%

Key active

Irritation risk: Low

Works for

Moisturizing

One of the best moisturizing ingredients. Naturally present in skin. It attracts water to the upper layer of the skin working as a humectant

More about Glycerin

Polyglyceryl-10 myristate~0.4–0.9%

Formula

Irritation risk: Low

More about Polyglyceryl-10 myristate

Polyglyceryl-10 laurate~0.35–0.8%

Irritant · medium

Irritation risk: Medium

Works for

Cleansing

Helps water and oil mix together

More about Polyglyceryl-10 laurate

Sodium hyaluronate~0.2–0.75%

Key active

Irritation risk: Low

Works for

Moisturizing

One of the best moisturizing ingredients. Attracts water into the upper layer of the skin

More about Sodium hyaluronate

Adenosine~0.2–0.75%

Key active

Irritation risk: Low

Works for

Anti-agingMoisturizingAnti-oxidation

Might help improve cell turnover and reduce inflammation in skin. One study shows that the ingredients might be able to help reduce dynamic wrinkles (for example, in the corners of the eyes or on the forehead)

More about Adenosine

Ascorbyl glucoside~0.15–0.6%

Under-dosedIrritant · medium

Irritation risk: Medium

Works for

Anti-agingAnti-oxidationEvens skin tone

A vitamin C derivative that is more stable but less potent than pure form of vitamin C. Has a potential to boost collagen production, nutralise free radicals and reduce hyperpigmentation, but the required concentration is likely to be much higher than for the pure form of vitamin C, limiting the ingredient's effectiveness in products

More about Ascorbyl glucoside

Citrus aurantium bergamia fruit oil~0.1–0.45%

Irritant · high

Irritation risk: High

A plant oil with a high content of volatile compounds that can irritate the skin and lead to allergic reactions. Can lead to photosensitivity

More about Citrus aurantium bergamia fruit oil

Betaine salicylate~0.1–0.5%

Key activeIrritant · medium

Irritation risk: Medium

Works for

Anti-blemishExfoliation

Exfoliating acid, a "relative" of salicylic acid

More about Betaine salicylate

Alpha-arbutin~0.1–0.45%

Key activeIrritant · medium

Irritation risk: Medium

Works for

Evens skin tone

Might help reduce hyperpigmentation when used regularly over a long period of time. Is more effective than beta-arbutin

More about Alpha-arbutin

Menthyl lactate~0.1–0.4%

Irritant · high

Irritation risk: High

Used as a fragrance. Can be irritating

More about Menthyl lactate

Mentha haplocalix extract~0.1–0.35%

Irritant · high

Irritation risk: High

More about Mentha haplocalix extract

Ingredient list view

Actinidia chinensis fruit extract, Hylocereus undatus fruit extract, Hippophae rhamnoides water, Butylene glycol, Niacinamide, 1,2-hexanediol, Glycolic acid, Betaine, Sodium hydroxide, Water, Panthenol, Allantoin, Hydroxyethylcellulose, Glycerin, Polyglyceryl-10 myristate, Polyglyceryl-10 laurate, Sodium hyaluronate, Adenosine, Ascorbyl glucoside, Citrus aurantium bergamia fruit oil, Betaine salicylate, Alpha-arbutin, Menthyl lactate, Mentha haplocalix extract

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Worth comparing, line by line.

Match % combines shared ingredients, the first five ingredients, shared actives and hero ingredients, irritancy (lower counts in the alternative's favour), texture and body area. Only products in the same routine step are compared.

Side-by-side comparison of this product against its closest alternatives
	COSRXAHA/BHA Refresh Vitamin C Booster SerumYOUR PRODUCT	numbuzinNo.5 Vitamin Concentrated Serum (Non-TXA Version) 30ml	Dr. AltheaVitamin C Boosting Serum 30ml	JUMISOAll Day Vitamin VC-IP 1.0 Firming Serum
Match	—	88%	86%	85%
Price	$30.69	$15.41−$15.28	$17.50−$13.19	$13.71−$16.98
Shared key ingredients	—	6 of 11	7 of 11	7 of 11
Key difference	—	Ceramide Np	3-O-Ethyl Ascorbic Acid	Ascorbyl Tetraisopalmitate
Irritancy	High	Medium	Medium	Low
Drying alcohol	—	—	—	—
	View product	Shop	Shop	Shop

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Product summary

"COSRX - AHA/BHA Refresh Vitamin C Booster Serum" is effective for: Moisturizing, Exfoliation, Anti-blemish, Evens skin tone and Anti-aging

Ingredient callouts

A good concentration of Niacinamide (2.70% - 4.00%). Niacinamide is a well-studied multi-tasking active. It is stable, and can work well in almost any hydrating formulation. There is solid evidence that Niacinamide can help support skin barrier, regulate oil production and reduce acne and clogged pores. It also helps to fight photodamage and improve the skin tone, reducing pigmentation marks.
This product contains acids (glycolic acid 1.40% - 2.20%). Their concentration is low, and they will not have a strong exfoliating effect. Instead, they work to support the skin natural acid mantle and to attract water (as humectants).
Adenosine 0.20% - 0.75%. It is a chemical present inside our skin cells. A clinical trial confirmed that topical application of Adenosine in a low concentration can reduce dynamic wrinkles (these are the wrinkles that appear with age in a places where our mimic is the most active, for example, in the corners of the eyes or on the forehead).
Panthenol (pro-vitamin B5) at about 0.55% - 1.35% concentration. In this concentration, Panthenol works effectively to improve the skin barrier and reduce inflammation.
Humectants (sodium hyaluronate 0.30% - 0.75%, panthenol 0.55% - 1.35%, glycerin 0.45% - 1.00% and betaine 1.20% - 1.80%). These ingredients help attract water to the upper layer of the skin and improve the skin hydration.