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D_COSRX Advanced The Vitamin C 23 Serum
Power-Brightening Pure Vitamin C Serum
COSRX’s Advanced The Vitamin C 23 Serum features a high strength 23% pure vitamin C with Super Vitamin E and Glutathione to target uneven skin tone, early signs of aging, and dullness. Ideal for experienced vitamin C users seeking visible brightening and firmer skin, it absorbs smoothly to leave the complexion more radiant, supple, and revitalized.
Size: 20ml / 0.67fl. oz
$25.00
FAQ
Q. Can I use vitamin C serum every day?
This is a higher concentration of pure vitamin C, so it may come with skin irritation. We recommend you patch test back of the wrist, or on your neck before first use. It can be used every day, however if your skin feels irritated, please apply the product less frequently at first before increasing the frequency. If your skin feels severe irritated, we recommend you use with a moisturizer but if your skin still feels irritated, please apply the product less frequently or stop using it.
Q. What should you not mix with vitamin C?
Mixing with hydroxy acid such as AHA, BHA may cause skin irritation, so we don't recommend using them with vitamin C.
Q. What can vitamin C be mixed with?
Tocotrienol, hyaluronic acid, ceramide, snail, centella
Q. Do you put vitamin C before moisturizer?
Vitamin C is the best to use before skincare. If you use a light water serum-type C serum first and then cover it with a thick cream type, you can absorb more vitamins into your skin.
Q. It has a strange smell. Is this normal?
This serum does not contain fragrances. However, the vitamin C, by nature, has a certain smell that does not affect the potency of the product.
Q. Can I use vitamin C serum every day?
This is a higher concentration of pure vitamin C, so it may come with skin irritation. We recommend you patch test back of the wrist, or on your neck before first use. It can be used every day, however if your skin feels irritated, please apply the product less frequently at first before increasing the frequency. If your skin feels severe irritated, we recommend you use with a moisturizer but if your skin still feels irritated, please apply the product less frequently or stop using it.
Q. What should you not mix with vitamin C?
Mixing with hydroxy acid such as AHA, BHA may cause skin irritation, so we don't recommend using them with vitamin C.
Q. What can vitamin C be mixed with?
Tocotrienol, hyaluronic acid, ceramide, snail, centella
Q. Do you put vitamin C before moisturizer?
Vitamin C is the best to use before skincare. If you use a light water serum-type C serum first and then cover it with a thick cream type, you can absorb more vitamins into your skin.
Q. It has a strange smell. Is this normal?
This serum does not contain fragrances. However, the vitamin C, by nature, has a certain smell that does not affect the potency of the product.
#HIGH-CONCENTRATION #Brightening #PUREVITAMINC
Brighter, Firmer, Clearer in Just 4 Weeks
Based on a 4-week clinical study conducted by Dermacosmetic Skin Science Lab, Korea.
+34.81%
improvement in radiance & brightening
+92.32%
improvement in skin texture
-30.14%
reduction in redness
-17.43%
decrease in pigmentation area
+15.07%
increase in skin elasticity
All clinical studies were conducted by Dermacosmetic Skin Science Laboratory(Korea) from May 3 to June 30, 2025, on 20 adult participants.
WHO IS IT FOR?
Perfect for those already familiar with Vitamin C who want upgrade to a high potency formula for faster and more visible results.
Ideal for dull, tired, or uneven skin, targeting lack of lack of radiance and uneven tone to reveal a brighter, more refined complexion with every use.
Best for those concerned with early signs of aging, including fine lines, loss of elasticity, and rough texture.
Ideal as a targeted solution for dark spots, pigmentation, or stubborn blemish marks that need powerful yet gentle care.
KEY INGREDIENTS
FAQ
What makes COSRX Advanced The Vitamin C 23 Serum different from other Korean Vitamin C serums?
COSRX Advanced The Vitamin C 23 Serum is formulated with a powerful antioxidant network featuring 23% pure Vitamin C, Super Vitamin E (Tocotrienol), and Glutathione. Based on research, this blend helps stabilize inherently unstable pure Vitamin C, allowing it to be delivered gently and effectively to the skin, making it more comfortable to use compared to many traditional Vitamin C serums.
How does the Vitamin C 23 Serum help with dark spots and hyperpigmentation?
COSRX Advanced The Vitamin C 23 Serum combines 23% pure Vitamin C with Super Vitamin E and Glutathione for powerful antioxidant care. This high-strength formula stays fresh, absorbs smoothly, and delivers visible brightening and texture improvement without irritation even for sensitive skin.
Can COSRX Vitamin C 23 Serum refine pores and smooth skin texture?
Yes. Clinical testing showed a 38% reduction in pore volume and over 92% improvement in skin texture after consistent use. This pure Vitamin C 23% serum helps resurface dull areas, reduce the appearance pores, and leave skin smoother and more even-looking.
When can I expect to see visible results from the Vitamin C 23 Serum?
Most users notice improved brightness and smoother texture within two weeks, with visibly clearer, firmer, and more even-toned skin after four weeks of consistent use. Clinical trials confirmed measurable improvements in pigmentation, pore appearance, and elasticity during this period.
Is the COSRX Vitamin C 23 Serum suitable for sensitive or acne-prone skin?
Yes. The formula is non-comedogenic and irritation-tested to ensure it works gently on all skin types. The dual-layer structure combines antioxidant power with soothing hydration from Panthenol and Allantoin, helping repair the skin barrier while minimizing redness or stinging.
How does this serum support anti-aging and skin elasticity?
Vitamin C helps support collagen, while Adenosine boosts this effect for enhanced resilience. Clinical data showed, during this test period, about a 15% improvement in skin elasticity and a reduction in the appearance of wrinkle depth, promoting a smoother, more lifted look with continued use.
How should I store and apply the COSRX Vitamin C 23 Serum for best results?
Keep the serum refrigerated between 3–10°C to maintain freshness. Replace the cap with the provided dropper after opening, shake lightly, and apply a few drops to clean, toned skin. Gently pat until absorbed and follow with moisturizer and SPF during the day.
