COSRX
COSRX RX Advanced The Vitamin C23 Serum, 20g
COSRX RX Advanced The Vitamin C23 Serum, 20g
@cosme rating: 5.7/7.0
Over 4.55 million bottles sold! C23 Serum has been renewed!
✓ 100% authentic
✓ Ships from Japan in 3-5 days
✓ Duties prepaid for US orders
✓ Tracked delivery via Japan Post
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What it is
Ingredients
Water, ascorbic acid, BG, dimethicone, panthenol, 3-0-ethyl ascorbic acid, squalane, sodium hydroxide, caffeine, sodium hyaluronate, sodium metaphosphate, adenosine, acetyl glucosamine, gardenia fruit extract, allantoin, dextrin, tocotrienol, tocopherol, palm oil, arginine, niacinamide, pentylene glycol, glutathione, sunflower seed oil, methyl trimethicone, safflower oil, camellia seed oil, carrot root extract, licorice root extract, beta-carotene
How to use
After washing your face and toning your skin with lotion, gently press the dropper head, dispense an appropriate amount into your palm, and gently blend into your skin with your fingertips. [Precautions for Use and Storage] Use with caution, paying close attention to any abnormalities on your skin. Do not use on areas with cuts, swelling, eczema, or other abnormalities. Discontinue use if the cosmetics do not suit your skin, i.e., in the following cases. Continuing to use cosmetics may worsen the symptoms, so we recommend consulting a dermatologist. * If you experience any abnormalities such as redness, swelling, itching, irritation, discoloration (white spots, etc.), or darkening during use. If the above abnormalities occur after direct sunlight exposure to the skin where the product was used. Always close the lid tightly after use. Keep out of reach of children. Do not store in extremely hot or cold places or in direct sunlight.
We ship internationally from Japan!
Frequently Asked Questions
Is this authentic?
Yes. Every item is bought from an official seller in Japan, or direct from the brand for pre-orders,
never from resellers or grey market stock. Counterfeits and grey market listings are a real problem in
Asian beauty online, and buying only through official channels is how we rule it out.
What are your shipping rates?
On orders under US$75, shipping is a flat US$20 to the United States and US$10 to all other countries.
Orders of US$75 or more ship free, applied automatically at checkout. Your exact shipping cost is shown before you pay.
How long does delivery take?
These estimates are for International Airmail (Tracked) and include 3 to 5 business days of processing in Japan.
- United States: 12 to 15 business days
- Canada, United Kingdom, France, Germany: 9 to 12 business days
- Australia, New Zealand, Denmark, Finland, India, Indonesia, Italy, Netherlands, Spain, Sweden, Switzerland: 10 to 13 business days
- China, Hong Kong, Malaysia, Singapore, South Korea, Taiwan, Thailand, Vietnam: 8 to 10 business days
- Rest of the world: 11 to 18 business days
Actual delivery can be affected by customs clearance, seasonal congestion, or carrier delays in the destination country, all of which are outside our control.
Do you offer express shipping?
Yes. As of 22 July 2026, we offer International Express Mail through Japan Post. The cost is based on order weight and is calculated automatically at checkout.
Will I pay customs or import fees?
US orders: No. As of July 1, 2026, all US orders ship DDP (duties delivered prepaid), meaning we prepay all import duties on our end. Nothing is due at your door.
Orders outside the US: Possibly. Duties and import taxes are set by your local customs authority and are not collected at checkout, so any charges on delivery are your responsibility.
We're working on rolling out prepaid duties for more countries soon.
The texture is similar to a typical vitamin C serum. It comes in a dropper, making it easy to use, and I mainly use it in the morning. I haven't had any major skin problems, and I think it's helping to stabilize my skin. I'm happy with the feel and results, but I won't be repurchasing it for now, as I want to try out a variety of products.
COSRX Advanced The Vitamin C 23 Serum: ★ This serum contains a highly concentrated amount of pure vitamin C (23%) plus powerful antioxidants to address dark spots and dullness, resulting in brighter, firmer skin! It also contains antioxidants like vitamin E and niacinamide, which supposedly prevent oxidation, a major cause of skin aging. ★ This serum simultaneously moisturizes and treats rough skin, while hyaluronic acid moisturizes, while allantoin and panthenol soothe redness and irritation. It also addresses the dryness and tingling that can be common with vitamin C. The texture is like a light oil, leaving your skin feeling bouncy and smooth upon application. While many vitamin-based products have a strong scent, this one has a pleasant, subtle fragrance. Keep it in the refrigerator.
The texture is similar to a typical vitamin C serum. It comes in a dropper, making it easy to use, and I mainly use it in the morning. I haven't had any major skin problems, and I think it's helping to stabilize my skin. I'm happy with the feel and results, but I won't be repurchasing it for now, as I want to try out a variety of products.
I bought this product because it gave me a perfect compatibility rating on Suzykirei. It's been about three weeks since I started using it (though it may have been compatible with other products), and when I had my skin checked at the cosmetics counter, I noticed a significant improvement, especially in the pores and texture. These two scores are almost perfect. Since I was about to run out of foundation, I had them match my color (a different product), and it brightened my skin by two tones. I haven't noticed any noticeable blemishes disappearing, but it seems to have worked for my skin. I use it after moisturizing my skin with lotion, but I take an appropriate amount and blend it all over my face. It feels sticky and absorbs into my skin, which I think is a sign that it's absorbed. If I don't blend it in enough, it feels like it will mix with the lotion I apply after. It doesn't feel particularly tingly, and I like that it's easily available at drugstores.
COSRX Advanced The Vitamin C 23 Serum: ★ This serum contains a highly concentrated amount of pure vitamin C (23%) plus powerful antioxidants to address dark spots and dullness, resulting in brighter, firmer skin! It also contains antioxidants like vitamin E and niacinamide, which supposedly prevent oxidation, a major cause of skin aging. ★ This serum simultaneously moisturizes and treats rough skin, while hyaluronic acid moisturizes, while allantoin and panthenol soothe redness and irritation. It also addresses the dryness and tingling that can be common with vitamin C. The texture is like a light oil, leaving your skin feeling bouncy and smooth upon application. While many vitamin-based products have a strong scent, this one has a pleasant, subtle fragrance. Keep it in the refrigerator.