Use everyday like a daily vitamin C for your skin
A gentle, water-based vitamin C serum that provides moisture and absorbs quickly without stickiness. Lighter and more refreshing than the Vitamin C 23 Serum, it can be used daily. Regular use will fade blemishes, dark spots, and freckles, while improving overall skin tone.
Size : 20ml / 0.67fl. oz
Recommended for
COSRX The vitamin C 13 serum is ideal for those who want a Vitamin C product for daily use that also cares for hydrating and brightening the complexion.
Target concerns
- Hyperpigmentation
- Anti aging
- Dullness
Texture
Non-sticky, lightweight, watery texture that absorbs well
Color
It has a slight yellowish tint, indicating that it contains pure vitamin C
After cleansing, apply a few drops to the skin during the serum step. Using your fingertips, gently massage the serum into the skin, working from the center of the face outward until fully absorbed.
/KEEP REFRIGERATED (3~10°C)/
*For best results, use immediately after purchase. Once opened, store upright in the refrigerator.
*Cautions*
1. For first use, attach the dropper included in the product package.
2. To preserve the active ingredients, we recommend using within 2 months of opening.
3. Can I use a highly concentrated serum only in the evening? No! This serum can be used both in the morning and evening.
4. If used in the morning, always follow with a sunscreen of SPF 30 or higher.
5. As this product contains a high concentration of Vitamin C, we recommend avoiding use alongside Copper Peptide products, including our Blue Peptide Serum & Cream. For best results, use them at different times of day (morning/evening) to optimize absorption and maximize the benefits of each product.
KEY INGREDIENTS
• 13% Pure Vitamin C :
Improves discoloration and uneven skin tone.
💡Learn More about Vitamin C →
• Tocotrienol(Super Vitamin E) :
Boasts up to 50 times greater anti-oxidizing efficacy than Tocopherol.
• Hyaluronic Acid and Allantoin :
Provides moisture and relieves irritation.
Recommended for
COSRX The vitamin C 13 serum is ideal for those who want a Vitamin C product for daily use that also cares for hydrating and brightening the complexion.
Target concerns
- Hyperpigmentation
- Anti aging
- Dullness
Texture
Non-sticky, lightweight, watery texture that absorbs well
Color
It has a slight yellowish tint, indicating that it contains pure vitamin C
After cleansing, apply a few drops to the skin during the serum step. Using your fingertips, gently massage the serum into the skin, working from the center of the face outward until fully absorbed.
/KEEP REFRIGERATED (3~10°C)/
*For best results, use immediately after purchase. Once opened, store upright in the refrigerator.
*Cautions*
1. For first use, attach the dropper included in the product package.
2. To preserve the active ingredients, we recommend using within 2 months of opening.
3. Can I use a highly concentrated serum only in the evening? No! This serum can be used both in the morning and evening.
4. If used in the morning, always follow with a sunscreen of SPF 30 or higher.
5. As this product contains a high concentration of Vitamin C, we recommend avoiding use alongside Copper Peptide products, including our Blue Peptide Serum & Cream. For best results, use them at different times of day (morning/evening) to optimize absorption and maximize the benefits of each product.
KEY INGREDIENTS
• 13% Pure Vitamin C :
Improves discoloration and uneven skin tone.
💡Learn More about Vitamin C →
• Tocotrienol(Super Vitamin E) :
Boasts up to 50 times greater anti-oxidizing efficacy than Tocopherol.
• Hyaluronic Acid and Allantoin :
Provides moisture and relieves irritation.
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Overall rating: 4.6666665 / 5 from 180 reviews.
The Vitamin C 13 Serum is a water-based formula that provides moisture and absorbs quickly without stickiness. Customers appreciate its ability to brighten dark spots, improve skin tone, and make the skin look fresh and radiant. Opinions vary on its scent and how it feels on the skin.
Review topics: ["improvement","absorbs","results","fit","skin","feels","texture","scent","looks","bottle","ingredients","works","spots","face","formula","difference","complexion","glow","serum","vitamin c","reaction","moisturizer","application","use","makeup","buy","found","sunscreen","brand","tone"].
"I’ve been using this for a few weeks now and I’m honestly so impressed. My skin is pretty sensitive, so I was a bit nervous, but it hasn’t caused any irritation or redness at all. It’s super gentle, sinks in nicely, and has definitely made my skin look brighter and more awake. So glad I added this to my routine!"
"I haven't seen much of a result yet, so I'm going to try the more concentrated formula to see how my skin reacts. For the rest the product is nice to apply."
"I always use vitamin C serum and this one is my favorite."
"the product does exactly what i wanted it to do it makes my skin look smoother and more even while helping it shine."
"This is so soft and even on the skin. Does feel a bit sticky towards the end of application but if you let it dry into the skin that goes away. The scent is different, I won’t lie, but doesn’t linger post application. I have noticed lightening in my melasma since starting CosRx products, but I am using multiple products, so most likely from the combination of all. Great size bottle for the price. It is only 13% pure vitamin C, but it is helping with brightness."
"The smell is a little iffy and I don’t love having to put it in the fridge but it works well!"
"Another COSRX product that I can't live without. It's the only Vit C I use and will continue to purchase. I did try the Vit C 23 but I definitely like how this one works on my aging skin better."
"Very effective and I didn’t have any allergic reaction. Made my acne scars fade"
"I lost count how many bottles I had purchased of this Vitamin C serum. My skin loves it and that is enough for me to come back to it."
"I bought two packs of Vitamin C 13 in January 2026. I emailed to request a refund because the serum has a very strong smell, but I haven't received a response yet."
