# COSRX - The Vitamin C 13 Serum **Brand:** COSRX **Category:** Soins du visage **Code (GTIN/SKU):** 8800311121911 **Canonical URL:** https://openreviews.io/en/reviews/cosrx/cosrx-the-vitamin-c-13-serum-8800311121911 ## Rating: 4.7/5 ★★★★★ — 92 reviews analyzed _Confidence: high_ ## At a glance COSRX - The Vitamin C 13 Serum reviews: 4.7/5 based on 92 analyzed reviews from 2 sites, updated November 2, 2026. Praised: odeur and prix. Criticized: strong Odor and storage Requirements. - Odeur: 16 reviews mention it, mostly positively - Prix: 10 reviews mention it, mostly positively - Sensations / Usage: 6 reviews mention it, mostly positively 92 reviews analyzed: 64 published on OpenReviews and 28 on other sites. Other sites: 1 source, 28 reviews, average rating 4.6/5. How we count reviews: https://openreviews.io/en/methodology ## AI summary This serum is highly appreciated for its ability to brighten and even out dull skin, improving overall appearance and smoothing fine lines. Its lightweight, watery texture sinks in quickly, making it a great addition to skincare routines, particularly for oily or sensitive skin, without causing irritation. However, the serum has a distinct, strong odor that some describe as metallic or reminiscent of coffee, though it usually fades quickly. Users should also note that it requires refrigeration to prevent oxidation and maintain its effectiveness. ## Strengths - Odeur (25%) - Prix (16%) - Sensations / Usage (9%) - Qualité (8%) - Apparence (8%) ## Weaknesses - **Strong Odor** — The product has a prominent, unusual smell during application, though most users find it tolerable as it fades fast. - **Storage Requirements** — This active vitamin C formula must be kept refrigerated to prevent it from oxidizing. ## Frequently asked questions - Does this vitamin C serum have a strong smell? - Is it suitable for sensitive or oily skin types? - Do I need to keep this product in the fridge? - How fast does it show results on dull skin? ## Top reviews ### 5.0/5 · ドゥイ ユリアント · October 12, 2025 Ok ### 4.0/5 · Daniel O · October 9, 2025 Really lovely, good for evening dark spots and creating a glow. You have to keep it in the fridge and it does stink. If your skin can tolerate it, I’d definitely go up to 23%. Best to use at night, as it does react with moisturiser (not in a painful way), meaning you can get orange tide marks. ### 5.0/5 · Richelle Cruz · September 14, 2025 Nice product.. Looks good on face ### 5.0/5 · Riffat · September 13, 2025 The COSRX Pure Vitamin C 23% Serum has quickly become one of my favorite brightening serums. It’s strong enough to make a visible difference in dullness, uneven skin tone, and fine lines, yet the formula feels balanced thanks to the addition of vitamin E and hyaluronic acid.I noticed my skin looking fresher and more radiant within a few weeks, and with consistent use, my complexion feels smoother and more even. The texture is lightweight, absorbs well, and doesn’t leave a heavy or sticky finish.If you’re looking for a powerful yet hydrating Vitamin C serum, this one really delivers. Just remember, like with all skincare, patience and consistency are key to seeing lasting results. ### 5.0/5 · Shamsia · September 6, 2025 I love the this 😍. ### 5.0/5 · Andrea · September 2, 2025 Very good product ### 5.0/5 · May SW · August 31, 2025 This is my 4th bottle and the most gentle vitamin C serum I have ever use. Suitable for sensitive skin. Noticeable effect after using second bottle. ### 4.0/5 · Edna D’Rozario · August 29, 2025 Light weight and absorbs nicely ### 5.0/5 · Lola · August 25, 2025 Lovely product ### 5.0/5 · Hannah Scott · August 24, 2025 really loved this! felt like it really started to help with my hyperpigmentation --- _Source: OpenReviews — https://openreviews.io/en/reviews/cosrx/cosrx-the-vitamin-c-13-serum-8800311121911_