COSRX Advanced Vitamin C 23 Serum 20ml, 2-Pack

Features

COSRX Advanced The Vitamin C 23 Serum is a high-potency formula designed to provide intensive care for skin tone, radiance, and texture. This serum features a dual-layered, stabilized design that maximizes the efficacy of 23% pure Vitamin C while minimizing skin irritation. It is formulated to provide antioxidant, brightening, and anti-aging benefits, helping to improve the appearance of dullness, blemishes, and loss of elasticity.

The product is housed in specially engineered packaging designed to maintain the stability of the high-content formula by blocking light, heat, and oxygen, and managing internal gas pressure. COSRX has developed this serum to be suitable for sensitive and acne-prone skin, having successfully completed relevant dermatological tests.

Benefits

This serum offers comprehensive skin improvement, targeting blemishes, uneven tone, and early signs of aging. It works to brighten the complexion, improve skin texture, and provide firming care. The formula is designed to be gentle yet effective, ensuring that users can incorporate a high-concentration Vitamin C treatment into their routine with comfort.

Main Ingredients and their effects

Ascorbic Acid (23%): Pure Vitamin C that provides powerful antioxidant, brightening, and anti-aging effects by neutralizing free radicals and improving uneven skin tone.

Super Vitamin E (Tocotrienol) & Tocopherol: These ingredients work in synergy with Vitamin C to enhance antioxidant protection and support overall skin health.

Adenosine: Included to provide targeted anti-aging care and improve skin elasticity.

Niacinamide: Works to boost the brightening effects of the serum, helping to refine skin tone.

Panthenol, Hyaluronic Acid, & Allantoin: A moisturizing and soothing blend that ensures the high-concentration formula remains gentle and hydrating on the skin.

Clinical test results

Clinical trials conducted on 20 adult men and women (May 3, 2025 – June 30, 2025) demonstrated significant improvements: skin blemish traces improved by 8.87%, skin clarity by 15.06%, deep melanin by 14.15%, skin radiance by 34.81%, skin texture by 92.32%, and surface elasticity by 15.07%. Additionally, visible blemishes and spots improved by 17.43% after 4 weeks of use. Further testing on 23 adult women (May 14, 2025 – June 12, 2025) showed 38.9% improvement in stratum corneum antioxidant levels, 42.6% in lipid barrier antioxidant levels, and 46.8% in protein structure antioxidant levels.

Usage instructions

Due to the high concentration of Vitamin C, it is recommended to store the product upright in a refrigerator (3–10°C) both before and after opening. Use within 2 months of opening for optimal freshness. To use, attach the dropper and gently shake the bottle from side to side; do not shake vigorously before opening to avoid overflow. If you are using COSRX Blue Peptide serum or cream products, please use them at different times of the day (e.g., one in the morning, one in the evening) to ensure best results.