COSRX Advanced Pure Vitamin C Serum 23% (0.7 oz) — Brightening with Vitamin E & Glutathione

COSRX Advanced Pure Vitamin C 23% Serum is a lightweight topical booster that combines high-concentration ascorbic acid with vitamin E and glutathione to help brighten dull skin and target uneven tone.

This serum delivers a potent 23% pure vitamin C (ascorbic acid) formula in a non-sticky texture designed for daily layering in your skincare routine. The upgraded version removes the original scent while preserving the active concentration and adds a three-way antioxidant blend—tocotrienol (a form of vitamin E) and glutathione—to support overall radiance and antioxidant defense. The 0.7 oz dropper bottle is formulated for careful use: shake before application, store chilled after opening, and pair with SPF during daytime wear.

How should I use this high-strength vitamin C serum safely?

Start slowly and perform a patch test to confirm skin tolerance, then introduce the serum into your AM or PM routine one to two times daily. Apply just a few drops to clean, dry skin and follow with moisturizer; during the day, always finish with SPF 30 or higher. Store the bottle in the refrigerator after opening to slow oxidation and keep the formula stable.

• Shake 1–2 times before use to ensure even texture.
• Use 2–3 drops on face; can be applied under the eye area cautiously.
• Apply sunscreen for daytime use to protect treated skin.
• Refrigerate after opening to maintain potency.

What results can I reasonably expect and when?

Visible improvements such as a brighter complexion and a reduction in the appearance of dullness or uneven tone may appear with consistent use over weeks. Because this is a high-concentration ascorbic acid serum, early benefits often include improved skin radiance and a more even-looking surface; longer-term benefits depend on routine consistency and sun protection. Individual response varies by skin type and prior product use.

• Initial glow can appear within 2–4 weeks for many users.
• Reduction in pigment irregularities typically needs several weeks to months.
• Results are enhanced when combined with daily SPF and supportive skincare.

Is this serum suitable for sensitive or reactive skin?

Because the formula contains 23% pure ascorbic acid, it is potent and may cause irritation on very sensitive or reactive skin types. A patch test is recommended (wait 24 hours) before applying to the full face. If you experience stinging, redness, or discomfort, discontinue use and consult a healthcare professional; consider lower-concentration vitamin C alternatives if sensitivity persists.

• Patch test on the inner arm or behind the ear for 24 hours first.
• Reduce frequency (every other day) while skin builds tolerance.
• Avoid contact with open wounds or broken skin; stop if irritation occurs.

How does the antioxidant blend in this serum help my routine?

The combination of pure vitamin C, a tocotrienol form of vitamin E, and glutathione creates complementary antioxidant activity that supports protection against free-radical stress and helps improve the skin’s overall appearance. While vitamin C primarily targets brightness and antioxidant support, tocotrienol aids in stabilizing the formula and contributing to barrier resilience, and glutathione is included to help even out skin tone. Together they form a targeted support system for daytime and nightly care when used appropriately.

• Ascorbic acid: delivers concentrated brightening and antioxidant action.
• Tocotrienol (vitamin E): supports skin resilience and formula stability.
• Glutathione: assists in improving the look of uneven pigmentation.

Who this product is for: COSRX Advanced Pure Vitamin C 23% Serum is aimed at people comfortable with high-strength active skincare who want to boost radiance, address early signs of uneven tone, and layer a concentrated vitamin C underneath moisturizing and protective steps. It suits those familiar with active ingredients, willing to perform patch tests, and committed to daily sun protection; those with highly reactive or eczema-prone skin may prefer lower-strength vitamin C options first.