COSRX Advanced Pure Vitamin C 23% Serum — 0.7oz Brightening Serum with Vitamin E & Glutathione, Fast-Absorbing

COSRX Advanced Pure Vitamin C 23% Serum is a high-concentration, lightweight vitamin C booster formulated with vitamin E and glutathione to brighten dull skin and support a more even tone.

This serum combines 23% pure ascorbic acid with supportive antioxidants to deliver a potent brightening and radiance-boosting treatment in a non-sticky, fast-absorbing formula. The updated version removes the characteristic scent of the original while keeping the same active concentration, and it’s designed for short, targeted applications—2–3 drops—either once or twice daily. Store refrigerated after opening to slow oxidation and always pair with SPF during daytime use.

How does this serum fit into my morning routine?

Use the serum after cleansing and lightweight toner, before moisturizer and sunscreen. Apply a small amount so other products layer smoothly and the vitamin C can work without pilling or dilution.

• Shake 1–2 times and dispense 2–3 drops onto fingertips.
• Pat gently over the face and avoid direct eye contact.
• Follow with SPF 30+ during the day to protect treated skin.

Can this be used at night and around the eye area?

The formula is suitable for evening use and can be applied under the eye area with care. Because it contains a high percentage of ascorbic acid, patch testing is recommended to confirm tolerance.

• Apply 2–3 drops after cleansing and before heavier oils or creams.
• Gently tap under-eye skin, avoiding direct contact with the eyes.
• If irritation occurs, discontinue and consult a healthcare professional.

What do the added ingredients—vitamin E and glutathione—do here?

Vitamin E and glutathione support the antioxidant action of pure vitamin C, helping stabilize the formula and broaden its activity against environmental stressors. Together they contribute to a smoother, more even-looking complexion without adding heaviness.

• Vitamin E (tocotrienol) complements vitamin C’s antioxidant effects.
• Glutathione aids in evening out skin tone and reducing dullness.
• The lightweight base finishes hydrating, not sticky.

How should I store and test the serum to keep it effective?

Because ascorbic acid can oxidize, proper storage preserves potency. Refrigeration after opening and brief patch testing help ensure safety and freshness over the product’s use.

• Store in the fridge after opening to slow oxidation.
• Do a patch test on the body and wait 24 hours before full-face use.
• Avoid using with highly acidic or strong exfoliating actives unless advised by a dermatologist.

Who is this for: COSRX Advanced Pure Vitamin C 23% Serum suits people seeking a potent, fast-absorbing vitamin C treatment to target dullness, uneven tone, and early signs of aging. It’s aimed at users comfortable with a high-strength ascorbic acid formula who will follow storage instructions, perform a patch test, and use sunscreen when applying during the day. Those with sensitive skin or who use multiple strong exfoliants should proceed cautiously and consider consulting a skincare professional.