COSRX Refresh AHA/BHA Vitamin C Booster Serum 30ml

COSRX Refresh AHA/BHA Vitamin C Booster Serum: Three Actives for Texture and Tone

COSRX's Refresh AHA/BHA Vitamin C Booster Serum combines three of the most effective brightening and exfoliating actives into a single serum: ascorbic acid (vitamin C), glycolic acid (AHA), and salicylic acid (BHA). At $24.96 for 30ml, this is aggressively priced for a triple-active formulation. Most brands sell each active separately; COSRX's approach is consolidated routine simplification.

The trade-off with combined-active formulations is concentration limitations (you can't have high concentrations of all three actives in the same formula without severe irritation) and pH conflicts (vitamin C prefers pH 3.5 while BHA needs pH 4 for activity). COSRX has formulated this at a compromise pH around 3.5 to 4, which means moderate activity for each active but genuine functionality across the board. For users who want multi-pronged routine simplification, this delivers.

What It Does

Ascorbic acid brightens and provides antioxidant protection. Glycolic acid (AHA) exfoliates the skin surface, fading pigmentation and smoothing texture. Salicylic acid (BHA) penetrates pores to address congestion and blackheads. The combined action addresses both surface pigmentation and pore concerns. Over 4 to 8 weeks of use (typically at every-other-day application), visible brightening, texture smoothing, and reduced pore appearance.

Who It's For

• Multi-concern skin: Primary target. Pigmentation plus pores plus texture.
• Routine simplification seekers: Three products in one.
• Active-experienced users: Not a starter serum; pre-acclimated skin recommended.
• Value shoppers: Three actives at single-active pricing.
• Combination skin with uneven tone: Addresses both oily and pigmented areas.

Key Specs

• Volume: 30ml
• Price: $24.96
• Hero actives: ascorbic acid (vitamin C), glycolic acid (AHA), salicylic acid (BHA)
• Texture: lightweight serum
• pH: approximately 3.5 to 4
• Fragrance: very mild

How to Use

Start every other evening, moving to nightly if tolerated. Apply 2 to 3 drops to clean dry skin after toner. Wait 15 minutes before next step, which should be a calming or hydrating layer (not another active). Always follow with sunscreen the next morning. Do not layer with retinol, aggressive BHA, or other acids on the same evening.

FAQ

Will it sting?

Initial applications: mild to moderate tingling for 30 to 60 seconds. This is normal for active serums at this pH. If stinging is severe or lasts longer than 5 minutes, the product is too strong for your skin; step down to a single-active serum first.

Can I use it every day?

For beginners, no. Start every other evening. After 3 to 4 weeks if tolerating well, move to nightly. Don't rush the ramp-up; barrier damage from aggressive active use is difficult to reverse.

How does it compare to The Ordinary AHA/BHA Peel?

The Ordinary's peel is a rinse-off weekly treatment at much higher acid concentrations. COSRX is a leave-on daily-use serum at lower concentrations. For intensive weekly treatment: The Ordinary. For daily gradual improvement: COSRX.

Should I use this AM or PM?

PM only. Vitamin C plus AHA plus BHA increases sun sensitivity. Always apply SPF 50+ the next morning. Some users split: vitamin C AM and AHA/BHA PM, using different products. This combined serum is PM-only.

Safe during pregnancy?

No. Salicylic acid at this concentration is generally avoided during pregnancy. Skip during pregnancy and return post-partum.

Related Products

Follow with COSRX Hydrium Moisture Cream as the calming, sealing moisturizer. Browse the full COSRX collection or related: Korean exfoliants, vitamin C products.