BHA Blackhead Power Liquid
The Product That Built a Brand
Verified reviewer
Pros & cons.
- +Radically minimalist 11-ingredient formula where every ingredient serves a clear purpose
- +4% betaine salicylate provides effective BHA exfoliation with significantly less irritation than salicylic acid
- +68% willow bark water base adds anti-inflammatory support beyond standard water-based formulas
- +Fungal acne safe — no oils, fatty acids, or Malassezia-feeding esters
- +Fragrance-free, alcohol-free, silicone-free, and vegan-friendly
- +Niacinamide and panthenol complement the exfoliation with sebum regulation and hydration
- +Over 12 years of market validation with 30,000+ user reviews confirming consistent performance
- −Results require patience — visible improvement takes 2-4 weeks of consistent use
- −Too gentle for users with stubborn blackheads who need stronger exfoliation
- −Basic packaging with no pump or dropper makes precise dispensing difficult
- −Some users experience a purging period of 1-2 weeks before skin improves
- −100ml bottle runs out within 2-3 months and no larger size option exists
The full review.
In 2013, Jun Sang Hun had a problem. His sensitive skin needed BHA exfoliation for blackheads, but every salicylic acid product on the market caused redness and flaking. He made his own. The BHA Blackhead Power Liquid was COSRX’s first product and the reason the brand exists. Twelve years later, the formula has barely changed, which proves it works.
The ingredient list has eleven items. This is not a typo. While thirty to fifty ingredients are standard in an industry of complex serums, COSRX chose simplicity. Every ingredient has a purpose. Willow bark water is the base. Betaine salicylate is the exfoliant. Niacinamide provides brightening. Panthenol and hyaluronic acid provide hydration. A few texture agents finish it.
The star ingredient is 4% betaine salicylate, which differs from 4% salicylic acid. Betaine salicylate pairs salicylic acid with betaine, an amino acid derivative that acts as a humectant. This allows BHA exfoliation with less irritation. A 2025 study in RSC Medicinal Chemistry found that betaine salicylate showed lower cytotoxicity than salicylic acid, better anti-inflammatory performance, and superior clinical outcomes for acne, oil control, and barrier function in a 28-day trial. The trade-off is gentler exfoliation per application, so you need patience. This product does not transform skin overnight.
The 68% willow bark water base adds sophistication. Willow bark contains salicin, a natural salicylic acid precursor, and anti-inflammatory compounds. It does not convert efficiently to salicylic acid on the skin, but it provides soothing benefits that complement the betaine salicylate. Calling this a dual-source BHA approach is technically accurate but generous; the willow bark is a supportive player rather than a co-star. Using it as the primary solvent instead of purified water is a thoughtful choice.
On the skin, this liquid feels like water with a slight silky viscosity. It does not sting or tingle. If you use a Western 2% salicylic acid product, you may be skeptical. The “bite” is not the point. Betaine salicylate works gently and accumulates effects over time. By week two or three, pores look cleaner, sebaceous filaments are less visible, and skin texture improves.
Some users experience purging during the first one to two weeks—small breakouts in previously congested areas. This is normal and shows the exfoliant is clearing existing congestion. If you break out in non-congested areas, it is likely an adverse reaction rather than purging.
The 2% niacinamide is a smart addition. It regulates sebum production to address the root cause of blackheads alongside the BHA. It also provides mild brightening over weeks of use. Panthenol and sodium hyaluronate keep skin hydrated during exfoliation, preventing the tightness and flaking common with standard BHA products.
The formula is fungal acne safe. It contains no oils, fatty acids, or esters that feed Malassezia yeast. For those with both blackheads and pityrosporum folliculitis, this is one of the best options.
Limitations: if you have deep blackheads and use stronger exfoliants, this may feel underwhelming. It is for gentle, consistent maintenance, not aggressive clearing. The packaging is basic—a simple bottle with a hole in the cap, no pump or dropper. Dispensing is imprecise, and you may pour out too much.
At twenty-five dollars for 100 milliliters, the value is excellent. A few drops cover the face, and one bottle lasts two to three months with regular use. With over a decade of market validation, 30,000+ reviews, and a stable formulation, it is a confident purchase.
This liquid will not wow you on the first night. It does not feel dramatic. But use it consistently for a month, and your pores will look cleaner and your texture smoother without skin irritation. That is the COSRX philosophy in one bottle—the reason Jun Sang Hun built a brand around it.
Formula
Ingredient analysis.
Full INCI list · pH 4
Salix Alba (Willow) Bark Water, Butylene Glycol, Betaine, Niacinamide, Betaine Salicylate, 1,2-Hexanediol, Sodium Hydroxide, Sodium Hyaluronate, Panthenol, Xanthan Gum, Ethyl Hexanediol
Skin match.
The science.
The Science
Betaine salicylate is the core innovation here. This compound combines salicylic acid with betaine (trimethylglycine), a natural osmolyte. A 2025 study in RSC Medicinal Chemistry by Wang et al. tested betaine-salicylic acid cocrystals in vitro and clinically. The results show betaine salicylate has an IC50 more than three times that of pure salicylic acid, making it less cytotoxic. In a 28-day clinical trial, betaine salicylate beat salicylic acid on several endpoints: it reduced transepidermal water loss by 43.45% versus 21.90%, reduced porphyrins (a marker of bacterial acne activity) by 40.80% versus 26.16%, and reduced acne lesions by 37.51% versus 24.01%.
The willow bark water base provides salicin, a beta-glucoside of salicyl alcohol. Salicin is a natural precursor to salicylic acid, but topical conversion is inefficient because enzymatic hydrolysis happens mostly in the gut, not on the skin. However, willow bark extract has independent anti-inflammatory activity by inhibiting cyclooxygenase-2 (COX-2) and pro-inflammatory cytokines. This provides soothing benefits that complement the exfoliating action of betaine salicylate.
The pH of approximately 4.0 targets betaine salicylate instead of free salicylic acid. Pure salicylic acid needs a pH of 3.0-3.5 for best penetration, but betaine salicylate works well at the higher pH range of 3.8-4.2. This higher pH reduces irritation potential without cutting exfoliating efficacy, creating a wider therapeutic window for sensitive skin.
References
- Betaine-salicylic acid cocrystal for enhanced skincare and acne treatment — RSC Medicinal Chemistry (2025)
Dermatologist Perspective
Board-certified dermatologists view betaine salicylate as a viable alternative to standard salicylic acid for patients irritated by conventional BHA products. The lower cytotoxicity and higher pH of betaine salicylate formulations suit sensitive skin patients who still need chemical exfoliation for blackhead management. Dermatologists often suggest starting BHA use two to three times per week and increasing frequency as tolerance builds. Including niacinamide and panthenol follows dermatological best practices to minimize exfoliation-related barrier disruption. For patients with concurrent fungal acne, the clean ingredient list makes this one of the few BHA options dermatologists can recommend without Malassezia triggers.
Where it fits in your routine.
Cleanse and dry your face. Put a small amount (about a dime-sized pool) on a cotton pad or your fingertips. Sweep it across your face, focusing on blackheads, congestion, and enlarged pores. Avoid the eye area and broken skin. Wait 15-20 minutes before your next step so the BHA works at its intended pH. Follow with a hydrating toner, moisturizer, and sunscreen (AM). Use 2-3 times per week initially, then increase to daily use as your skin tolerates it.
At $25 for 100ml, this is one of the most cost-effective BHA exfoliants available, backed by a decade-plus track record. Using a few drops per application makes the bottle last two to three months with regular use, keeping the per-use cost under a dollar. Only one size exists, so no bulk purchase offers better per-unit value. With over 30,000 reviews and a formula that has stayed essentially unchanged since 2013, the price reflects proven efficacy instead of novelty or brand premium. The value is straightforward: this costs less per month than most BHA alternatives and delivers gentler, well-validated results.
This works for anyone with blackheads, enlarged pores, or dull texture who finds standard salicylic acid products too harsh. Sensitive and combination-to-oily skin types benefit most. If you have fungal acne and need a BHA exfoliant, this is one of the safest options.
Skip this if you need aggressive exfoliation for stubborn, deep blackheads; it is too gentle. Very dry skin types may not need BHA exfoliation and could experience dehydration. If you want immediate, dramatic results, the gradual approach of betaine salicylate may not meet your expectations.
Product details.
Thin, slightly viscous liquid with a silky-water consistency. It is not greasy or slimy. The liquid spreads easily and absorbs within a few minutes.
It is unscented. Some users notice a faint, slightly citric or mild chemical smell that vanishes within seconds. It has no added fragrances.
Simple plastic bottle uses a small hole-type cap for dispensing. It is functional but basic, lacking a pump, dropper, or precision applicator. The 100ml size is standard for K-beauty liquid exfoliants.
The liquid feels like silky water on first use. It does not sting, burn, or tingle, unlike most Western BHA products. Skin feels slightly smoother after the first application. Some users experience mild purging (small breakouts in congestion-prone areas) during the first 1-2 weeks. This is a normal sign the exfoliant works to clear existing pore congestion.
2-3 months with use 3-4 times per week on the face
12 months
All Year
The backstory.
COSRX founder Jun Sang Hun created this product out of personal necessity — his sensitive skin could not tolerate the harsh BHA treatments available at the time. The BHA Blackhead Power Liquid became the brand's debut product in 2013, and its success proved there was a massive market for effective-but-gentle exfoliation. It essentially launched the Korean BHA category for international audiences.
About COSRX
Established Brand (5–20 years)COSRX was founded in 2013 in South Korea, and the BHA Blackhead Power Liquid was the brand's very first product — the one that launched the entire company. Over a decade later, COSRX has become one of the most widely trusted K-beauty brands globally, with a philosophy of 'Cosmetics + Rx' combining clinical-grade formulations with accessible pricing.
Common myths.
4% betaine salicylate is weaker than 2% salicylic acid; this product does not work.
Betaine salicylate works differently than free salicylic acid. A 2025 study in RSC Medicinal Chemistry shows betaine salicylate provides superior anti-inflammatory performance, better TEWL reduction, and more effective acne reduction than salicylic acid in a 28-day clinical trial. Each application exfoliates more gently, but the effect accumulates with consistent use.
Willow bark extract is just another name for salicylic acid.
Willow bark contains salicin, a salicylic acid precursor, rather than salicylic acid. The skin does not convert topically applied salicin into salicylic acid efficiently; salicin requires metabolism first. However, willow bark water provides anti-inflammatory and soothing benefits through pathways independent of salicylic acid.
FAQ.
What is the pH of COSRX BHA Blackhead Power Liquid?
The pH is about 4.0. This is slightly higher than typical salicylic acid products (pH 3.0-3.5) but fits betaine salicylate, which works well at pH 3.8-4.2. This higher pH makes the exfoliation gentler.
Is COSRX BHA safe for fungal acne?
Yes — this BHA exfoliant is one of the few free of Malassezia-feeding ingredients. The 11-ingredient formula contains no oils, fatty acids, or esters that trigger fungal acne. This makes it a safe option for those with pityrosporum folliculitis.
How long does it take to see results from COSRX BHA?
Most users feel immediate smoothness after the first application. Blackheads and sebaceous filaments visibly reduce within 2-4 weeks of consistent use (3-4 times per week). Pore refinement and texture improvement show results over 4-8 weeks. Some users experience a brief 1-2 week purging period before skin improves.
Can I use COSRX BHA with retinol?
Yes, but use them on alternate evenings instead of layering them. Both are active treatments that increase cell turnover. Using BHA one evening and retinol the next prevents over-exfoliation while keeping the benefits of both. This product's gentle betaine salicylate makes it more compatible with retinoid schedules than stronger BHA products.
Is 4% betaine salicylate the same as 4% salicylic acid?
No. Betaine salicylate combines betaine and salicylic acid. Therefore, 4% betaine salicylate has less free salicylic acid than a 4% salicylic acid product. It has about 2% salicylic acid exfoliating strength, but recent clinical research shows it causes less irritation and has better anti-inflammatory performance.
Should I use a wait time after applying COSRX BHA?
Wait 15-20 minutes after application before your next skincare step for optimal results. This lets the BHA work at its intended pH of ~4.0 without neutralization from higher-pH products. Some dermatologists note wait times matter less for gentler BHA products like this one.
Can I use COSRX BHA every day?
Use this 2-3 times per week and check skin tolerance for 2-3 weeks. Since betaine salicylate is gentler than pure salicylic acid, many users eventually use it daily without irritation. Most people do not need daily use; 3-4 times per week manages blackheads well.
Community
What the community says.
"Gentle enough for sensitive skin while still effectively clearing blackheads"
"Lightweight, non-drying formula that does not strip the skin"
"Short, clean 11-ingredient list with no unnecessary fillers"
"Noticeable improvement in skin texture and pore appearance over time"
"Excellent value for money at the price point"
"Fungal acne safe formula"
"Results are gradual and require weeks of consistent use to become visible"
"Too gentle for users accustomed to stronger 2% salicylic acid products"
"Some users experience a purging period of 1-2 weeks before improvement"
"Plain packaging with no pump or dropper makes dispensing imprecise"
"100ml bottle can run out quickly with daily full-face use"
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