The AHA BHA PHA LHA 35 Peel

For a decade, COSRX has been the brand that whispered where others shouted. The BHA Blackhead Power Liquid. The AHA Whitehead Power Liquid. These were products that said trust the process, be patient, gentle daily exfoliation will get you there. And then, in late 2023, COSRX walked into the room with a pink gel containing 35 percent acid and essentially said: actually, sometimes you need to turn the volume up.

The AHA BHA PHA LHA 35 Peel is a four-acid chemical peel that does not pretend to be anything other than what it is — a serious exfoliating treatment for people who know what they are doing with acids. The 35 represents a combined acid concentration that includes nearly 28 percent AHA (glycolic, lactic, mandelic, and citric), 5 percent PHA (gluconolactone), 2 percent BHA (salicylic acid), and a trace 0.02 percent LHA (capryloyl salicylic acid). Each acid type operates at a different molecular size and solubility, and together they create something genuinely compelling: multi-depth exfoliation that addresses the skin surface, the mid-stratum corneum, and the interior of pores simultaneously.

Glycolic acid, the smallest and most penetrating AHA, drives the deep resurfacing. Lactic acid provides broader, more even exfoliation with added humectant properties. Mandelic acid, with its larger molecular size, contributes antimicrobial action and gentler surface-level peeling. Gluconolactone exfoliates while moisturizing. Salicylic acid dives into the oil-filled pores where water-soluble acids cannot follow. And capryloyl salicylic acid — the LHA that earns this peel its fourth initial — is even more lipophilic than standard salicylic acid, targeting the deepest part of the sebaceous follicle. The theoretical framework is elegant. Each acid has a job. Together, they cover the full depth of what chemical exfoliation can address.

In practice, you feel the 35 percent working. Apply the distinctive pink gel to clean, dry skin and a tingling begins almost immediately, building to a mild sting that peaks around the second or third minute before stabilizing. This is not uncomfortable for anyone experienced with acid products, but it is unmistakable — your skin is being actively exfoliated, and it wants you to know. First-time users should start with three to five minutes and work up to the full ten. Pushing through discomfort is not bravery; it is barrier damage waiting to happen.

After rinsing, the results are gratifyingly immediate. Skin feels polished — not raw or stripped, but genuinely smoother, as if someone has carefully buffed away a layer of dullness that you had stopped noticing was there. The complexion looks brighter and more even. Pores that were clogged feel clearer. Over the course of four to six weekly sessions, the cumulative effect is significant: improved texture, reduced congestion, more even tone, and a clarity that daily-use acid products take much longer to achieve.

The formula earns additional points for what it includes alongside the acids. Panthenol, listed eighth in the INCI — high for a supporting ingredient — provides meaningful barrier repair and soothing during the peel process. Cyanocobalamin, the vitamin B12 responsible for the gel's natural pink hue, contributes skin barrier support without artificial coloring. Allantoin soothes. Hydrolyzed hyaluronic acid provides humectant action. These are not afterthoughts; they are deliberate formulation choices that make the difference between a peel that leaves skin feeling punished and one that leaves it feeling renewed.

The packaging is the product's weakest element. At thirty milliliters, the bottle is small — roughly eight to twelve applications at once per week, giving you two to three months of use. Multiple users have reported leaking issues with the closure mechanism, which is a genuine concern for a product containing high-concentration acids. A more robust, possibly airless pump format would better serve both the formula's stability and the user's bathroom counter.

At nineteen dollars, the price per bottle is reasonable, but the price per use — roughly one-fifty to two-fifty per session — is higher than it initially appears for a K-beauty product. That said, comparable multi-acid peels from Western brands typically cost forty to sixty dollars for similar volumes, so COSRX's positioning remains aggressive on value.

This peel is explicitly not for everyone, and COSRX deserves credit for saying so clearly. If you are new to chemical exfoliation, this is not your starting product. If you have rosacea, eczema, or a compromised barrier, this will make things worse before it makes them better. If you are pregnant, the salicylic acid content warrants a conversation with your doctor. This is a product for people who have spent months building acid tolerance and are ready for the next level — and for those people, it delivers a genuinely professional-grade experience at a fraction of the price.

COSRX's decision to make this product feels like a statement of maturity. The brand is saying: we are not just the gentle daily-acid company anymore. We can formulate at the high end too. The AHA BHA PHA LHA 35 Peel proves the point convincingly. Just make sure your skin is ready for the conversation.

Formula

The Science

The multi-acid approach in this peel leverages the different penetration profiles and mechanisms of four distinct acid categories to achieve comprehensive exfoliation. Glycolic acid (molecular weight 76 Da) is the most penetrating AHA and drives the deepest exfoliation by disrupting ionic bonds between corneocytes. A 2003 study by Kornhauser et al. in the Journal of Cosmetic Dermatology reviewed the cumulative evidence for glycolic acid and confirmed its ability to reduce stratum corneum thickness, stimulate epidermal hyaluronic acid synthesis, and increase dermal collagen density at regular use.

Lactic acid (molecular weight 90 Da) provides complementary AHA exfoliation with a larger molecular size that slows penetration, reducing the risk of uneven acid distribution. Notably, lactic acid has been demonstrated to directly inhibit tyrosinase activity, contributing a brightening mechanism that glycolic acid does not share. Mandelic acid (molecular weight 152 Da), the largest AHA in this formula, limits its action to the uppermost stratum corneum layers while contributing antibacterial activity against Propionibacterium acnes — documented in a 1999 study by Taylor in Dermatologic Surgery.

Gluconolactone (PHA) exfoliates through the same desmosomal disruption as AHAs but with significantly reduced irritation potential. Edison et al. demonstrated in a 1999 study in Cutis that gluconolactone provided anti-aging and exfoliating benefits comparable to glycolic acid while being better tolerated in patients with clinically sensitive skin. Its multiple hydroxyl groups also function as humectants, adding a moisture-retention dimension absent from the AHA components.

Salicylic acid at 2% provides the only oil-soluble exfoliation in the formula. Its ability to dissolve within the sebaceous material filling pores makes it uniquely effective for comedonal acne — a mechanism that the water-soluble AHAs and PHAs cannot replicate. Capryloyl salicylic acid (LHA) extends this intrapore reach with even greater lipophilicity, though at 0.02% its contribution is minimal.

Potassium hydroxide is present as a partial neutralizer — it raises the pH above the extreme acidity that pure glycolic acid would create, converting a portion of the free acid into its potassium salt. This reduces the effective free acid concentration while maintaining enough active acid for therapeutic exfoliation, essentially building a safety margin into the formula that prevents chemical burn while allowing meaningful peel activity.

References

1. Mandelic acid as a treatment for acne: clinical assessment and laboratory studies — Dermatologic Surgery (1999)
2. Comparative effectiveness of glycolic acid and gluconolactone in the treatment of aging skin — Cutis (1999)

Dermatologist Perspective

Board-certified dermatologists note that a 35% multi-acid peel falls within the moderate-strength professional peel range and can deliver genuine resurfacing results at home. Dermatologists appreciate the multi-acid approach for its ability to target different skin depths and pathologies simultaneously — surface texture via AHAs, pore congestion via BHA, and sensitive-skin-compatible exfoliation via PHA. However, dermatologists strongly emphasize that products at this concentration require established acid tolerance and strict adherence to usage frequency limits. Over-use of at-home peels is a common cause of iatrogenic barrier damage seen in dermatology offices. The inclusion of panthenol and allantoin as soothing agents is noted as a responsible formulation choice, and the once-weekly-maximum instruction aligns with dermatological guidance for at-home peels at this concentration.

Guidance

COSRX launched this peel in late 2023 as its most ambitious acid product to date — a significant step up from the brand's popular but gentler AHA Whitehead Power Liquid and BHA Blackhead Power Liquid. It was marketed as a '10-minute glass skin transformation,' targeting experienced acid users who wanted professional-peel-level results at home. The four-acid approach and 35% concentration reflect COSRX's decade of acid formulation expertise being pushed to its most potent expression.

About COSRX Established Brand (5–20 years)

COSRX was founded in 2013 in Seoul and became a subsidiary of Amorepacific in 2023. The brand has deep expertise in acid-based exfoliation, having built its reputation on the AHA 7 Whitehead Power Liquid and BHA Blackhead Power Liquid — some of the most popular acid treatments in K-beauty.

Brand founded: 2013 · Product launched: 2023

Myth vs. Reality

Myth

More acids and higher percentages always mean better results.

Reality

The 35% concentration is genuinely potent, but efficacy depends on formulation balance, pH, and correct usage. Over-using this peel (more than once weekly) or leaving it on too long will damage the skin barrier rather than improve it. The formula includes potassium hydroxide for partial neutralization and panthenol for soothing precisely because raw acid at this concentration would be destructive without these safeguards.

Myth

At-home peels can never match professional chemical peels.

Reality

Professional peels typically use acid concentrations of 20-70% at very low pH values with precise neutralization timing. At 35% total acid content, this peel sits in the moderate-professional range and delivers genuine resurfacing results that many users compare to light in-office peels. The key difference is professional supervision and the ability to customize concentration — but for maintenance between appointments, a well-formulated at-home peel can be highly effective.

FAQ

Common Praise

"Skin feels dramatically smoother and looks brighter after just one use"

"Effective at clearing stubborn texture, congestion, and rough patches"

"Visible pore-minimizing effects within a few weeks of weekly use"

"Natural pink color from vitamin B12 feels luxurious and distinctive"

"Fragrance-free formula with soothing panthenol and allantoin"

Common Complaints

"Stinging and burning during application — expected but uncomfortable for some"

"30ml bottle is small — runs out within a few months with weekly use"

"Packaging reported to leak after a month of use by some buyers"

"Not suitable for sensitive skin or chemical exfoliation beginners"

"Only one size available — no larger value size option"

Appears In

best exfoliant for texture best chemical peel for dullness best k beauty exfoliant best exfoliant for large pores best exfoliant for acne

Related Conditions

texture dullness acne blackheads large pores hyperpigmentation

Related Ingredients

glycolic acid lactic acid salicylic acid gluconolactone mandelic acid