How much should I apply, and how long should it stay on?

After cleansing, apply 2–3 drops while avoiding your eye and lip areas. Massage for about one minute and rinse thoroughly; do not leave it on beyond about one minute.

How often should I use this exfoliating treatment?

Use it once or twice weekly, adjusting the frequency to your skin’s tolerance and condition.

Should I use it during the day or at night?

Nighttime use is recommended. If you use it during the day, protect your skin and apply sunscreen.

What does the “30” in the product name refer to?

It refers to the formula’s 30% ACID 4 blend of AHA, BHA, PHA and LHA.

What color and consistency does the serum have?

It is charcoal-colored and has medium-high viscosity.

Which skin concerns is this exfoliant designed to address?

It is intended for rough or flaky texture, dullness, excess sebum and clogged-pore concerns, including blackheads, whiteheads and enlarged-looking pores.

What precautions should I follow when trying this concentrated exfoliant?

Patch test before use. Tingling may occur; stop using it if irritation develops, and do not apply it to wounded or damaged skin. Keep contact to about one minute. Nighttime use is recommended, with sunscreen and sun protection advised if used during the day.

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ISNTREE

Hyper Acid4 AHA BHA PHA LHA 30 Serum

What it is: A concentrated, rinse-off chemical exfoliant that combines AHA, BHA, PHA and LHA to smooth uneven-looking texture and address excess oil and congestion.

30% AHA + BHA + PHA + LHA blend
One-minute rinse-off format
Smoother, more even-looking texture
Targets excess oil and congestion

Net weight: 20 ml

30% AHA + BHA + PHA + LHA blend

One-minute rinse-off format

Smoother, more even-looking texture

Targets excess oil and congestion

Main active: 4-HA Complex
Intensity: Advanced

PRODUCT DETAILS

Although it’s called a serum, this is a rinse-off exfoliating treatment. It combines a 30% ACID 4 blend of AHA, BHA, PHA and LHA to remove dead surface cells and help rough, uneven-looking texture appear smoother.

The acid quartet gives each type a useful role: AHA focuses on surface exfoliation, BHA on sebum and pores, PHA on exfoliation with hydration support, and LHA on gentler exfoliation. Together, they help address excess surface oil and the look of blackheads, whiteheads and enlarged-looking pores.

The charcoal-colored formula has a medium-high viscosity. Niacinamide supports more even-looking texture and helps control excess sebum, while allantoin provides moisturizing and soothing support. Charcoal powder helps clarify the look of pores and balance oil and moisture.

This is a focused choice for rough or flaky texture, dullness, excess sebum or clogged-pore concerns. Its short, rinse-off format distinguishes it from a leave-on serum.

Learn more

GOES WELL WITH

2-Step Greenery Calming Ampule Mask$15.99 USD

1+1 Toning C Vita Shot Ampoule$28.99 USD

1% Oligo Hyaluronic Acid Toner$15.99 USD

100 Collagen Reedle Shot Stick Pouch$9.49 USD

100 PRO CICA Reedle Shot Stick Pouches$9.49 USD

100 Reedle Shot Stick Pouch$8.09 USD

100 RETI-A Reedle Shot$9.49 USD

1025 Dokdo Cleanser$11.99 USD

A concentrated rinse-off blend focused on smoother-looking texture, excess oil and congested-looking pores.

Smoother, more even-looking texture
A clearer look for congested pores
Less excess surface oil

Key Ingredients

Four overlapping translucent gel-like forms in pale sage, peach, blush, and ivory, accented by clear droplets on a softly lit warm pink surface.

4-HA Complex

A four-acid exfoliating complex that helps loosen dead surface cells for smoother-looking texture.

Niacinamide

Helps visibly brighten uneven tone and support the skin barrier.

Three oversized translucent, softly faceted glass crystals arranged on a pale lavender stage above a blush background with a small coral accent.

Allantoin

Helps soothe and soften dry, rough-feeling skin.

Charcoal Powder

An adsorbent cosmetic powder that helps collect excess oil, impurities and loosened dead-skin buildup during cleansing or exfoliation.

Rounded pool of glossy black serum on a pale background.

Concerns & Benefits

Your Concerns

1
Uneven Texture
Rough or flaky texture can leave the surface looking uneven and dull.
2
Blackheads Whiteheads
Blackheads and whiteheads can leave pores looking visibly congested.
3

How To Use

1Use at night once or twice weekly, adjusting the frequency to your skin’s tolerance and condition.
2After cleansing, apply 2–3 drops to your skin, avoiding the eye and lip areas.
3Massage it over your skin for about one minute; do not leave the treatment on beyond about one minute.
4Rinse thoroughly with lukewarm water.
5If you use it during the day, protect your skin and apply sunscreen.

Dropper lifted above the open bottle with a black serum drop at the tip.

Frequently asked questions

Is this a leave-on serum or a rinse-off exfoliant?

It is a rinse-off exfoliating treatment, despite the serum name. Massage it over your skin for about one minute, then rinse thoroughly with lukewarm water.

Keep learning

Customer reviews

CNP Laboratory

2-Step Greenery Calming Ampule Mask

Ampule-first sheet mask care for gentle hydration and a fresh, refined-looking finish.

5 treatments$15.99 USD

Cell Fusion C

1+1 Toning C Vita Shot Ampoule

15% vitamin C and sponge micro-spicules for brighter, smoother, hydrated-looking skin.

20g + 20g$28.99 USD

Onething

1% Oligo Hyaluronic Acid Toner

Lightweight hydration with 1% hydrolyzed sodium hyaluronate.

150 ml$15.99 USD

VT COSMETICS

100 Collagen Reedle Shot Stick Pouch

Beginner-friendly texture care with moisture, firmness and a refreshing, non-sticky finish.

2 ml × 10 sachets$9.49 USD

VT COSMETICS

100 PRO CICA Reedle Shot Stick Pouches

Daily texture care with soothing hydration, one travel-friendly pouch at a time.

2 ml × 10 pouches$9.49 USD

VT COSMETICS

100 Reedle Shot Stick Pouch

A travel-size evening booster for smoother-feeling, more refined-looking skin.

2 mL × 10$8.09 USD

VT COSMETICS

100 RETI-A Reedle Shot

A beginner-friendly evening serum for smoother-looking texture, refined-looking pores and radiant skin.

2 ml × 10 sachets$9.49 USD

ROUND LAB

1025 Dokdo Cleanser

Creamy, slightly acidic foam for a comfortable cleanse

150 ml$11.99 USD

ISNTREE Hyper Acid4 AHA BHA PHA LHA 30 Serum | Sleepy Hello

ISNTREE

Hyper Acid4 AHA BHA PHA LHA 30 Serum

What it is: A concentrated, rinse-off chemical exfoliant that combines AHA, BHA, PHA and LHA to smooth uneven-looking texture and address excess oil and congestion.

30% AHA + BHA + PHA + LHA blend
One-minute rinse-off format
Smoother, more even-looking texture
Targets excess oil and congestion

Net weight: 20 ml

30% AHA + BHA + PHA + LHA blend

One-minute rinse-off format

Smoother, more even-looking texture

Targets excess oil and congestion

Main active: 4-HA Complex
Intensity: Advanced

PRODUCT DETAILS

This is a focused choice for rough or flaky texture, dullness, excess sebum or clogged-pore concerns. Its short, rinse-off format distinguishes it from a leave-on serum.

Learn more

GOES WELL WITH

2-Step Greenery Calming Ampule Mask$15.99 USD

1+1 Toning C Vita Shot Ampoule$28.99 USD

1% Oligo Hyaluronic Acid Toner$15.99 USD

100 Collagen Reedle Shot Stick Pouch$9.49 USD

100 PRO CICA Reedle Shot Stick Pouches$9.49 USD

100 Reedle Shot Stick Pouch$8.09 USD

100 RETI-A Reedle Shot$9.49 USD

1025 Dokdo Cleanser$11.99 USD

A concentrated rinse-off blend focused on smoother-looking texture, excess oil and congested-looking pores.

Smoother, more even-looking texture
A clearer look for congested pores
Less excess surface oil