Everyday care for a bloated gut

Feeling heavy after meals, or bloated more days than not? Duolac's 위청장쾌 (Wi-Cheong-Jang-Kwae) is a daily probiotic made specifically for a gut that often feels bloated and uncomfortable, from Korea's World-Class Product probiotic brand.

World-Class Product brand, Korea's Ministry of Trade, Industry and Energy (2024).

Rated 4.9 out of 5

Here's what customers on Duolac's Korean store say:

“If your gut is on the weak side, I really recommend it. It suits me even better than Duolac Gold!”

“I sit at a desk for long hours and often felt bloated. I've taken it for just over a month and I'm going to keep buying it.”

“I'm a student who sits and studies for hours. Taking it consistently has helped.”

Rating from Duolac's SmartStore (as of 10 Aug 2023). Reviews from Duolac's Korean store, translated by Gochujar. Individual results may vary.

Tried the rest? This is where people land.

Looking for a probiotic for a gut that often feels bloated? One you can keep in your bag? One made with 100% Korean strains? It's all here, in just two capsules a day.

It's there for you when your gut feels bloated, when big meals and late dinners leave you uncomfortable, and when you don't move much and your gut feels it.

Two capsules. Once a day.

A premium probiotic designed around one job: looking after a bloated, sluggish gut.

It uses two probiotic strains, 100% Korean in origin and both on the US FDA GRAS register*, in a science-backed formula for a bloated gut.

Duolac's patented dual coating (Korea, US, EU, Japan, China) helps the cultures reach your gut alive. Enzyme food from Australia goes in as a sub-ingredient, all in a plant-based capsule.

*GRAS relates to ingredient safety, not to health benefits.

Made for you if…

You feel bloated most days, or big meals and late dinners leave your gut heavy.

You sit for long hours at a desk, often eat out or rely on instant food.

Bloating comes with irregular bowel movements.

You want an everyday probiotic you can keep on hand.

Specialists, not generalists

Before you choose a probiotic, check who designed it. Duolac has spent 30 years researching one thing: probiotic strains of Korean origin.

Two strains, both from Korea

Chosen with Korean guts in mind.

Streptococcus thermophilus CBT-ST3, originally isolated from Koreans.

Lactiplantibacillus plantarum CBT-LP3, originally isolated from kimchi (a patented strain).

47 scientists behind every capsule

Duolac doesn't buy in its strains. It develops them itself: sourced from healthy Koreans and traditional Korean fermented foods, safety-verified in human trials with Korean adults, and researched strain by strain with next-generation genome sequencing.

That work adds up to 107 patents, 35 human trials, 124 published papers and 231 research achievements in total.

Cell Biotech figures, as of 2025.

What does “CBT” mean?

Every probiotic strain has a name, just like people do. CBT stands for Cell Biotech, the company behind Duolac, and marks strains Duolac developed itself. When you see CBT, you know where it came from.

Safety you can check for yourself

Probiotics are live cultures, so safety comes first. Duolac uses only strains on the US FDA GRAS (Generally Recognized As Safe) register, and holds more GRAS-listed strains than any other company in the world (as of February 2024).

GRAS is the FDA's safety recognition for food ingredients. It relates to safety, not to health benefits.

Verified at every level

Duolac doesn't just say its probiotics are safe. It shows you the paperwork.

Its strains' functionality is recognized under Korea's MFDS health functional food standards. The strains are deposited with Germany's DSMZ and the Korean Collection for Type Cultures (KCTC), and the DNA sequence of each one is registered with the US NCBI.

Duolac exports to 55 countries and was Korea's No.1 probiotic exporter 11 years running (2013–2023). It's also a World-Class Product brand, named by Korea's Ministry of Trade, Industry and Energy (2024).

Quality certifications: GMP, CODEX HACCP, ISO 9001, MUI Halal, OK Kosher, BPOM. Halal and kosher apply to specific ingredients or strains.

From strain to your door, all Duolac

No outsourcing, no shortcuts. Duolac runs every step itself, to global standards: strain development and research, culturing and isolation, patented coating and freeze-drying, strain blending, finished product manufacturing, quality testing, and delivery and customer service.

A formula built for a bloated gut

Cell Biotech's Microbiome Institute used years of strain-analysis data to design this blend specifically for a gut that often feels bloated: 100% lactic acid bacteria, from S. thermophilus CBT-ST3 and L. plantarum CBT-LP3.

Why the blend matters

Each strain has its own home in the gut and its own growth pace, and our gut flora shifts as we age. Duolac designs every product's blend around that, so each strain can do its job.

With enzyme food from Australia

Alongside the probiotics, every capsule includes an enzyme food ingredient (Aspergillus oryzae fermented powder and Aspergillus niger culture, with pineapple and papaya extracts), plus fructooligosaccharides, a prebiotic that feeds good bacteria.

A plant-based capsule

The capsule shell is plant-based (HPMC), so it's easy to feel good about. Just two capsules with a glass of water.

Protected all the way down

A probiotic only helps if it survives the trip. Duolac's patented dual coating wraps each culture in a tough matrix of protein and polysaccharide, shielding it from stomach acid and bile so it reaches your gut alive. It's patented in the EU, US, Korea, China and Japan.

Up to 221× more reach the gut

The coating makes a real difference. In a human study, people taking dual-coated probiotics had up to 221 times more of the strain in their gut (L. rhamnosus CBT-LR5) than those taking uncoated probiotics.

Randomized, double-blind, controlled study of 40 adults over 2 weeks. Source: “Effect of double-coated probiotic formulation on functional constipation in the elderly.” The study used other Duolac strains; individual results may vary.

No fridge? No problem.

Duolac's CBT strains were confirmed to survive from −70°C all the way up to 40°C, so they're happy at room temperature: in your bag, at your desk or on a trip. Under the microscope, the cultures kept multiplying over time.

Tested by the Korea Functional Food Research Institute and Korea Food Research Institute (samples provided by Cell Biotech).

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