What is Koso?

KO・SO (酵素)
an enzyme, a ferment

“Koso drink | fermented drink using traditional Japanese methods, rich in prebiotic and probiotics. It is also simply called Koso.”

"Koso" is defined as an enzyme or a ferment in Japanese. Koso drink is a traditional enzyme drink created from vegetables, fruits, and plants, which provides abundant probiotics and prebiotics. Koso is popular among young Japanese women, juice cleansers, and individuals who attempt intermittent fasting. Koso has been a healthy and safe dietary supplement in Japan, dating back about 100 years.

History of Koso

Japan has a long history of making fermented foods, such as miso, soy sauce and sake. Fermented foods are essential ingredients in the dietary habits of Japanese people.

"It is said that production and sales began in Japan about 100 years ago. At the time, it was used as a dietary supplement for hard-working and undernourished people but is now used in daily life not only for nutritional support but also for digestive support and intestinal environment improvement It is becoming." see wikipedia

In the past, it wasn't easy to locate enough ingredients to sustain a healthy diet due to the lack of nutrient-dense foods. When Koso was created, it provided many different types of essential nutrients, allowing people to improve their quality of life.

Koso is a century-old traditional Japanese fermented drink.

Advantages of Koso

KOSO is Japan's best-kept health cleansing secret. KOSO contains many different fruits, vegetables, and plant-based ingredients. It contains probiotics, prebiotics, and postbiotics such as acetic acid. All these essential ingredients help improve gut health, which is closely linked to weight loss, skin health, and mental health.

Benefit and Evidence

Koso is a nutritious supplement that has been used for more than 100 years now, and we are some uncovering part of its health benefits today. There are some study the following.

"The current intervention clearly demonstrates that FPE could significantly lower body weight, fat, BMI, TC, LDL-c, TBARS, and harmful bacteria such as E. coli and C. perfringens as well as substantially improved the levels of TEAC, total phenolic content, and beneficial bacteria such as Bifidobacterium and Lactobacillus spp. Moreover, FPE prolonged the LDL-oxidation lag time owing to its antioxidant capacity and thus exhibited a cardioprotective effect. Hence, we hypothesize that FPE might positively regulate the human intestinal flora and thus maintain the balance between the beneficial and harmful bacteria and thereby favor various health benefits of acting as good probiotics. In the future, the mechanism behind the FPE regulatory effect can be examined in various metabolic syndrome and abnormal gastrointestinal diseases."

See: Regulatory efficacy of fermented plant extract on the intestinal microflora and lipid profile in mildly hypercholesterolemic individuals

"The enzyme-food contained abundant functional ingredients, i.e., polyphenols, dietary fiber, and indigestible dextrin. The
enzyme-food indicated high antioxidant activity and suppression of AGE (glycated protein) formation, which is thought to be responsible for the pathogenesis of various lifestyle diseases. The feeding of enzyme-food in rats suggested that the possibilities of body fat reduction, improvement of bowel movements, and improvement of carbohydrate and lipid metabolism. So the products commonly called ‘enzyme-foods’ may be beneficial for health maintenance because of functional ingredients, not food-enzyme, contained in them."

See: Shizuka HASE-TAMARU et al. (2018). “The in vitro and vivo evaluation of products so called ‘enzyme-foods’“

How to enjoy it?

Many people consume Koso for cleansing, but it can also substitute as a daily supplement.

Suggested Use Serving size 2 tablespoons (30ml / 1oz). Mix 2 tablespoons of Koso with 1/2 cup water or sparkling water. You may also try mixing with yogurt, milk, or alcohol for daily enjoyment.

Koso in the North America

There are not so many natural Koso available in the US and Canada. R’s KOSO is the only natural superfood supplement on the market that provides balanced nutrition, combining probiotics + prebiotics + postbiotics, which have proven to improve gut health and boost immunity. It's made from over 100 vegetables, fruits, and plants, including seaweeds and mushrooms, and undergoes about a 1-year fermentation process. Good to know : Gluten-free, NON-GMO, Dairy-free, VEGAN-friendly, Japan Made, 1-year fermentation, Contains Probiotics & Prebiotics. 70 years of experience to make Koso.

* The taste is like Sweet Japanese plum juice. We recommend mixing it with sparkling water. It's going to be Plum Flavor Prebiotic Soda.


Enhance gut health - our century-old traditional Japanese fermentation process provides a natural, plant-based, probiotic to support digestive health, skin radiance and, immune system.

Feeds your microbiome - rich in prebiotics and dietary fiber to feed the beneficial bacteria that reside in your gut and promote a healthy gut.

Better digestion - rich in probiotics and prebiotics to help you absorb more nutrients from the ingredients in the formula as well as the other foods you eat.

Healthy weight - Studies show taking prebiotic fiber caused positive changes in the gut microbiome, including increased levels of beneficial bacteria that are associated with a decrease in fat mass.

Antioxidant-rich - contain abundant functional ingredients, i.e., polyphenols, vitamin A, E, C. It gives your body a powerful shot of helping you neutralize toxins and promote healthy, clear skin, anti-aging.

Boost Immune system - our fermented superfood supplement made from 100+ vegetables and fruits, provides balanced nutrition, combining probiotics and prebiotics. The gut actually has about 70 percent of the body's immune cells. Taking balanced food is one of the big ideas to keep a healthy gut and boost immunity.


Serving size:2 tablespoons (30ml / 1oz) of R's KOSO mix with 1/2 cup water or sparkling water. 1 serving is calculated for Cleansing. It can be used 1/2 serving for daily enjoyment.

Storage:Refrigerate after opening and use within 4 weeks.

Methods:Try Koso Cleanse. 1 bottles is good for the following.

Methods Good For Suggested Use Recommended Duration

Breakfast Cleanse (every day)

2 weeks

1 serving

12 weeks

Breakfast Cleanse (4 Days/w)

4 weeks

1 serving

12 weeks

1-Day Cleanse

3-4 weeks

3-5 servings

12 weeks

3-Day Cleanse

1 program

3-5 servings

Every 2 months

Daily Enjoyment

2-4 weeks

1/2-1 servings

Every day (at least 12 weeks)


- 100+ INGREDIENTS - Vegetables, Fruits, Seaweeds, Mushrooms -

Leafy vegetables mix (cabbage, napa cabbage, lettuce, asparagus, broccoli, canola flower, celery, cauliflower, japanese mustard spinach, spinach, bok choy, taro stem, crown daisy, chisha lettuce, parsley, sprouts, perilla), Fruit vegetables mix (cucumber, wax gourd, tomato, eggplant, squash, bitter gourd, watermelon, corn, okra, bell pepper), Root vegetables mix (daikon, turnip, ginger, udo, yamato yam, nagaimo, potato, yam, japanese yam, sweet potato, carrot, lotus root, taro, burdock, lily bulb), Fruits mix (apple, quince, loquat, japanese plum, strawberry, chocolate vine, kumquat, apricot, sudachi, fig, mandarin orange, iyokan, kiwifruit, persimmon, peach, cherry, melon, grape, plum, pear), Brown sugar, Crude sugar, Malt sugar, Galacto-Oligosaccharide, Beet sugar, Starch, Japanese plum extract, Beans mix (kidney bean,
snow peas, fava beans, soybeans, black soybeans, red beans), Mushrooms mix (shiitake, shimeji, eryngii, wood ear, maitake, crimini, enokitake), Cereals mix (black rice, brown rice, red rice, sticky millet, barnyard millet), Seaweeds mix (kelp, wakame, sea lettuce, hijiki, nori, mozuku, tengusa), Herbs mix (plantago, dandelion, kumazasa, clover, aucuba, chickweed, saxifraga stolonifera, agrimonia pilosa, achyranthes bidentate, horsetail, japanese knotweed, water dropwort, mugwort, persimmon leaf, pine needles, cedar leaf, hiba, goji leaf, mulberry
leaf), Koji, Yeast, Lactic acid bacteria.

- 1-YEAR FERMENTATION - Prebiotics and Probiotics -

A century-old traditional drink, Koso has good bacteria which are Lactobacillus brevis, Lactobacillus plantarum, Lactobacillus casei, Lactococcus lactis. And galactooligosaccharide and dietary fiber are included as prebiotics. Dandelion Greens, Asparagus, apples, Burdock, Seaweeds act as prebiotics ingredients.


What does R's KOSO taste like?
R's KOSO is a Japanese plum flavored drink.

Is R's KOSO taste vegan?
Yes. R's KOSO taste does not contain animal-derived ingredients and the drink is plant-based.

How long has it been fermented?
R’s KOSO is fermented for about 1 year.

What’s the best way to take R's KOSO?
You can mix 2 tablespoons of R's KOSO with ½ cup of filtered or sparkling water. It's also good to take with yogurt, alcohol.

Is there an optimal time of day to take R's KOSO?
No, it can be taken at any time of the day that suits you. Especially we recommend you drink after you eat/drink too much. It is helpful to digest. Actually many Japanese women take it after dinner or replace the meal.

How does it compare to the Kombucha and other drinks?
R's KOSO is the only 100% plant-based supplement which has probiotics, prebiotics, acetic acid, Phenolics, vegetable, and fruits nutrients, Vitamins (A, B1, B2, B6, C, D, E, and K), Mineral (calcium, phosphorus, potassium, sodium, chloride, magnesium, iodine, iron, zinc, copper, manganese, iodine), 17+ Amino Acids, Short-chain fatty acid.

How different between Juice cleanse and Koso Cleanse?
R’s Koso’s Main feature is the benefit of Gut health. Compared to Juice cleanse, Koso Cleanse has probiotics and prebiotics that have positive impacts on your gut. Some research reveals that the gut is connected to the brain and skin.

Is R's KOSO safe to use when pregnant and when breastfeeding?
Yes, it's all natural plant-based food so you can take it.

Can I take it with other supplements?
Yes, R's KOSO can be taken with every other supplement because it's food.

Does it contain preservatives?
No, it is not contained it. The fermentation process made its shelf life longer.

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