Kombucha Health Benefits and Risks

Medically Reviewed by Shruthi N on May 26, 2024
8 min read

Kombucha is a fizzy, fermented drink typically made with either green or black tea. Although it is sometimes referred to as kombucha mushroom tea, it is not made with fungi. The “mushroom” is something called a symbiotic colony of bacteria and yeast, or SCOBY. When added to sweet tea and fermented, it creates healthful bacteria and B vitamins.  For this reason, it has been labeled as a functional beverage, which is any nonalcoholic drink with ingredients added to create health benefits.

Although relatively new to the United States, kombucha has been around for more than 2,000 years. It was first brewed in China and then spread to Japan and Russia. It became popular in Europe in the early 20th century. Sales in the United States are on the rise because of its reputation as a health and energy drink.

There are many claims that kombucha helps relieve or prevent a variety of health issues — from obesity and cardiovascular disease to cancer and diabetes. Scientists continue to search for evidence to back up these claims and prove why some elements of the drink may be good for you.

What does kombucha taste like?

In its basic form, kombucha is described as having a slightly sweet and vinegary taste or tanginess. It is often flavored with fruit, honey, or sugar. Fermentation gives kombucha its fizz, which you may find refreshing.

The basic ingredients in kombucha are yeast, sugar, and tea. The mix is set aside for a week or more. During that time, bacteria and acids form in the drink, as well as a small amount of alcohol. (Alcohol levels are typically below 0.5%.) This process is known as fermentation, and it’s similar to how cabbage is preserved as sauerkraut or kimchi, or how milk is turned into yogurt.

Kombucha SCOBY

Kombucha requires bacteria and yeast to begin the chemical process of fermentation, which gives it flavor and nutrition. The mutually beneficial — or symbiotic — relationship is formed when yeast breaks down the sugar added to the tea, which, in turn, feeds the bacteria that creates acid in the form of vinegar. When the SCOBY is added to sweet tea, it forms a film or spongy, jelly-like substance on top. This is why it is often referred to as a mushroom, although it is not a fungus. You might also hear it called the kombucha mother.

How to make kombucha

You need a SCOBY to start your first batch of homemade kombucha. You can save the SCOBY and use it for future batches of kombucha. 

Basic kombucha recipe:

  • ¼ cup loose green or black tea in mesh bags or 4-8 tea bags
  • 1 gallon of filtered water
  • 1 cup cane sugar
  • 1-2 cups kombucha starter liquid (often comes with your SCOBY or can be purchased)
  • 1 SCOBY

Add black or green tea to boiling water. Stir in sugar. Remove tea leaves or tea bags after approximately 10 minutes. Allow tea to cool to room temperature before pouring it into a large glass or stainless steel container and adding the SCOBY. You may also add a little vinegar and other flavorings, such as fruit puree, spices, or herbs. Cover the jar opening with cheese cloth or a coffee filter and secure with a rubber band to prevent contamination. 

Allow to ferment at room temperature for 7-10 days. Keep at least 1-2 cups to use as starter liquid for your next batch, and then refrigerate the rest to stop fermentation. If fermentation continues beyond 10 days, your kombucha could turn to vinegar.

Note: To avoid contamination from mold or harmful bacteria that could cause illness, always wash your hands thoroughly and sterilize any container you use to brew or store kombucha.

Does kombucha have alcohol?

Because kombucha is fermented, it does contain a low level of alcohol. Alcohol levels are typically below 0.5%.

Does kombucha have caffeine? 

When kombucha is made with green, black, or other caffeinated tea, it will contain caffeine. But the caffeine levels is very low -- less than 15 milligrams per cup.  

For centuries, kombucha has been drunk for its health benefits. The fermented tea contains vitamins, trace minerals, and antioxidants -- compounds that can protect your cells from damage. It doesn’t contain fat or cholesterol and is low in sodium. It also contains probiotics, which are good bacteria that can improve gut health. That said, there is little scientific research to back up the many health claims manufacturers and avid kombucha fans make. 

Kombucha calories

An 8 ounce serving of unflavored kombucha has about 30 calories, 2-3 grams of sugar, and a small amount of caffeine. Adding flavorings or fruit to kombucha may boost the nutritional value, calories, and sugar content. 

Drinking kombucha may provide a variety of health benefits, from aiding in digestion to ridding your body of toxins and boosting energy levels. It’s also said to help your immune system, help you lose weight, ward off high blood pressure and heart disease, and prevent cancer. But there’s not a lot of evidence to support these claims.

Kombucha and digestion

Fermented products in general are good for the microbiome and gut health. Fermentation makes probiotics, which help with constipation, diarrhea, and irritable bowel syndrome (IBS). But there's not enough research to show how these probiotics work. Experts say it's better to get your probiotics from a plant-based diet until we know more. 

Kombucha and your immune system

Since kombucha is made from either black or green tea, you get the benefit of tea’s natural antioxidant properties. Antioxidants help protect cells against damage. The process of fermenting the tea may increase these immune boosters. Gut health has been linked with the immune system, so probiotics that improve your gut health may also help strengthen your immune system. 

Does kombucha help you lose weight?

A recent study found that drinking kombucha may help lower triglyceride levels — in worms. The study found that drinking kombucha may create a metabolic change in the stomach that imitates fasting. Researchers also noted a reduction of fat accumulation, specifically triglycerides -- the fat that’s stored in the body when you eat more calories than you burn. More research is needed to determine if kombucha could have the same effect in humans.

Kombucha and heart health

Research indicates a relationship between gut health and heart health. Other studies in animals show that the drink lowers cholesterol. But research hasn’t shown that it has the same effects in people.

Kombucha and blood sugar

In a recent study, kombucha helped lower blood sugar levels in people with diabetes. On average, their fasting glucose levels decreased from high to healthy levels. Scientists don’t understand exactly why kombucha (which contains sugar) may be effective in lowering blood sugar levels, and more research is needed.

Kombucha and detox

The enzymes and acids produced by kombucha’s fermentation process may help remove toxins from the liver.

Kombucha and antioxidants

When kombucha is made from black tea or green tea, you get its benefits, too. This includes bioactive antioxidant compounds contained in these teas, such as polyphenols, that act as antioxidants. The process of fermentation has also been shown to increase antioxidants.

Making kombucha involves letting bacteria grow in a liquid you’re going to drink. These bacteria are considered healthy, but if it’s not prepared properly, it can grow harmful bacteria or mold. If you’re making it at home, experts recommend using glass, stainless steel, or plastic containers. Keep everything sanitary, including the equipment and your hands.

Since the mid-1990s, several cases of illness and at least one death have been reported in people who drank kombucha. Ailments included liver problems, lactic acidosis (a buildup of lactic acid in the body), allergic reactions, and nausea.

For this reason, the CDC recommends drinking only 4 ounces of kombucha daily. Overconsumption can lead to side effects, including headache, nausea, and upset stomach.  

Is kombucha safe?

When properly prepared and drank in moderation, kombucha is generally considered safe. 

Is kombucha safe during pregnancy?

If you’re pregnant, experts advise against drinking homemade or store-bought kombucha. There are two primary reasons: alcohol and caffeine. Because kombucha may contain even a low level of alcohol, it’s considered a risk to pregnant women. Likewise, the caffeine levels in kombucha may not be ideal for moms-to-be. There is also the possibility of bacterial contamination in kombucha, especially if made at home.

Is kombucha safe for kids?

Kombucha is not recommended for young children. Older children may enjoy kombucha, but because it contains caffeine and small amounts of alcohol, experts recommend limiting your child’s daily kombucha consumption.

Can you drink kombucha every day?

If you are pregnant or have a weakened immune system due to illness or treatment for an illness, you should avoid drinking kombucha. Otherwise, in moderation, you can drink kombucha daily. 

Today, commercially produced kombucha drinks can be purchased in most grocery and convenience stores and ordered online. If you want to make kombucha at home, kombucha kits, including the starter liquid and SCOBY, may be purchased online or specialty health food stores.

How long is kombucha good for after opening?

Store-bought kombucha may last in an airtight container in the refrigerator for up to a week after opening. After a week, your kombucha may lose its fizz and nutritional value. Kombucha gone bad will smell and taste vinegary and may look cloudy or slimy — and should be thrown away.

Kombucha is an ancient fermented tea that may have many health benefits, such as improving digestion, boosting the immune system, lowering cholesterol levels, and supporting cardiovascular health. Today kombucha is widely available in stores, and kombucha starter kits can be purchased to make at home. It’s important to follow safety guidelines when making kombucha at home to avoid contamination that could lead to potential food poisoning. 

What does drinking kombucha do for you?

Drinking kombucha may provide a variety of health benefits from aiding in digestion, to ridding your body of toxins and boosting energy levels. It’s also said to help your immune system, help you lose weight, ward off high blood pressure and heart disease, and prevent cancer. But there’s not a lot of evidence to support these claims.

Is kombucha a good probiotic?

Yes. Kombucha is made with a symbiotic colony of bacteria and yeasts (SCOBY) that includes lactic-acid bacteria, which can work as a probiotic.

When should I drink kombucha?

You can drink kombucha as a substitute for soft drinks. You drink kombucha for its potential health benefits, including to relieve stomach upset, to boost your immune system, or help lower high cholesterol levels.