Drinking kombucha is all the rage in the health and wellness world, and scientific studies back up the buzz. Many studies show kombucha can have various beneficial effects on your health, including detoxifying the body, reducing inflammation, acting as an antioxidant, providing energy, and boosting the immune system (1). But what happens when your kombucha experience falls short of this hyped-up expectation? Although it’s celebrated as a healthy drink, kombucha tea does come with some potential side effects that you need to know about. Read on to discover more about the upsides and potential downsides of drinking kombucha.

What Is Kombucha?

First, let’s get on the same page about what kombucha is. The term “kombucha” comes from combining the Japanese words for seaweed (kombu) and tea (cha) (2). Kombucha, also known as kombucha tea or kombucha mushroom, is a fermented tea generally made from black tea or green tea combined with sugar, starter liquid, and SCOBY — a symbiotic culture of bacteria and yeast (3). The starter liquid is simply one cup of kombucha, preferably homemade, but it can be store-bought if necessary. (Homemade kombucha brews generally have a greater diversity of bacteria than commercial versions.) If you’re worried about the sugar content, don’t be. Two hundred grams of sugar (one cup) goes into a one-gallon batch of kombucha. Thanks to fermenting, the finished kombucha drink is not that high in sugar. The sugar serves as food for the SCOBY and gets turned into vitamins and minerals throughout the fermentation process (3).

Potential Health Benefits of Kombucha

Consuming kombucha tea is well-regarded in the health and wellness industry. According to science, the potential health benefits of kombucha are wide-ranging. Kombucha can potentially help (2):

• Improve digestion
• Relieve arthritis pain
• Promote bowel movements by acting as a laxative
• Prevent microbial infections
• Combat cancer by preventing cancer cells from growing
• Relieve hemorrhoids
• Lower bad cholesterol (LDL) and increase good cholesterol (HDL)
• Rid the body and blood of toxins
• Balance the gut microbiome by acting as a probiotic and increasing the number of good bacteria
• Improve the symptoms of menopause, specifically hot flashes

Is Kombucha Safe for Everyone?

While kombucha offers many potential health benefits, this fizzy drink isn’t for everyone. For example, pregnant women and children should probably avoid kombucha as it has trace amounts of alcohol, which results from the fermentation process. For this same reason, kombucha may not be the right drink for those struggling with an alcohol addiction or have struggled with one in the past. According to registered dietician Casey Seiden, “Pregnant women are advised not to consume any alcohol-containing beverages; however, given the minimal amount present, drinking kombucha is seen as a personal choice, with the guidance of your doctor, during pregnancy” (4). Drinking kombucha is also not recommended for anyone who has a weakened or low immune system, especially those with HIV or cancer. One scientific study found kombucha may contain a mold known as aspergillus, which can cause a potentially fatal fungal infection in those with HIV (5). If you have liver or kidney disease, you should also steer clear of kombucha tea. According to family nurse practitioner, Sherril Sego, “more than 20 cases of cutaneous anthrax, as well as liver damage and allergic reactions” have been reported in relation to kombucha consumption (6). However, it’s worth noting that other studies indicate kombucha has hepatoprotective properties, meaning it can protect the liver (7). These studies were on rodents, and it is not yet clear how these results apply to humans. Always consult your healthcare provider if you’re concerned about the safety of drinking kombucha and possible kombucha side effects. Furthermore, kombucha can exacerbate symptoms for those with irritable bowel syndrome (IBS), including cramping, constipation, and bloating. Kombucha contains caffeine, sugar, carbonation, FODMAP carbohydrates, and alcohol, all of which may trigger IBS symptoms (8).

5 Kombucha Side Effects

The effects of kombucha are not favorable for everyone — some people experience adverse effects when consuming this carbonated beverage. Kombucha side effects may include anything from gastrointestinal upset to headaches to more severe symptoms. The Centers for Disease Control and Prevention (CDC) recommends healthy individuals drink no more than four ounces of kombucha daily (9). Of course, people who are pregnant, breastfeeding, or have medical conditions should consult their doctor before drinking kombucha. If you drink kombucha, especially more than four ounces daily, watch out for these five kombucha side effects:

1. Gastrointestinal Upset

While small amounts of kombucha may exert a positive impact on the gut microbiome due to its role as a probiotic, more is not necessarily better (10). Kombucha is a carbonated beverage, and science shows that carbonation can introduce carbon dioxide to the GI tract, which can cause increased gas production and bloating (11). Kombucha also contains FODMAP carbohydrates — fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. A diet high in FODMAPs can cause bloating and excess gas, especially among those with IBS. Indeed, many people with IBS find a low-FODMAP diet helps reduce the severity of their symptoms (12).

2. Weight Gain

The store-bought version of kombucha can pack a pretty big punch when it comes to sugar content. Many commercial brews have a lot of added sugar. If you’re regularly consuming an excessive amount of added sugar, your health may suffer. Studies show added sugar can contribute to a range of chronic illnesses, from “obesity, cardiovascular disease, diabetes, and non-alcoholic fatty liver disease (NAFLD) to cognitive decline and even some cancers” (13). So, if you’re struggling with weight gain, start by examining your sugar intake, especially if you drink a lot of store-bought kombucha. If you’re shopping for kombucha, try to keep the sugar content to under four grams per serving. If you make a homemade brew, you can control precisely how much sugar goes into the mix, and choose to keep it low.

3. Too Much Caffeine

If you’re a heavy kombucha drinker, you may be consuming more caffeine than you realize. Caffeine levels vary depending on the brand and the kind of tea used to make the kombucha. However, a good rule of thumb is that your kombucha brew should have one-third the amount of caffeine as the tea you used to make it (14). While caffeine is considered safe for most people, scientific studies show that some people are overly sensitive to the effects of caffeine, and it could affect their “cardiovascular function, sleep, and substance use” (15). People considered particularly vulnerable to the effects of caffeine include “pregnant and lactating women, children and adolescents, young adults, and people with underlying heart or other health conditions, such as mental illness” (15). If you notice that you feel anxious, jittery, or have a headache after drinking a kombucha beverage, it may be time to lay off the caffeine.

4. Lactic Acidosis

Lactic acidosis refers to “a build-up of lactic acid in the bloodstream that can be life-threatening” (16). Registered dietician Wendy Bazilian says the risk of developing lactic acidosis from drinking kombucha is slim (16). However, there is scientific evidence of lactic acidosis occurring in a young man who was diagnosed with HIV. Although this is a rare case, it’s worth mentioning, especially if you drink kombucha and have underlying medical issues (17).

5. Lead Poisoning

There have also been reported cases of lead poisoning with kombucha consumption, especially in the case of homemade brews. For example, a married couple who had been drinking homemade kombucha brews for six months contracted lead poisoning. It turns out that the lead came from the ceramic pot they were using to brew their kombucha (18). Although the risk of lead poisoning remains low, it’s worth noting to understand the risks associated with kombucha consumption. If you choose to make kombucha at home, make sure you follow proper guidelines on fermentation and carefully consider the materials you’re using to avoid toxic heavy metals.

Kombucha Side Effects: The Key Takeaway

Kombucha is a fermented tea commonly made from green or black tea combined with sugar, starter liquid from your last batch, and a SCOBY. This fizzy drink has wide-ranging health benefits, including helping with digestion, relieving arthritis pain, balancing the gut microbiome, lowering cholesterol, and more. But it’s not without its risks. Drinking kombucha, especially in excessive amounts, may cause gastrointestinal upset and weight gain. It may have too much caffeine for those who are sensitive to the stimulant, and it has even been associated with lactic acidosis and lead poisoning. However, the chances of experiencing the latter two are slim. Before adding kombucha to your diet, seek medical advice. Work with your doctor to determine whether or not this drink is for you. Those who are pregnant, breastfeeding, have an underlying medical condition such as HIV, cancer, irritable bowel syndrome, or liver or kidney disease should not drink kombucha. It’s also not recommended for children, as there is a small amount of alcohol in kombucha from the fermentation process. Want the latest tips on digestive health and overall well-being? Sign up for our email list and receive exclusive health tips we don’t share with the public.