Most consumers claim that kombucha benefits human health, being considered a remedy for almost any ailment or disease. Still, the reality is that many of these claims lack a scientific basis that can prove their benefits for humans.
Despite this, kombucha is still used by those who aspire to obtain these benefits. Some of these have been corroborated in laboratory tests or animal studies confirming improvements in health and the relief of some pathologies directed to digestive, immunosuppressive, and metabolic problems, among others.
What I do have to report before I start describing one by one the possible benefits of kombucha is that the scientific literature tested in humans is scarce and that the significant part of the benefits is inferred based on tests carried out on rodents, chickens or dogs, in addition to in vitro studies.
Kombucha has many antioxidants capable of eliminating a variety of free radicals such as DPPH, hydroxyl radicals, and superoxide radicals, contributing to reducing oxidative stress in the body and indirectly preventing the development of diseases associated with this process.
A test was carried out to verify this using several kombucha drinks prepared with different types of tea to demonstrate their ability to eliminate free radicals. All this was done following a 90-hour fermentation process.
In other tests, researchers used the same type of tea, but different starter cultures were inoculated in each kombucha. At the same time, it was left to ferment for ten days at 28ºC.
After all these tests, scientists confirmed its antioxidant capacity and how powerful it can be depending on the tea or ingredients used.
It was found that temperature, time, cultivation, and the tea used can generate different results regarding the concentration of antioxidants and other substances supporting their antioxidant effects, such as some organic acids and vitamin C.
Other substances that counteract oxidative stress
Kombucha has other components that intervene against oxidative stress, mainly vitamin C, glucuronic acid (GlcUA), and D-saccharic acid-1,4-lactone (DLS).
GlcUA prolongs the residence time of polyphenols in the body, achieving a more significant antioxidant effect, allowing them greater bioavailability and being a precursor for vitamin C production.
DLS has antioxidant and detoxifying properties produced by the lactic acid bacteria of the drink, reaching a peak of production on the 8th day of fermentation.
These substances were observed in studies on the composition of kombucha. Although their benefits for the human body are known, it cannot be assured that kombucha can generate these effects when consumed. Detailed studies on this are needed.   
Ability to detoxify the body
Kombucha can detoxify due to glucuronic acid, allowing you to remove pollutants, heavy metals, and toxins from the body. This occurs because GlcUA can bind to molecules to increase their excretion from the body through the kidneys or intestine.
It is even believed that it could prevent the development of certain diseases caused by the accumulation of toxins, such as gout, rheumatism, arthritis, kidney stones, etc. Even so, there is debate about the presence of GlcUA in kombucha and its ability to bind to toxins after consumption of the drink. (See our article on kombucha and gout)
Although scientists confirmed its ability to improve the detoxification process, it is still unknown how it is and if it is actually the GlcUA that participates or some other derivative, precursor, or similar substance to it.
There are no conclusive studies on this, but the more research is done, it will be possible to discern that it exerts these effects and probably verify if they can occur in humans. 
Possible anti-cancer effect
Most of these arguments about its anti-cancer benefits are just claims by consumers who believe they have found an effective therapy to alleviate the disease because they perceive an improvement in symptoms.
The research was conducted to verify these possible effects using laboratory tests and epidemiological studies. 
Studies where scientists showed anti-cancer properties
A population study in Russia in 1951 investigated the antiproliferative activity of kombucha prepared with black or winter savory tea. It was used in cells of cervical carcinoma, colon adenocarcinoma, and breast adenocarcinoma, where the scientist verified a decrease in the reproduction of cancer cells.
Another study observed a decrease in the survival of cancer cells in prostate cancer, demonstrating the possible potential of kombucha to inhibit angiogenesis during the development of cancerous tissue, impairing its growth due to lack of irrigation (nutrients). 
What can we think of this?
Despite these findings, it cannot be claimed that this also occurs in the human body. Many researchers consider that tea polyphenols and their breakdown products may manifest antiproliferative, antimutagenic, and antimetastatic effects and induce cancer cell death. Still, it is only considered as a possibility.
These studies from Russian organizations found a relationship between kombucha consumption, cancer resistance, and improved immune systems. The problem is that these data from more than a decade ago are not confirmatory about the effects of kombucha on cancer. 
Kombucha produces natural antimicrobial compounds capable of counteracting pathogens, mainly Gram-positive and Gram-negative bacteria, which help prolong the drink’s shelf life and possibly generate a protective effect on the body.
Its content of organic acids, catechins, and specific proteins that favor this antimicrobial activity raises the possibility that kombucha helps counteract some diseases caused by bacteria.
Several studies have attempted to test these effects. In one, regular kombucha and kombucha prepared with different medicinal plants were used. Then, pathogens were grown in plates, and some kombucha was added while the whole process was monitored.
Broad spectrum antimicrobial
In some studies, it was observed that traditional kombucha has fairly broad antimicrobial activity against pathogens. These effects can be enhanced by making an infusion with herbs, even being able to counteract several species of candida.
It was demonstrated through thermal tests that the antimicrobial effects of kombucha are not only due to the organic acids present in the drink but also enzymes, proteins, antibiotic substances, and specific fermentation metabolites that can negatively affect the development of a wide variety of microorganisms.
For this reason, kombucha is thought to help with gastrointestinal problems since, in theory, they fight the growth of pathogenic bacteria in our body and corrects imbalances. (See post about kombucha and yeast infections)
The only ones not significantly affected are the microorganisms in the drink that also stimulate the production of these antimicrobial compounds. Despite this, it cannot be considered therapy since there is no certainty that it generates these benefits in humans, but there is that possibility.
Health benefits through intestinal flora
Several in vitro studies have pointed out the possible health effects that kombucha can generate through the human intestinal flora. The drink could be able to correct intestinal dysbiosis with the contribution of beneficial microorganisms, managing to counteract various diseases related to this imbalance.
There are also several studies with animals, mainly rodents, investigating its effects against microbial sepsis and its relationship with the intestinal flora, proving that kombucha can generate an immunomodulatory impact with an anti-inflammatory reaction that counteracts systemic inflammation due to sepsis.
This has only been proven in rodents but does not rule out the possibility that it manifests similar benefits in the human organism, so it is encouraged to carry out the same analyses and follow-ups in humans to see if they can generate these effects.  
The probiotics in kombucha may benefit human health by supporting the growth of healthy bacteria in the colon and improving the absorption and digestion of food.
These effects relate to the mentioned benefits of kombucha, such as increasing HDL, lowering triglycerides, decreasing inflammation, and inhibiting the development of cancer and tumors.
Similarly, more human studies are needed to better describe the mechanism of kombucha microorganisms’ action on the human microbial flora and its components (or those produced by microorganisms at the colon level) on the organism as a whole. 
Prevention of liver damage
It has been shown in animal studies that kombucha can prevent liver toxicity caused by various contaminants and that depending on the dose or form of preparation, its level of protection may vary.
The relationship between the intestinal microbiome and the liver can
lead to the development of liver diseases as it is a route of exposure to pollutants from the colon. In addition, many of them can be produced by the microorganisms present there in cases of microbial dysbiosis.
Foods containing microorganisms with probiotic or prebiotic effects may help prevent liver diseases related to this dysbiosis. In addition, its content in DLS or gluconobacter species helps reduce liver damage caused by oxidative stress.  
There are no studies that confirm these effects in humans. So, for now, it is only proven in mice.
The hepatoprotective effect of kombucha also acts against hepatic steatosis of alcoholic and non-alcoholic origin (NAFLD). Although it was only demonstrated in mice, it is suggested by researchers that it could generate an effect among patients affected by NAFLD.
Thanks to glucuronic acid, it could act as an auxiliary of liver functions contributing to eliminating external pollutants and toxins produced within the body (bilirubin). With this, you can avoid its accumulation in the body which would lead to the development of diseases. 
By conducting studies in mice, it was observed that kombucha improved the antioxidant and detoxifying activity of the liver. It is not sure that it can do the same in humans, although that possibility is not ruled out. 
Improve overall metabolism
Kombucha provides many nutrients that can facilitate organic functions and metabolism.
The B vitamins are found in sufficient quantities to complement the diet and offer a high vitamin C content reaching 29 mg / L on the tenth day of fermentation.
In addition, the drink offers a wide variety of minerals that support the body’s normal functions, tissue maintenance, and growth. Also, its content of organic acids, besides its antimicrobial effect, can intervene in favor of sleep or have a detoxifying effect against some drugs.
These effects that could improve metabolism were only proven in vitro since no human studies were done that could confirm this fact. 
Prevent the development of diseases due to metabolic imbalances.
Kombucha could cleanse the body of some compounds byproducts from metabolism that, in high concentrations, can be harmful to health so that its components can collaborate in eliminating bilirubin and excess steroid hormones, among other substances.
Based on the above, you can prevent the development of specific pathologies associated with accumulating these substances in the body.
Also, the polyphenols of the drink that favor the elimination of free radicals could prevent the development of diseases associated with oxidative stress, such as CVD (cardiovascular disease), cancer, neurodegenerative disorders, etc.
Despite confirming the presence of many beneficial components for health in kombucha through laboratory analysis, it has not been proven that it can generate these effects in the human body, and it is unknown how they could act in the body, so more studies are required to verify this. 
Prevention of cardiovascular disease
In studies with mice, it was found that the decrease of some blood lipids (LDL, VDL) and plasma glucose and the increase of HDL (high-density lipoprotein) can prevent the development of cardiac disorders. 
In experiments with rabbits, positive effects were observed against some risk factors such as hypercholesterolemia, arteriosclerosis, and a decrease in blood sugar, in addition to lower cholesterol levels. 
Finally, it can generate a cardio-depressive effect in rabbits, rats, and rodents, which can decrease blood pressure. 
There are no studies that confirm its benefits to the human heart. Even with this, some scientists recommend it for people with cardiovascular diseases (also healthy), where daily consumption will give prophylactic effects. 
Is it possible to prevent myocardial infarction?
Kombucha may have a preventive effect on myocardial infarction, probably related to the benefits of the drink, such as lowering cholesterol, blood glucose, triglycerides, LDL, VLDL, and increased HDL.
Researchers conducted a study on mice and rabbits to learn about kombucha’s effects on specific causes of heart problems. They fed kombucha healthy rats and others with myocardial infarction (MI) during the experiment.
MI was induced with ISOPROTENEROL since the pathophysiological changes after its administration are comparable to those in humans. They also evaluated cardioprotective effects against various drugs using kombucha.
In conclusion, they prove that kombucha can protect cardiac cells against stress caused by ISO, where its antioxidants can stop the oxidative process caused by it and prevent damage to the cardiac cell membrane. It has not been tested in humans but is thought to have similar effects. 
Relief of inflammation and pain
Kombucha has components that generate an analgesic and anti-inflammatory effect, proven in studies with mice where different tests were carried out by administering three doses of kombucha in each.
These studies concluded that kombucha has analgesic effects similar to morphine (centrally acting analgesic) and a peripheral analgesic result. As for inflammation, an anti-inflammatory effect was likely due to its polyphenol content.
There is nothing to confirm this in humans. Still, its analgesic and anti-inflammatory capacity could be extrapolated to our body due to its components that manifest improvements in health.   
How the polyphenols act against inflammation and pain
Oxidative stress produces specific components that maintain and increase the sensation of pain in the tissues. In addition, this same pain can further enhance the oxidative process that causes it.
In this way, it enters a cycle that exceeds the internal capacity of the body to regulate the formation of these radicals through endogenous antioxidants.
Consuming foods rich in polyphenols can help reduce oxidative stress; therefore, kombucha can be effective, given its high antioxidant capacity. Anti-inflammatory and antioxidant effects were also observed
in pancreatic, hepatic, renal, and cardiac tissues in diabetic animals.
A kombucha prepared with Chinese herbs can intensify its effects against inflammation-related diseases. Using bark and oak leaves as a source of polyphenols complements the antioxidant effect of kombucha, being effective against inflammation in studies with human macrophage cells.  
It has only been confirmed through laboratory analysis; there are no studies done on humans.
Kombucha helps to lose weight.
Some studies point out the effects of consuming kombucha on weight loss, even evaluating the records of diseases associated with obesity and their relationship with alterations of the intestinal microbial flora where kombucha can intervene beneficially against them. 
Studies with male mice have proven the effects of kombucha in treating obesity and controlling weight gain, as the microbiological composition of the drink leads to the formation of compounds that intervene in some metabolic functions in favor of reducing obesity.
Vitamin C and B complex of kombucha decrease blood triglyceride levels showing antilipidemic effects. It was also observed that fermented foods such as kombucha with a microbial composition composed of lactobacilli tend to prevent weight gain thanks to the production of organic acids, mainly lactic acid. 
Gut flora and metabolism play an essential role in the development of obesity. A study with mice showed that maintaining microbial balance using kombucha can prevent weight gain and decrease hunger or appetite.  
Studies investigating their effects on humans are needed; there’s a good chance they will work.
Protect against diabetes
Studies with mice showed that it reduces hyperglycemia in type 2 diabetes through the intestinal flora, given its metabolic components and contribution of probiotics can generate an antihyperglycemic effect.
Because of this, some researchers believe that kombucha could serve as a possible treatment aimed at treating and preventing diabetes, and it is thought that it may work as part of the diet of diabetic patients. 
Even so, there are still no studies investigating and evaluating the antidiabetic activity of kombucha in humans, so you can only take these findings as a possibility.
On the other hand, polyphenols may generate an effect against diabetes, as oxygen free radicals negatively affect pancreatic cells, causing toxicity and decreasing the synthesis and release of insulin from them; therefore, kombucha polyphenols could be beneficial.
In other experiments, it was found that kombucha could inhibit the activity of pancreatic α-amylase, which plays a crucial role in the digestion of carbohydrates (sugars) at the intestinal level, increasing their absorption and, therefore, their blood levels.
The inhibition of this enzyme is used as a therapy for the control and prevention of postprandial hyperglycemia in human diabetic patients; therefore, it is considered that kombucha could work as a treatment.
Regulates blood cholesterol levels
Kombucha may reduce pancreatic lipase related to the digestion of fats to be absorbed later as free fatty acids, leading to decreased cholesterol and triglyceride levels in the blood, according to studies using kombucha in diabetic rats and in vitro.
It was confirmed that kombucha improves the lipid profiles (total cholesterol, triglycerides, LDL, HDL) of mice achieving weight loss; these effects can be enhanced if prepared with sea grape working to treat obesity and control blood lipid levels. 
Dyslipidemia in humans and animals causes oxidative stress that overwhelms the antioxidant defense system, affecting liver and kidney function in diabetic rats.
Improve hair health
Apparently, some components and microorganisms present in kombucha may be able to stimulate its growth, so the drink was applied topically on the scalp in mice to investigate its properties for hair growth.
As a result, a higher density and length of hair was observed in the mice, becoming less brittle and more resistant, demonstrating the ability of kombucha to stimulate hair growth.
Another test used kombucha with methylsulfonylmethane, which can also stimulate hair growth.
Both effects were synergistically enhanced, so their combination could work as an alternative and natural therapy to prevent hair loss, being more profitable and having fewer side effects than other hair remedies. (see the post about kombucha and hair loss)
There are no studies that prove this in human hair, but it is likely to improve the health and growth of this. 
Improve skin health
Kombucha can have an effect that improves skin health and helps in repairing wounds effectively. Its benefits were verified in aged mice, proving that the drink can correct skin abnormalities related to aging.
In one study, kombucha tea was used in old mice where a significant increase in collagen in the skin and an improvement of connective tissue abnormalities in the aging skin of mice was observed. It could be a cosmetic product in the future, but relevant human studies that can demonstrate this are required. 
Kombucha can also treat wounds, thanks to its antibiotic and detoxifying properties, but mainly due to its regenerative effects on damaged or aging skin and recovering radiance.
Tests were conducted on mice with lesions on their loins to check these effects. It was shown that kombucha could accelerate the healing of an open wound and, depending on the injury, stimulate hair growth again. I leave the article on the effect of kombucha on acne.
This has not been tested in humans, but there is a good chance it will generate these effects. 
Prevent neurodegenerative disorders
It is also considered that kombucha can prevent the development of neurodegenerative diseases because of its content of amino acids, methylxanthines, B vitamins, and ascorbic acid which are necessary to maintain the normal metabolism of the nervous system. 
Thanks to this, it could prevent the onset of headaches, anxiety, and epileptic seizures and control the development of neurological disorders such as Parkinson’s or Alzheimer’s.
This is only considered due to its composition and laboratory studies, it is possible that kombucha could be used in the future as a therapeutic strategy in humans, but more studies are needed to confirm this. 
Relieve arthritis symptoms
Several studies observed a relationship between the microbiome and rheumatoid arthritis, where the symptoms of the disease can be alleviated through the stability of the intestinal microbial flora.
It is believed that probiotics could intervene in the development of rheumatoid arthritis by decreasing the signs of inflammation in the body, but it has yet to be confirmed.
Also, it could be tricky if probiotics are given while medicating with arthritis medications. 
Even so, consuming foods containing beneficial microorganisms for the body, such as kombucha, could be helpful as a treatment. 
Although no human studies have been conducted to prove it, this possibility is validated after observing an improvement in affected mice.
Improvement of the immune system
In tests with mice, kombucha was used to verify its effects on the immune system. It was found that the drink can improve immunity, even surpassing the state of immunosuppression induced in some mice.
Due to this, an improvement in the weight and count of immune system cells such as white blood cells (lymphocytes), macrophages, and NK cells responsible for fighting some infectious agents that invade the body was observed, in addition to a possible immunomodulatory effect. 
Another study used mice infected with Salmonella Typhi that were fed black tea or turmeric kombucha. It was shown that the drink improved mice’s innate and adaptive immunity. Also, the kombucha prepared with turmeric was the one that manifested the most potent effect. 
It is not proven in humans, but it is possible to generate similar effects on the immune system; more studies are needed to confirm if this improvement can also occur.
Prevents kidney disease
Tests were conducted on male albino rats to verify the effects of kombucha on kidney disease. As a result, it was proven that kombucha could reverse the pathological changes brought on by oxidative stress in the kidneys. 
Kombucha can also facilitate the elimination of pollutants and toxins that can accumulate damaging kidney tissues, thanks to its acetic acid content that can combine these toxins to eliminate them from the body. It is believed that it may benefit patients suffering from kidney failure. 
Human trials are required to verify its therapeutic effects on renal failure in affected people, so it cannot be recommended as a treatment until this fact is confirmed.