Green tea is one of the most commonly consumed teas in the world.
Green tea extract is its concentrated form, with just one capsule containing the same amount of active ingredients as an average cup of green tea.
Like green tea, green tea extract is a great source of antioxidants. These have been credited with a range of health benefits — from promoting heart, liver, and brain health to improving your skin and even reducing the risk of cancer (1).
What’s more, many studies have looked at the ability of green tea extract to aid weight loss. In fact, many weight loss products list it as a key ingredient.
Despite these benefits, it’s important to know that green tea extract can also be toxic when taken in excess, so always talk with a health professional if you’re interested in taking these supplements.
This article explores 10 science-based benefits of green tea extract.
The health benefits of green tea extract are mostly due to its high antioxidant content.
Antioxidants can help reduce oxidative stress in your body by protecting against cell damage caused by molecules called free radicals. This cell damage is associated with aging and several diseases (2).
Polyphenol antioxidants called catechins make up the majority of green tea extract’s antioxidant content. Among the catechins in green tea, epigallocatechin gallate (EGCG) is the most researched and thought to provide the most health benefits.
Studies have shown that green tea extract increases your body’s antioxidant capacity (the activity of your body’s own antioxidant enzymes) and protects against oxidative stress. This, in turn, may prevent associated health concerns (3, 4, 5).
For example, in one 2012 study, 35 people with obesity took 870 milligrams (mg) of green tea extract for 8 weeks. Their blood antioxidant capacity increased from 1.2 to 2.5 micromoles per liter (μmol/L), on average (4).
It should be noted that the participants in this small study were taking green tea extract in an amount considered to be in the toxic range. Because of this, it’s unclear whether green tea extract would have the same effect if taken in smaller, safer doses.
SummaryGreen tea extract is rich in antioxidants called catechins, which have been shown to increase antioxidant capacity and protect against oxidative stress.
Oxidative stress increases fat buildup in your blood, which promotes inflammation in your arteries and leads to high blood pressure (6, 7).
The antioxidants in green tea extract can decrease inflammation and help reduce blood pressure. They can also inhibit fat absorption in cells, helping reduce blood fat levels (8, 9, 10, 11).
In one 2012 study, 56 people with obesity and high blood pressure took 379 mg of green tea extract daily for 3 months. They showed a significant decrease in blood pressure, compared with the placebo group (8).
Additionally, they experienced significant reductions in blood fat levels, including lower triglycerides and both total and LDL (bad) cholesterol (8).
An older study involving 33 people between ages 21 and 71 years old with no lipid imbalances found that taking 250 mg of green tea extract daily for 8 weeks reduced total cholesterol by 3.9% and LDL (bad) cholesterol by 4.5% (9).
Given that high blood pressure and high blood fat levels are risk factors of heart disease, regulating them can help promote heart health.
SummaryThe catechins in green tea may help reduce blood pressure and improve blood fat levels, which promotes heart health.
The antioxidants in green tea extract, especially EGCG, have been shown to protect brain cells from oxidative stress (12).
This protection can help reduce brain damage that could lead to mental decline and brain diseases like Parkinson’s, Alzheimer’s, and dementia (12, 13, 14).
Green tea extract can also decrease the action of heavy metals like iron and copper, both of which can damage brain cells (15, 16).
It’s been shown to help memory as well, by enhancing the connection between different parts of your brain.
In a 2014 study, 12 people drank a soft drink containing either 27.5 grams of green tea extract or a placebo. Then, while the participants worked on memory tests, brain images were obtained to assess brain function.
The green tea extract group showed an increase in brain function and improved task performance, compared with the placebo group (17).
SummaryGreen tea extract has been shown to have a positive effect on brain health and memory, and it may help protect against brain diseases.
Green tea extract is rich in catechins, and it contains a decent amount of caffeine. Interestingly, it seems that this combination of ingredients is responsible for green tea extract’s modest weight loss properties (18, 19, 20, 21).
Both catechins and caffeine have been shown to assist in weight loss by regulating the hormones that can enhance thermogenesis (19, 22, 23). Thermogenesis is the process by which your body burns calories to digest food and produce heat.
Green tea has been shown to boost this process by making your body more effective at burning calories, which can lead to weight loss (23, 24, 25).
In one older study, 14 people took a capsule containing a mixture of caffeine, EGCG from green tea, and guarana extract before each meal. It then examined the effect on calorie burning and found that the participants burned 179 more calories, on average, in the following 24 hours (19).
However, results are mixed.
In another well-designed study, 60 Caucasian adults took 560 mg of green tea extract along with between 280 and 450 mg of caffeine or a placebo daily for 12 weeks. This study found no significant effect on resting energy expenditure or body composition (26).
And since caffeine is known to stimulate energy expenditure, the modest weight loss effects of green tea extract may be due — at least in part — to the caffeine itself (27).
In fact, one study determined that green tea catechins don’t show any significant effect on energy expenditure when tested against caffeine alone (18).
Plus, the amount of caffeine you typically consume may affect your body’s response to green tea extract.
Those who regularly consume high amounts of caffeine (greater than 300 mg per day, or about 3 cups of coffee) may not experience as great an effect from green tea extract (20).
In one 12-week study, 115 women with central obesity (higher concentration of fat in the abdominal area) took 856.8 mg of green tea extract or placebo daily. Those taking the green tea extract experienced significant weight loss, along with decreases in BMI, waist circumference, and cholesterol levels, compared with participants who were given a placebo (28).
It should be noted that the dosage of green tea extract used in this study is in the toxic range for daily catechin intake. People taking high doses of green tea catechins should monitor their liver enzymes to avoid liver damage or acute liver failure (29, 30).
While a cup of green tea contains 50–100 mg green tea catechins and 30–40 mg of caffeine, studies of green tea extract often contain 375 mg or more of green tea catechins and up to 600 mg of caffeine.
Those with sensitivity to caffeine or cardiovascular issues should consider this before taking green tea extract for weight loss. It’s always good to speak with a healthcare professional so they can help you decide whether green tea extract is right for you.
SummaryGreen tea extract may aid weight loss by increasing the number of calories your body burns through a process called thermogenesis. However, the effect is modest, and it’s unclear whether green tea catechins or caffeine are responsible. High doses of green tea extract are toxic and may lead to serious liver damage.
The catechins in green tea extract may also help reduce inflammation caused by some liver diseases, such as nonalcoholic fatty liver disease (NAFLD) (31, 32).
One study gave 80 participants (ages 20–50 years) with NAFLD either 500 mg of green tea extract or a placebo daily for 90 days (31).
The group who received green tea extract showed significant reductions in liver enzyme levels, which is an indication of improved liver health (32).
Similarly, 17 patients with NAFLD took 700 mL of green tea, which contained at least 1 gram of catechins, daily for 12 weeks. They had significant decreases in liver fat content, inflammation, and oxidative stress (32).
However, as mentioned above, it’s important to have your liver functions tested regularly because excessive amounts of green tea catechins have been shown to be harmful to the liver (30). Talk with a healthcare professional to determine the right dosage for you.
SummaryGreen tea extract seems to help improve liver function by decreasing inflammation and oxidative stress.
The maintenance of your body’s tissues and organs is characterized by cell death and regrowth. Specialized cells known as stem cells produce new cells to replace those that die. This process keeps cells active and healthy.
When this balance is disrupted, cancer can occur. This is when your body starts producing dysfunctional cells, and cells don’t die when they should.
The antioxidants in green tea extract, especially EGCG, seem to have favorable effects on the balance of cell production and death (33, 34, 35, 36).
One small older study explored the effects of taking 600 mg of green tea catechins per day for a year on men at risk of developing prostate cancer.
It found that the likelihood of developing cancer was 3% for those receiving green tea compared with 30% for the control group (37).
SummaryGreen tea extract has been shown to help maintain cell health. It may even help prevent some types of cancer, though more research is needed.
Whether taken as a supplement or applied to the skin, green tea extract has been shown to improve skin health (38).
A large review demonstrated that when applied to the skin, green tea extract can help treat a variety of skin concerns, such as dermatitis, rosacea, and warts. As a supplement, it has been shown to help with skin aging and acne (38, 39, 40).
For example, a small study showed that consuming 1,500 mg of green tea extract daily for 4 weeks resulted in significant reductions in red skin bumps caused by acne (40).
Moreover, both supplements and the topical application of green tea extract seem to help prevent skin conditions like loss of skin elasticity, inflammation, premature aging, and cancer caused by exposure to UV rays (39, 41).
A study involving 10 people revealed that applying a cream containing green tea extract to the skin for 60 days resulted in improved skin elasticity (42).
Additionally, a study showed that applying green tea extract to the skin reduced skin damage caused by sun exposure (39).
Interestingly enough, adding green tea extract to cosmetic products has been shown to benefit the skin by providing a moisturizing effect (43).
SummaryGreen tea extract has been shown to help prevent and treat several skin conditions.
Green tea extract seems to be helpful in exercise, whether it’s by improving exercise performance or enhancing recovery.
While exercise has many health benefits, it’s known to produce oxidative stress and damage cells in the body. Antioxidants, like green tea catechins, can reduce cellular damage and delay muscle fatigue (44, 45).
In fact, a study involving 35 male students showed that green tea extract combined with strength training for 4 weeks enhanced the body’s antioxidant protection (46).
Additionally, 16 sprinters who took green tea extract for 4 weeks demonstrated increased protection against oxidative stress produced by repeated sprint bouts (47).
Green tea extract also seems to benefit exercise performance.
One study found that 14 men who actively engaged in physical activity and consumed green tea extract for 4 weeks increased their running distance by 10.9% (49).
SummaryGreen tea extract increases antioxidant protection against oxidative damage caused by exercise. This translates to better exercise performance and recovery.
The catechins in green tea, especially EGCG, have been shown to enhance insulin sensitivity and regulate the production of blood sugar, both of which can lower blood sugar levels (49, 50).
A study gave 14 people with no underlying health conditions a sugary substance and either 1.5 grams of green tea or a placebo. The group that consumed green tea experienced better blood sugar tolerance after 30 minutes and continued to show better results compared with the placebo group (51).
An older study showed that green tea extract improved insulin sensitivity in healthy young men by 13% (52).
Keep in mind that these studies (51, 52) were very small and that the participants had no underlying health conditions. Many people with diabetes, on the other hand, take medications that affect their liver, and many have NAFLD, so they would need to monitor their liver enzymes.
If you have diabetes, it’s important that you speak with your doctor before taking these supplements.
An analysis of 17 studies concluded that green tea extract is useful in decreasing fasting blood sugar levels. It can also help lower the hemoglobin A1C value, which is an indicator of blood sugar levels over the past 2–3 months (53).
SummaryGreen tea extract has been shown to increase insulin sensitivity and blood sugar tolerance, all while decreasing hemoglobin A1C and blood sugar levels.
Green tea extract is available in liquid, powder, and capsule forms. A wide selection can be found on Amazon.
The liquid extract can be diluted in water, while the powder can be mixed into smoothies. However, it has a strong taste.
The recommended dosage of green tea extract is between 250–500 mg per day. This amount can be obtained from 3–5 cups of green tea, or about 1.2 liters.
But it’s important to know that not all green tea extract supplements are created equal. Some supplements contain only dry green tea leaves, while others contain isolated forms of one or more catechins.
Because supplements are not FDA regulated to ensure safety, purity, or verification of contents, you should only purchase supplements that have been analyzed by an independent lab to verify purity and content.
The catechin most closely linked to the health benefits of green tea extract is EGCG, so you’ll want to make sure that the supplement you are consuming contains it.
Finally, it’s best to take green tea extract with food. Both exceeding the recommended dose and taking it on an empty stomach may cause serious liver damage (30, 54).
SummaryGreen tea extract can be consumed in capsule, liquid, or powder form. The recommended dose is 250–500 mg, taken with food.
Thanks to its high antioxidant content, green tea extract has been shown to help improve health and body composition.
Many studies have shown that green tea extract can promote weight loss, blood sugar regulation, disease prevention, and exercise recovery.
It can also help keep your skin and liver healthy, reduce blood fat levels, regulate blood pressure, and improve brain health.
It can be consumed in capsule, liquid, or powder form. The recommended dose is 250–500 mg a day, and it’s best taken with food. Amounts above this may be toxic. Plus, people with diabetes or those taking certain medications should speak with a healthcare professional before taking any amount of green tea extract.
Whether you want to improve your general health or decrease your risk of disease, green tea extract is an easy way to add health-boosting antioxidants to your diet.