Green tea extract

Concentrated green tea catechins in a capsule, taken most often for weight.

People take it for

Weight and body fat
Inflammation
Exercise and recovery
Cholesterol
Blood sugar

A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.

Compare green tea extract prices per dose

What is green tea extract?

Green tea extract is the leaf of Camellia sinensis concentrated into a powder and put into capsules. What supplements are built around is the catechins, a family of polyphenols found in the leaf, and above all the one called EGCG, which reviews describe as the most abundant of them. Labels usually carry a standardisation, such as 50 per cent EGCG or 98 per cent polyphenols, and some extracts are decaffeinated while others keep the caffeine that came with the leaf. It has been trialled a good deal: one review of body composition alone pooled fifty-nine randomised trials.

Why do people take green tea extract?

Weight and body fat

The thinking. Weight is what green tea extract is reached for more than anything else, and it is where most of the research has gone. The ideas being tested are that its catechins raise the energy the body burns at rest, and cut how much fat is taken up from a meal.

What research has found. The largest review pooled fifty-nine randomised trials in 3,802 people and found small average falls in body weight, body mass index and body fat percentage, though fat mass in kilograms did not move. Two individual trials, over twelve weeks and over a year, found no clear difference from a dummy capsule, and one measured fat absorption and resting energy burn directly without seeing a change. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.

Inflammation

The thinking. Green tea’s reputation is built on antioxidants, and plenty of people take the extract for nothing more specific than that: a sense of being run down, of aches that move about, of recovering slowly. The thinking is that its polyphenols settle the reactive chemistry in the body and quieten the signals tissue sends out when it is irritated.

What research has found. This is measured in blood tests rather than in how anyone feels. One trial put overweight middle-aged men through eight weeks of walking, jogging and circuits; the men who also took 500 mg of extract a day saw larger falls in two inflammation markers, interleukin-6 and C-reactive protein, than the men who trained without it. Few studies have measured this yet, so there is little to go on either way.

Exercise and recovery

The thinking. Hard training throws off reactive molecules and leaves muscle sore and stiff for a day or two afterwards. Some people take green tea extract around their sessions on the thinking that its polyphenols take the edge off that chemistry, so the next session comes round sooner.

What research has found. Three small trials, in untrained men, in sprinters and in men in regular high-intensity training, measured both blood chemistry and how people felt. In two, the blood’s antioxidant capacity rose and a marker of oxidative damage fell; in the third neither moved. What people would notice did not follow: soreness was rated no lower, sprint times did not change, and a marker of muscle damage came down in one trial but not another. The studies disagree, so this is unsettled: dose, duration and who took part all seem to shift the result.

Cholesterol

The thinking. Cholesterol and triglycerides are what people often go looking for a supplement about after a blood test. The thinking is the antioxidant idea applied to the fats circulating in the blood, and to how much fat the gut takes up from food.

What research has found. A review of seven randomised trials in adults with type 2 diabetes found lower triglycerides on average, most clearly in trials that ran beyond eight weeks; total cholesterol came down in the longer trials at lower doses. A crossover trial in 73 overweight women with raised LDL found LDL about 4.8 per cent lower on the extract, while total cholesterol, triglycerides and HDL were no different. Research here is still young: a few studies so far, mostly pointing the same way.

Blood sugar

The thinking. Green tea extract turns up in routines aimed at blood sugar, usually after a test has come back a little high. The thinking runs alongside the weight one: that if the body handles fat and energy a little differently, it may answer insulin a little better too.

What research has found. A review of seven randomised trials in 510 adults at raised risk of type 2 diabetes found no clear difference from a dummy capsule in fasting glucose, insulin, glycated haemoglobin or insulin resistance. A single three-month trial in 56 adults with obesity and high blood pressure did find fasting glucose, insulin and insulin resistance lower on 379 mg of extract a day. A fair body of trials has looked at this, and most point the same way.

What does green tea extract do in the body?

Green tea leaf is full of polyphenols called catechins, and the one supplements are standardised to, EGCG, is the most abundant of them. Reviews credit it with antioxidant and anti-inflammatory activity, and that is the thread running through almost all of the research: trials that measured the blood’s total antioxidant capacity generally saw it rise, and malondialdehyde, a marker of oxidative damage, generally fell.

Reviews also describe EGCG acting on bacteria and on the signalling that turns inflammation up and down. Two things complicate the picture for anyone reading the trials. Some of what green tea does may belong to its caffeine rather than its catechins, and researchers say they cannot always tell the two apart. EGCG is also absorbed and cleared unevenly, so a good deal of newer work goes into delivery systems and chemical tweaks that get more of it into the blood and keep it there longer.

What do people say about taking green tea extract?

These are anecdotes people have shared, not evidence.

No community discussions have been summarised for this page yet.

What forms of green tea extract are there?

Form	What’s different	Per serving, on products we list
Green tea extract (by EGCG)	Concentrated green tea leaf, sold by its EGCG or total polyphenol percentage, caffeinated or decaffeinated.	not in our price tables yet

What else is worth knowing about green tea extract?

Liver enzymes: in a one-year trial of 843 mg of EGCG a day, 6.7 per cent of the women taking it had a raised ALT reading, a liver enzyme measured in a blood test, against 0.7 per cent on a dummy capsule, and in 1.3 per cent the rise was recorded as a serious adverse event. A later analysis of the same trial found those rises clustered in women carrying one version of a gene that handles the compound.
In that same year-long trial, about three-quarters of both groups reported some unwanted effect and the overall rates were much the same. The extract group reported more nausea and more skin complaints, and less diarrhoea, than the group on the dummy capsule.
Labels count different things: some give the weight of the extract per serving, some the EGCG inside it, some the total polyphenols, and a serving may be more than one capsule. Trials have used anything from 379 mg of extract a day to 843 mg of EGCG.
Much of the long-term evidence comes from a single large trial in postmenopausal women, and the weight and blood-fat trials were mostly in adults who were overweight or already had raised blood sugar or cholesterol.

If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.

The research behind this page (13 studies)

How much does green tea extract cost?

That depends on the form and the pack, so we work out the price of the same dose of every green tea extract product we can find and rank them.

Compare green tea extract prices per dose