Amount of Evidence: Very High Potential Benefits: High Safety: High
TABLE OF CONTENTS
What is green tea?
Green tea is a type of tea that is made from Camellia sinensis leaves. This type contains more catechins (such as EGCG) and less caffeine than many other types of tea, such as black tea, which makes it more beneficial in some important ways. In this article, we will look at the main benefits and side effects of green tea, and how to drink it the right way.
Potential benefits
It is important to note that all of the potential benefits mentioned below are dose-dependent. In general, the more tea you drink, the more pronounced these effects will be. However, some of them do reach a plateau at a certain point. We will discuss how much tea to drink later in this article.
Major benefits
Reduced fatigue and sleepiness – Caffeine, the main stimulant in green tea, has a similar molecular structure to adenosine and because of that, it can enter and fill adenosine receptors. When adenosine molecules enter the receptors, they send a signal to the body that it is time to fall asleep, making you relaxed and sleepy. When caffeine fills the receptors instead of adenosine, adenosine molecules cannot enter the receptor for as long as the caffeine remains in the system, which delays the sleep-inducing effect of adenosine.
Increased power output – This benefit is also caused mainly by caffeine and applies to all forms of high-intensity exercise, including sprints and strength training.
Fat loss – Tea appears to be quite effective for fat loss because of the synergy between catechins and caffeine. Neither of those components is very effective on its own but the combination of these compounds is what makes green tea very useful if you wish to burn fat. It seems to be the case that caffeine can increase metabolic rate indirectly by increasing power output during exercise, which would make tea more effective for fat loss when you drink it before exercise. Also, this would mean that green tea is more beneficial for people who exercise than for those who do not, which does appear to be the case.
Improved heart health – Long-term consumption of green tea and other types of tea from the Camellia Sinensis plant has been associated with improved heart health and reduced risk for heart disease and other cardiovascular diseases.
Antioxidant effects – EGCG and other catechins in tea have been shown to notably decrease oxidation in the body. This effect may be the main reason why many types of tea have been shown to lower the risk of cancer.
Increased aerobic capacity – Tea significantly increases aerobic capacity. This effect has been studied primarily in runners but applies to all forms of endurance training (cardio). This benefit is mainly due to the stimulant effect of caffeine.
Improved cholesterol levels – Green tea polyphenols (such as EGCG) have been shown to both increase HDL cholesterol and lower LDL cholesterol. The decrease in LDL appears to be more notable than the increase in HDL. One study also found that green tea catechins reduce the oxidation of LDL to a small extent. Caffeine itself has no notable effect on cholesterol levels.
Up-regulation of dopamine – Caffeine in tea significantly increases the upregulation of some dopamine receptors. Because of this, it makes you able to experience more dopamine-related effects without significantly increasing dopamine levels in your system. Caffeine also increases dopamine levels to some extent but the increase is small.
Minor benefits
Improved cognition – Green tea appears to slightly improve cognition independent of caffeine’s effects. This benefit is most notable in people who have poorer cognition at baseline but also applies to cognitively sharp individuals to a smaller extent.
Improved skin quality – A high intake of green tea catechins leads to an improvement in skin quality. Specifically, these polyphenols can reduce acne.
Improved dental health – Green tea has been shown to have anti-microbial properties and can protect your gums from bacterial infections.
Reduced muscle soreness – This benefit has more to do with the catechins in tea than caffeine. The effect is most notable if you overtrain or if you are a beginner at resistance training.
Neuroprotective effects – Green tea has been shown to protect the neurons in the brain.
Increased adrenaline and noradrenaline – This effect is caused by caffeine but lowered to some extent by catechins in tea. Depending on how you look at it, this effect can either be viewed as a benefit or as a negative. The increase in those two neurotransmitters can be very useful if you want to increase alertness and exercise performance.
Increased longevity – Green tea usage has been associated with a 6% increase in longevity in mice. Unfortunately, there are not enough human studies yet to know what the effect of green tea is as far as slowing down aging.
Lowered blood pressure – This benefit of EGCG and other catechins in tea indicates that tea is a safer way to consume caffeine than coffee for those who have problems with blood pressure. However, this effect is relatively small since caffeine can raise blood pressure and negate this benefit to a certain extent.
Protection from DNA damage – Green tea has been shown to reduce DNA damage. This effect appears to be most notable in unhealthy individuals, such as diabetics.
Chelation of heavy metals – Tannins and caffeine in tea can bind heavy metals and help detoxify them.
Improved insulin sensitivity – Green tea has mixed effects on insulin sensitivity but in general, it usually leads to an increase. This effect is most notable in unhealthy people with insulin resistance. Green tea catechins have also been linked to a reduction in fasting blood glucose levels but not fasting insulin levels. While caffeine can worsen insulin sensitivity, this effect only occurs acutely when caffeine is combined with a meal rich in carbohydrates. Insulin sensitivity then quickly returns to normal and is not affected negatively in the long term.
Increased endurance – Rating of perceived exertion (RPE) decreases in most people when they drink tea before an exercise session. Caffeine has also been shown to increase training volume (the total work done during an exercise session) in both endurance and strength training.
Improved reaction time – While this benefit is small and the evidence is rather limited, caffeine in green tea has been shown to improve reaction time in certain situations.
Increased blood flow – Green tea causes a slight increase in blood flow. This effect applies to both the catechins in tea and caffeine. When taken together, the benefit is multiplied.
Increased subjective well-being – Numerous studies have shown that green tea and other sources of caffeine significantly improve mood and well-being in the short term. This effect appears to be even more notable in tea than in other sources of caffeine because of tea’s catechin content. The long-term effects on well-being have not yet been established and depend greatly on the individual. It appears that caffeinated beverages can both increase and decrease long-term well-being, depending on how one responds to caffeine, what time of day one consumes the beverages, etc.
Reduced iron absorption – The caffeine, tannins, and catechins in tea can lower iron absorption by up to 30%, depending on how close to your meals you drink tea. This can be seen as a benefit for those who have too much iron in their bloodstream, which is just as common (if not more common) as iron deficiency.
Increased thermogenesis – Green tea increases the body’s ability to generate heat from brown fat. This is the main effect responsible for fat loss.
Liver health – The evidence is somewhat weak in this regard. However, there is at least some amount of data that shows green tea may be beneficial for liver health in the long term.
Increased metabolic rate – While the catechins in tea have not been correlated with increased metabolism, green tea and other types of tea can speed up your metabolism. This mostly has to do with caffeine and its synergistic effects with catechins. It seems to be the case that caffeine in tea can increase metabolic rate indirectly by increasing power output during exercise. However, tea may slightly increase metabolism even in those who do not exercise.
VO2 max – Interestingly, green tea catechins have been shown to increase VO2 max levels to a small extent. This effect applies mainly to untrained people. Caffeine does not improve VO2 max in the short term. However, it may indirectly increase your VO2 max in the long term by increasing power output and making you more effective at aerobic and anaerobic exercise.
Unproven benefits
The effect of green tea on these parameters has either not been sufficiently researched or the science shows little to no efficacy in these areas.
Testosterone – Catechins in green tea have the potential to both increase and decrease testosterone, depending mainly on the dose but also some other factors. Usually, low amounts of green tea appear to slightly increase testosterone levels in most people while high amounts appear to decrease it, especially if your testosterone levels are already high. Also, there is a good amount of evidence on the relationship between caffeine and testosterone. A 12% increase in testosterone was noted in trained individuals who took 250 mg of caffeine before a training session. Although 12% sounds like a lot, this is a relatively small increase compared to many other supplements that have been shown to increase testosterone. Also, this benefit is dependent on physical activity and does not apply to individuals who do not exercise.
Heart rate – The catechins in tea can indirectly lower heart rate (by lowering blood pressure and helping you burn fat) but caffeine has been shown to slightly raise the heart rate. An increase is highly dose-dependent and has been noted especially in people who are very sensitive to caffeine. Even then, the effect of caffeine on heart rate is not significant in healthy people. So overall, green tea doesn’t have a notable impact on heart rate.
Memory – The evidence is highly mixed. From the studies we have so far, there seems to be a mild increase in spatial memory but a decrease in working memory associated with caffeine. The negative effect on working memory may be due to overstimulation and thus is not as likely to happen if you get your caffeine from tea (because of all the other chemicals in tea, such as l-theanine).
Appetite – There is little to no correlation between green tea and appetite for food.
Bone health – Green tea does not significantly influence bone mineral density.
CRP (C-reactive protein) – No strong connection between green tea and CRP has been observed.
Triglycerides – No significant influence on fasting or postprandial triglycerides has ever been noted.
Possible side effects
Most of these side effects are associated with caffeine and do not apply to decaffeinated tea. Also, these side effects are dose-dependent and the risk for them increases (most often linearly but sometimes exponentially) as the dose is increased. Some of the side effects are relevant only at very high doses.
Anxiety – This effect varies greatly from person to person. Your genes and your psychological state play a huge role in whether or not tea is likely to make you anxious.
Shaking – This is one of the effects of caffeine that seem to increase exponentially as you increase the dose. The shaking could in one way be viewed as a positive effect as it might be a form of somatic releasing. However, we do not know yet whether or not the shaking induced by caffeine can lead to improved psychological well-being in the long run. It may simply be an unpleasant sign of overstimulation.
Yellow teeth – Beverages that contain caffeine (such as tea, coffee, and energy drinks) can turn your teeth yellow if consumed regularly. Unfortunately, this effect seems to be more problematic in tea than in coffee.
Adrenal fatigue – Caffeine can cause adrenal fatigue and adrenal burnout if you regularly consume it to the point where you do not allow the body to rest enough and repair the adrenals. Adrenal fatigue can lead to a variety of health problems. This is perhaps the main reason to cycle caffeine and stop using it for a week or so every once in a while.
Worsened sleep quality – Caffeine in tea can make it harder to fall asleep and shorten the time you spend in deep sleep. This effect can occur even if you drink caffeinated tea earlier in the day, as the half-life is about 5 hours and can be as long as 9.5 hours in people who metabolize caffeine slowly.
Disruption of circadian rhythms – This can happen for two reasons: either because of the effect caffeine has on your sleep or because of disrupting the natural morning cortisol rise when you drink caffeinated tea in the first 90 minutes after you wake up. We will look into this effect more deeply later in the article.
Dependence – When you consume caffeine regularly, more adenosine receptors are formed, making you dependent on caffeine. You will then need more and more tea or other caffeine sources to get the same effect.
Caffeine withdrawal – When you stop drinking green tea or other sources of caffeine, the adenosine receptors will start getting broken down, which leads to the symptoms of withdrawal, such as headaches, fatigue, and getting angry and annoyed easily.
Decreased absorption of certain minerals – Specifically, the catechins, tannins, and caffeine worsen the absorption of iron and zinc, which may and may not be a concern to you. Since a somewhat high percentage of people are deficient in those two minerals, you may want to avoid caffeine close to your meals to minimize this effect, especially if you are experiencing signs of deficiency in these two minerals. On the other hand, this effect can also be viewed as a benefit since many people have too much iron in their bloodstream, which can lead to iron toxicity and faster aging.
Increased blood pressure – While the rise in blood pressure doesn’t apply to tea nearly as much as it does to other sources of caffeine (if at all – there is a good amount of evidence to support that tea actually decreases blood pressure), people with already high blood pressure should be aware of this potential side effect and probably limit their caffeine intake.
Increased cortisol – This effect mainly applies to other sources of caffeine but tea can also increase cortisol levels to some extent.
Nausea – This side effect usually only happens if you drink a very strong cup of tea and is caused mainly by the catechins in tea. Nausea caused by tea is not linked to stomach damage and is by no means dangerous.
Diarrhea – This is the most common short-term side effect as it can happen even at low doses.
Esophageal cancer – While the catechins in tea can protect you against cancer, tea can also increase your chance of esophageal cancer if you drink it the wrong way. This possible side effect is not related to the tea itself but to hot water. If you drink the tea while it is too hot (60°C / 140°F or more), it can damage your esophagus and increase your risk for esophageal cancer.
Fillers in tea – This is not a problem connected to the tea itself but some brands sell tea that contains sweeteners and other potentially harmful chemicals. Also, it is important to note that tea with sugar or milk in it can easily cause more harm than good. Many of the benefits above do not apply if you add these to your cup of tea.
Who should not drink green tea?
You should probably avoid green tea if you:
have a zinc or iron deficiency (caffeine, tannins, and other compounds in tea can reduce the bioavailability of these minerals)
have difficulty falling asleep and staying asleep in the evening
are pregnant
want to avoid the teeth-yellowing effect
feel anxious or jittery after drinking tea
Who will benefit the most?
You should definitely consider drinking green tea if you:
want to lose fat
are a serious athlete trying to maximize exercise performance
need to increase energy and alertness on certain occasions
have too much iron in your system
How much green tea should you drink?
People often give very simplified answers, like 3-5 cups a day. However, anywhere from 0-15 cups is a good amount to consider, depending on what you want to get out of tea.
Even one cup can provide notable benefits related to the catechins in tea. However, the benefits do not seem to plateau even after 5 cups a day.
To find out how much green tea you want to drink, you have to first figure out what the best dose of caffeine is for you because caffeine is the primary stimulant compound in tea responsible for most of the short-term (and possibly also long-term) effects of tea.
All of the numbers below apply to caffeine. Since green tea’s content is typically around 20 mg, you can divide the doses below by 20.
How much caffeine you should ingest depends on many factors, such as your weight, how sensitive you are to caffeine, and how fast you metabolize the compound.
You should also take into consideration your personal goals and what you want to get from the stimulant. For example, if you wish to maximize exercise performance, that will require a different approach to dosing than if you simply want to increase alertness and reduce fatigue.
Most scientific studies on caffeine use doses of 4-6 mg/kg. However, this dose seems to be a little too high unless you are a serious athlete and want to maximize power output during exercise.
If you are an average individual with an average tolerance, a dose of 100-200 mg a day appears to be ideal for most people. This dose will still allow you to be more energetic and productive but it will not impact your sleep negatively if you take it (or drink it) early in the day.
If you have been regularly taking higher doses of caffeine, you may be able to consume more than 200 mg without the negative impact on your sleep.
The best way to determine whether or not you can handle higher doses is by listening to your body. Specifically, how easy or hard it is for you to fall asleep is a good indicator of whether or not you should cut back on caffeine.
If you experience more anxiety after taking the stimulant, that is a sign you may want to cut back on it and lower your dose. So caffeine dosing depends heavily on an individual and varies greatly from person to person. To know the optimal dose you should take, you will need to experiment a bit.
It is important to note that you do develop tolerance to caffeine over time and the higher the dose you are taking, the sooner the tolerance will develop and the more intense it will be. Fortunately, you can get rid of the tolerance by going through a caffeine cycle at least once in a while.
Probably the best caffeine cycling protocol to reset your tolerance for the compound is going cold turkey for a week every 3 months. While the week without the stimulant will probably be unpleasant (most people experience headaches, low energy, and get agitated very easily), the pain is worth going through if you wish to maximize the benefits of caffeine.
If you have been consuming caffeine every day or nearly every day for many years, you will probably need more time than a week to get back to baseline and become fully sensitive to the stimulant. In the most extreme cases, this takes up to 3 months. However, 1-2 weeks should lead to most of the restorative effects.
Also, if you wish to get through the withdrawal phase faster, one very effective way to do it is sleep banking, where you try to sleep as much as possible (even if it’s 12-16 hours a day) to allow your body to get back to baseline faster.
Fortunately, there is no way you would drink so much tea that it would lead to toxicity. Doses of 20-40 mg/kg of caffeine have been shown to be toxic. Even 10 mg/kg is too much and this amount would almost certainly cause more harm than good for the vast majority of people. But to achieve this amount, you would have to drink at least a couple dozen cups of tea.
So to give a general recommendation, 5 cups of green tea should provide most of the benefits without meaningful side effects. But again, this recommendation is extremely simplified and does not apply to everybody.
Best time to drink green tea
The best time to drink caffeinated green tea is around 90 minutes after you wake up.
This is because, in the early morning, there is a natural increase in cortisol responsible for waking you up and getting you ready for the day. By drinking coffee, tea, or ingesting caffeine from other sources right after you wake up, you would interrupt this natural increase in cortisol and your body would not be producing as much of it in the following days. This would lead to increased production of cortisol at the wrong times of the day, such as in the evening. After the morning cortisol increase that typically lasts 90 minutes after waking up, you want to drink the tea as soon as possible so that most of it leaves your system before it’s time to go to bed.
The half-life of caffeine is on average around 5 hours but this depends heavily on your genes. Some people metabolize the stimulant very fast but some are so-called slow caffeine metabolizers. The half-life can therefore last anywhere from 1.5 to 9.5 hours. If you have your genetic results available, CYP1A2 is the main gene that regulates caffeine metabolism and how fast your body gets rid of the compound.
As a general rule of thumb, drinking coffee or strong tea after 2 pm is not a good idea unless you know you are a fast metabolizer. But obviously, this advice is very simplified and doesn’t take into consideration all the variables.
Again, the best way to determine whether or not green tea is damaging your sleep is to listen to your body and specifically look at how easily you fall asleep and how refreshed you wake up.
While drinking tea early in the day but not in the first 90 minutes after waking up is the most important timing rule to keep in mind, there are three more things to consider.
One of them is exercise. If you wish to use the stimulant to increase exercise performance, take it at least 45 minutes before your exercise session. If you exercise in the evening, forget about this recommendation.
The other thing to consider is spreading tea and not consuming all of it at the same time. This will make the energy-increasing effects more stable throughout the day and it will also lower some of the potential side effects.
The last thing to consider is green tea’s effect on iron and zinc absorption. The catechins, tannins, and caffeine in tea can decrease the bioavailability of iron and zinc which could be both an issue and a benefit, depending on how much iron you have in your bloodstream. If you experience symptoms of anemia, do not ingest caffeine close to your meals.
Interactions with other supplements
Caffeine Green tea catechins, such as EGCG, negate some of the potential side effects of caffeine. The combination also appears to be quite effective for fat loss and a few other effects.
Vitamin C Vitamin C appears to enhance the absorption of tea catechins. It can also protect iron from becoming less bioavailable after you drink tea.
CoQ10 Ubiquinone (a metabolite of CoQ10) increases the anti-oxidative effects of EGCG. Catechins in tea also increase CoQ10’s ability to protect the liver during reserpine toxicity.
Turmeric This combination appears to be very effective at preventing or slowing down the growth of colon cancer.
Danshen This Chinese herb increases the half-life of caffeine by 12-16%.
Iron Since green tea catechins, caffeine, and tannins inhibit the absorption of iron by around 10-50%, they may increase your iron needs. If you notice a sign of deficiency or are prone to it, you may want to increase your iron intake and supplements are one way to go. Do not take iron together with green tea or its catechins though, so the absorption isn’t decreased. Also, do not take this as a call to action to start taking iron if you are not deficient because some people tend to have too much iron in their system. Excess iron in the blood can also lead to health complications.
Zinc The same that has been said about iron also applies to zinc. The only difference is that zinc absorption does not get affected by the catechins in tea, but both tannins and caffeine do lower zinc absorption.
Phytic acid Phytic acid (found primarily in nuts, seeds, legumes, and grains) and green tea have been shown to significantly decrease tumor growth when ingested together. So far, the tumor-suppressing effect has only been found in the colon but likely applies to other tumor cells as well.
Lemon Lemon (probably because of the citric acid in it) significantly increases the beneficial effects of tea.
Omega 3 Omega 3 fatty acids increase the bioavailability of EGCG and other catechins in tea.
Piperine Piperine (found in black pepper) seems to increase the bioavailability of green tea catechins to at least some extent. However, more studies are needed to confirm this effect.
L-Theanine L-theanine naturally occurs in tea and can reduce the negative effects of caffeine, including anxiety, jitteriness, and even the potential negative impact on sleep to some extent. If you consume a lot of caffeine, it is highly recommended to combine it with 100-200 mg of l-theanine. Besides theanine’s ability to lower the side effects of the stimulant, the combination is also very effective at improving focus and attention. It has also been shown to protect people from cognitive decline to some extent.
Quercetin Quercetin can increase the absorption of EGCG and other catechins.
Soy isoflavones The combination likely leads to AMPK activation, which may have a positive effect on increasing lifespan.
Taurine When used together, the effects of both green tea (especially the caffeine in it) and taurine get slightly enhanced.
EGCG Additional EGCG can reduce the blood pressure increase from caffeine. It also reduces its effects on adrenaline and noradrenaline. Overall, EGCG leads to a smoother peak of the stimulation effect.
Whey protein Whey protein negates many of the beneficial effects of green tea catechins.
Alcohol As a stimulant, caffeine can negate the depressant effect of alcohol, making the drinker feel as if he is not impaired. This makes the drinker likely to drink more.
Propranolol Propranolol has been shown to reduce caffeine’s thermogenic effects, making it less effective for fat loss. On the other hand, propranolol can reduce sperm motility which is countered by caffeine.
Other sources of caffeine
Caffeine supplements – Even though many of the benefits above also apply to caffeine supplements, it is not the preferred way to take the compound because you would miss out on all of the other benefits of guarana, tea, coffee, or other sources. Caffeine supplements are rarely worth it unless you are a serious athlete or hate the taste of caffeinated beverages. Even in those cases, guarana supplements or tea and coffee extracts would be much better.
Guarana– Guarana (Paullinia cupana) is a plant traditionally used in and around the Amazon rainforest. The seeds of Paullinia contain more caffeine than coffee or any other plant in the world (3.6-5.8% of their dry weight is caffeine).
Coffee – The caffeine content of coffee varies greatly from cup to cup. Generally, a regular cup of coffee contains between 40 and 180 mg, with the average being around 135 mg. So if you drink coffee that is not too intense, you can probably count one cup as 135 mg. Decaffeinated coffee only contains about 2 mg per cup.
Green tea – An average cup contains around 20 mg of caffeine and 50-100 mg of EGCG.
Decaf green tea – Decaffeinated green tea contains on average 1-2 mg of caffeine and 60 mg of EGCG per cup.
Matcha green tea – Matcha is significantly higher in both caffeine and catechins than other forms of green tea. Or, more precisely, you get to consume more of these since you swallow the powder.
Pu-Erh – Pu-Erh is comparable to black tea as far as its caffeine and catechin content.
Black tea – Black tea contains about 2 times as much caffeine as green tea, so on average 40 mg. Unfortunately, it is not very high in catechins and only contains around 10 mg of EGCG per cup.
Oolong tea – Oolong tea’s caffeine and catechin content is somewhere between green and black tea. An average cup contains 30 mg of caffeine and 40 mg of EGCG.
White tea – White tea has around the same level of catechins as green tea and contains an average of only 10 mg of caffeine per cup. This is a very good thing because it allows you to drink a lot of white tea and reap more benefits connected to EGCG and other catechins in it.
Yellow tea – This type is extremely similar to white tea.
Cacao – Cocoa powder has around 0.21% caffeine by weight. Therefore, one gram contains an average of 2.1 mg.
Yerba maté – Yerba maté has a much higher caffeine content than regular tea. Typically, an average cup of yerba maté contains about 80 mg of caffeine.
Soda and energy drinks – This is undoubtedly the worst way to consume caffeine, mainly because of the sugar and/or artificial sweetener content in these drinks. There are brands on the market that sell relatively harmless energy drinks sweetened with stevia, xylitol, or erythritol. While these are definitely a better choice than regular energy drinks, they are still not better than coffee, tea, or other natural sources. As for caffeine content, energy drinks almost always contain around 30 mg per 100 ml, and Coke contains around 10 mg per 100 ml.
To determine what the healthiest type of tea is, we need to consider 2 things: 1) The benefits per cup 2) The caffeine content
For example, people often compare green and black tea together. Their polyphenol content is roughly equal (green tea is much higher in catechins but black tea contains more theaflavins). Because of that, the long-term benefits per cup appear to be similar. However, green tea has on average 2 times less caffeine in it, making it 2 times more beneficial per mg of caffeine.
Caffeine itself is not necessarily a harmful compound and it is responsible for many of the benefits of tea. However, it limits the amount of tea you can safely drink per day (especially when it comes to the high-caffeine types, such as black tea and Pu-Erh).
So which tea type is the best depends on whether you are looking for the most benefits per cup or benefits per amount of caffeine.
If you are looking for the most benefits per cup, matcha gyokuro appears to be the best choice. Gyokuro is a type of green tea that appears to be the highest in EGCG and other catechins. Whichever type of green tea you are consuming, choosing a powdered form (matcha) will allow you to get the most catechins out of it.
If you are looking for the most benefits per 1 mg of caffeine, matcha gyokuro is still one of the best types but it does not deserve the #1 spot. The winner in this category would probably be some form of yellow or white tea since these are almost just as high in the beneficial compounds as green tea but much lower in caffeine (typically around 10 mg per cup). This allows you to safely drink almost as much white/yellow tea as you wish and thus reap a lot more benefits.
Oolong tea is somewhere between green tea and black tea as far as the caffeine content and health benefits go.
As for Pu-erh tea, it is almost identical to black tea as far as its composition and health effects. The main difference between the two is their l-theanine content. Black tea contains around 25 mg of l-theanine per cup, while pu-erh contains little to no l-theanine.
So to summarize, matcha green tea, white tea, and yellow tea can all be considered the healthiest types, depending on your definition of healthiest. However, that doesn’t take away from other types of tea, as they can be more useful for specific purposes.
Also, we did not take into consideration herbal teas as that is a completely different category with vastly different effects.
Where to buy green tea
Since tea is one of the most popular beverages, you can find it in almost any food store.
Amazon is also a great option for ordering green tea in many countries. They offer some very affordable tea that is backed by many positive reviews. Also, you can choose from a wide range of brands there without having to spend time searching through other markets on the internet.
FAQ
An average cup of green tea has 20 mg of caffeine. However, some types, such as sencha, contain more caffeine. Sencha contains, on average, 27 mg to 41 mg of caffeine per cup. Gunpowder green tea contains even more, roughly 35-40 mg a cup.
It is important to note that you do develop tolerance to caffeine in tea over time and the higher the dose you are taking, the sooner the tolerance will develop and the more intense it will be. Fortunately, you can get rid of the tolerance by going through a caffeine cycle at least once in a while.
Probably the best caffeine cycling protocol to reset your tolerance for the compound is going cold turkey for a week every 3 months. While the week without the stimulant will probably be unpleasant (most people experience headaches, low energy, and get agitated very easily), the pain is worth going through if you wish to maximize the benefits of caffeine.
If you have been consuming caffeine every day or nearly every day for many years, you will probably need more time than a week to get back to baseline and become fully sensitive to the stimulant. In the most extreme cases, this takes up to 3 months. However, 1-2 weeks should lead to most of the restorative effects.
Also, if you wish to get through the withdrawal phase faster, one very effective way to do it is “sleep banking”. Basically, what that means is you try to sleep as much as possible (even if it’s 12-16 hours a day) to allow your body to get back to baseline faster.
The longer you steep green tea, the more of the beneficial compounds (such as catechins) will get released into the water. Therefore, longer is generally better as far as health goes. The only problem is that the more tannins get released into the water, the more bitter the taste will be.
Caffeine is the chemical that releases the fastest so if you do not care about the health benefits of tea but want it to taste good and reap the benefits of caffeine, steeping the tea for 3 minutes should be enough for the caffeine to dissolve in water.
The first effects will become notable around 15 minutes after ingestion. You can expect the peak effect to occur around 45-60 minutes after you drink green tea.
Green tea does lose potency over time. Usually, you can expect the tea to be just as fresh as when you bought it for 6-12 months if you store it well.
Keep the tea in a cold, dark, and dry place and it should remain just as potent for a few months or even years.
One cup contains on average 25 mg of L-theanine.
The half-life of caffeine can be anywhere from 1.5 hours to 9.5 hours, depending mainly on your genes. The average half-life is 5-6 hours. Therefore, it takes a few days for the compound to fully leave your system but the effects will be less and less potent.
As for the catechins in green tea, the peak plasma concentrations of EGCG are reached 1-2 hours after you take it. After that, the concentrations start slowly diminishing until they become undetectable, which usually takes around 24 hours.
The main compound that can cause trouble if you drink high amounts of tea is caffeine.
Doses of 20-40 mg/kg of caffeine have been shown to be toxic and are not recommended to anybody. This would mean 1-2 cups for 1 kilogram of body weight. So you do not have to worry about caffeine toxicity from tea.
However, even though it is nearly impossible to overdose on green tea, drinking too much can lead to anxiety, agitation, sleep problems, and all the other side effects connected to caffeine.
Therefore, it is recommended to stay below 10 cups a day.
Also, if you are pregnant or suffer from cardiovascular health issues, you may want to decrease your caffeine intake even further.
To stay on the safe side, you want to drink no more than 8 cups a day.
Here is a brief explanation of why the withdrawal happens:
Caffeine has a similar molecular structure to that of adenosine and is, therefore, able to enter and fill adenosine receptors. When adenosine molecules enter the receptors, they send a signal to your body that it is time to sleep, which makes you relaxed and sleepy. When caffeine fills the receptors instead, adenosine molecules cannot enter the receptors until caffeine leaves them, which postpones the sleep-inducing effect of adenosine. Because of this, your body starts creating more and more adenosine receptors that adenosine can fit into, making you more reliant on caffeine. When you stop consuming caffeine, the adenosine receptors will start getting broken down, which leads to the symptoms of withdrawal, such as headaches, fatigue, and getting angry and annoyed easily.
Fortunately, it takes only around a week to get rid of the excess adenosine receptors.
It takes about a week to get through the withdrawal and become fully sensitive to the stimulant again. The first days of the withdrawal phase are usually the worst but once you get through them, the symptoms of withdrawal will gradually get less and less intense.
There are many brands and types of green tea on the market and they all taste slightly different. But in general, the tea has a bitter taste. The longer you steep it in water and the higher the temperature of that water, the more bitter it will taste.
Gyokuro is the type that appears to be the highest in EGCG and other catechins. Whichever type of green tea you are consuming, choosing a powdered form (matcha) will allow you to get the most catechins out of it. Therefore, matcha gyokuro appears to be the richest type in EGCG and catechins in general.
People usually recommend a temperature of 80°C or 176°F. This is a great recommendation if you care about the taste of green tea more than about its benefits.
However, if you prioritize the beneficial health effects and do not care about the taste as much, a higher temperature is a way to go because it will allow more of the beneficial compounds to get dissolved in water. While some compounds will get destroyed by high heat, this is not a big concern and a higher temperature is still a better way to go.
So to optimize the health effects of green tea, pour boiling water on it.
The exception to this rule is matcha green tea because you are going to ingest the leaf powder either way. In that case, 70°C is probably the best way to go.
None of them. The only way green tea could improve hair growth is by decreasing testosterone and DHT levels in the body. Green tea is not very effective in this regard.
Most green tea on the market comes from China, which is where the Camellia Sinensis plant originated from. Other big producers of tea include Japan, Vietnam, Indonesia, India, and Russia, but all of these combined produce less tea than China alone.
It is an extract of green tea polyphenols. Specifically, catechins, such as EGCG, are the most predominant compounds in the extracts. Most of them are around 50% EGCG and contain little to no caffeine. However, some extracts do contain caffeine as well.
Both of these have the potential to be beneficial for long-term health. Which of these beverages is better for you depends on many variables.
One important factor to take into consideration is that coffee has considerably more caffeine per cup than tea. Compared to green tea, one cup of coffee is usually 2-7 times higher in caffeine.
As for the health benefits, one cup of average coffee can be just as beneficial as one cup of average tea. However, this means that tea is significantly more beneficial than coffee per mg of caffeine.
So if you look at benefits per cup, the difference is not too big and will depend on the quality and type of coffee or tea you are drinking. If you look at benefits per caffeine, tea is almost always going to be a clear winner.
Also, beware that this answer is extremely simplified. Coffee has a considerably different chemical structure than tea and leads to different health effects. This answer applies to general health but not to all areas of health. In some areas, tea is significantly more effective and in other areas, the opposite is the case.
No, it is perfectly fine to drink green tea, including matcha, during a fast. In fact, the antioxidants and caffeine in it are actually going to increase some of the benefits of fasting. One caveat to keep in mind is that drinking tea with sugar, milk, or certain artificial sweeteners in it would certainly break a fast.
References
Most of the information provided in this guide is based on scientific research that can be found and verified in the PubMed medical library. We excluded from consideration studies that are either confounded or have a high conflict of interest.
Anecdotal evidence (from reports on Reddit, YouTube, and other sources) is also taken into account unless it contradicts scientific research.
