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Why does green tea give me a headache but coffee doesn t?

If you’re a tea drinker, you’ve probably experienced it – that dull, throbbing headache that comes on after a few cups of green tea. But switch to coffee, and the pain fades away. What gives? Why does green tea trigger headaches in some people, while coffee doesn’t seem to cause the same reaction?

The Caffeine Difference

The most obvious difference between green tea and coffee is caffeine content. An 8oz cup of green tea contains around 25mg of caffeine, while a cup of coffee packs around 100mg. So if caffeine was the culprit, you’d expect coffee to cause more frequent and severe headaches, right? Wrong.

It turns out that the caffeine in green tea may be more likely to cause headaches than the caffeine in coffee for a few reasons:

  • The caffeine in green tea is absorbed more slowly, so the stimulant effect is prolonged.
  • Coffee contains antioxidants and other compounds that may counteract the headache-promoting effect of caffeine.
  • Caffeine headaches are more likely if you don’t regularly consume caffeine. Many coffee drinkers build up a tolerance.

Amines in Green Tea

In addition to caffeine, green tea contains a group of stimulants called amines. These include:

  • Theophylline
  • Theobromine
  • L-theanine

Research suggests that the amines in green tea can alter blood flow in the brain, triggering vascular changes that may lead to headaches in sensitive individuals:

Study Findings
Schmidt et al. 2009 Theophylline causes cerebral vasodilation in rats.
Chung et al. 2012 L-theanine administration results in increased alpha activity and decreased delta/theta activity in the human brain.
Giles et al. 2012 Theobromine increases brain activation but decreases blood flow velocity in the middle cerebral artery.

The combined stimulating effects of these compounds appear more likely to trigger headaches than caffeine alone.

Flavonoids in Green Tea

Green tea is rich in plant compounds called flavonoids, including catechins like epigallocatechin gallate (EGCG). While flavonoids are generally considered healthy antioxidants, they may contribute to headaches in those sensitive to their effects by:

  • Altering platelet function
  • Influencing nitric oxide pathways
  • Changing serotonin receptor activity

This may amplify the vascular effects of amines present in green tea.

Study Proposed Mechanism
Oyama et al 2011 Catechins inhibit platelet aggregation
Lorenz et al. 2004 EGCG modulates nitric oxide synthase
Vignes et al. 2006 Green tea flavonoids bind serotonin receptors

Tannins in Green Tea

Tannins are another group of polyphenols found in green tea. These bitter compounds can reduce absorption of vitamins and minerals, including iron. Deficiencies in iron, B vitamins, and other nutrients due to excessive tannin consumption may contribute to headaches.

Dehydration and Hypoglycemia

Drinking large quantities of fluids containing caffeine and tannins has diuretic effects, meaning it increases urine output. This can lead to dehydration and electrolyte imbalances that may trigger headaches.

In addition, green tea is generally consumed without added sugars and in a fasted state first thing in the morning. This can contribute to drops in blood glucose that can also precipitate headaches in susceptible individuals.

mint is suggested what you think?

Adding mint to green tea is an interesting suggestion that may help reduce headaches in some people. Here are a few potential benefits of pairing mint with green tea:

  • Mint provides menthol, which has analgesic effects and may help relieve headache pain.
  • The strong minty flavor can help mask the bitterness of tannins in green tea.
  • Mint is calming to the digestive tract and could counteract any nausea associated with green tea headaches.
  • The additional fluid and hydration from mint tea could prevent dehydration.

On the other hand, mint contains its own group of polyphenols and volatile compounds that could potentially exacerbate headaches in those sensitive to certain phytochemicals. But since mint is generally calming and has pain-relieving properties, the benefits may outweigh any risks for many people. Adding some fresh or dried mint to your cup of green tea is certainly worth a try if you regularly get headaches from drinking it!

Other Tips to Prevent Green Tea Headaches

Here are a few other suggestions to help you enjoy green tea without the unwanted headache side effect:

  • Drink smaller, more frequent cups rather than large volumes at once.
  • Choose lower caffeine Japanese green tea varieties.
  • Always drink green tea with food to prevent hypoglycemia.
  • Increase hydration by pairing green tea with herbal teas like chamomile.
  • Take a painkiller beforehand if you know green tea triggers headaches.
  • Supplement with B vitamins, iron, and magnesium to compensate for any inhibitory effects of tannins.


So in summary, green tea is more likely to cause headaches than coffee due to differences in:

  • Caffeine content and absorption
  • Amine stimulants
  • Flavonoids and tannins
  • Effects on hydration and blood sugar

If you’re sensitive to green tea headaches, mint may help by reducing nausea, boosting hydration, and providing analgesic effects. But dietary and lifestyle tweaks like avoiding fasting, increasing water intake, and possibly taking supplements may also be needed to allow you to enjoy green tea without pain.