Is drinking tea harmful? What is real and what is repeated

No, for almost everybody, and we are not going to pretend it is medicine either. Two effects are real and worth knowing: tea drunk with a meal reduces how much iron your body takes from the plant foods in that meal, and the caffeine is real caffeine. Most of the rest of what you have been told is either about how the chai was made or not about tea at all.

This is the question we get asked most often by people who are not asking about flavour. Usually it arrives as something somebody said: that chai causes acidity, that milk tea is the worst thing you can drink, that four cups a day is doing something to you. Almost none of it is settled the way it gets repeated, and the parts that are true are rarely the parts people worry about.

We sell tea, so read the rest of this knowing that. We have tried to write the version we would want if we did not.

Is drinking tea harmful?

What is actually in the cup

Black tea is leaves, water, and whatever you add. The three things in the leaf that do anything to you are caffeine, polyphenols (the tannins that give the astringency), and a very small amount of fluoride.

Caffeine is the one people underestimate in both directions. A cup of Indian milk chai made with a level teaspoon of CTC carries roughly a third to a half of the caffeine in a similar cup of filter coffee. It is not nothing. It is also not coffee.

The iron one is real

This is the effect worth actually knowing, and it is the one nobody mentions. The polyphenols in tea bind to iron from plant sources and reduce how much of it your body absorbs from the same meal. This is well established and it is not controversial.

It matters if you are anaemic, pregnant, or eating a mostly vegetarian diet, which describes a large number of people in this country. It matters much less if you are not.

The practical version: do not drink chai with your meal or straight after it. Leave an hour on either side. That is the whole adjustment, and it costs nothing, and it is the only dietary advice in this article.

Caffeine and sleep is real too

Caffeine has a half-life of several hours, which means an evening cup is still measurably in you at bedtime. People vary enormously here and most people know which kind they are. If you sleep badly and you drink chai after four in the afternoon, that is worth testing before you blame anything else.

“Chai causes acidity and ulcers”

Ulcers are caused by H. pylori infection and by certain painkillers, not by tea. That was settled decades ago and it is not a matter of opinion.

The discomfort people describe is usually real, though, and there are two ordinary reasons for it. Caffeine on a genuinely empty stomach increases gastric acid, so chai as the first thing in the morning with nothing else does bother some people. And badly made chai, boiled hard for ten minutes, is harsh in a way that a properly made cup is not. If your chai is bitter, that is a brewing problem with a brewing fix, and it is worth ruling out before you conclude the drink disagrees with you.

“Milk tea is the worst kind”

There is no good evidence that adding milk to tea makes it harmful. What milk does is add whatever the milk adds, and what sugar does is add sugar.

That is the honest version of this concern. If you take three spoons of sugar in each of five cups, the thing worth looking at is fifteen spoons of sugar, not the tea. A cup of chai is not a health food and it is not a hazard; it is a hot drink with some sugar in it, and you already knew what sugar does.

The temperature thing, which is about temperature

In 2016 the International Agency for Research on Cancer classified drinking very hot beverages above about 65°C as probably carcinogenic to humans. This gets reported as “tea causes cancer” and it is not what it says. The finding is about heat damaging the oesophagus, and it applies to any liquid at that temperature: coffee, soup, water.

Fresh chai off the flame is above that. By the time it has cooled enough to drink comfortably, it is below it. This is one of the few places where the ordinary Indian habit is already the safe one, because nobody drinks a cup straight off the stove; it sits, it goes into a smaller glass, it cools. The advice is: wait a few minutes, which you were doing anyway.

“Tea is full of pesticide”

This is the one we cannot wave away, and the honest answer is mixed rather than reassuring.

Tea is a sprayed crop. FSSAI sets the residue limits, the Tea Board’s Plant Protection Code sets which formulations a garden may use at all, and both of them test. The testing finds failures. The Tea Board’s own surveillance of packet teas, released under the Right to Information Act, failed 711 of 1,423 samples in 2024-25 and 835 of 1,764 the year after, in 2025-26. Before anyone reads that as half the tea in India, note what the Board does not publish: it counts residues over the limit, non-permitted chemicals and misleading labelling as one number, has never split them, and has not said how the samples were chosen. It is a warning worth taking seriously and it is not a market failure rate.

Whether any of it reaches your cup depends on the compound rather than the quantity. Residues that dissolve easily in water cross into the brew almost completely, and imidacloprid, thiamethoxam and acetamiprid have been measured transferring at eighty to a hundred per cent. Ones that do not dissolve stay largely in the leaf, under twenty. Those three are neonicotinoids the Plant Protection Code approves against tea mosquito bug, so the comfortable line that it all stays in the leaf is true of some pesticides and false of the ones a garden is likeliest to have used.

Nothing you can do at a kitchen counter detects any of this. The tests that catch added colour and exhausted leaf are useless here, and so is anything else you can do at home. What is left is who you buy from: a named region, an FSSAI licence number on the pack, and an operation small enough to be answerable for a bad lot. That is what we can offer and it is not a laboratory certificate.

How much is too much

There is no line that applies to everybody. The commonly cited caffeine ceiling for healthy adults is around 400mg a day, and lower in pregnancy; on a normal Indian cup that is a lot of chai, more than most people drink. The people who should be more careful are the ones who already know it: pregnancy, iron deficiency, certain heart-rhythm conditions, and anybody whose doctor has said so.

What we are not going to tell you

We are not going to tell you chai is good for your heart, or that it burns fat, or that the antioxidants in it will do anything you can feel. Those claims are regulated in India for good reason, the evidence for tea specifically is thinner than the marketing suggests, and a tea company is the last party you should take them from.

What we will say is narrower and we think it is true: made properly, from decent leaf, chai is a hot drink that a very large number of people have drunk daily for a very long time without it being the problem. If you have a condition, ask a doctor rather than a tea seller. If your chai tastes harsh and you have concluded the drink does not agree with you, try making it properly once before you give it up.