Are There Any Negative Effects Of Tea? What To Know

Are there any negative effects of tea? For most people, tea is a healthy drink. Still, drinking too much or having it at the wrong time can cause problems.

An 8-ounce cup of tea contains 14 to 60 mg of caffeine, which may affect sleep, increase anxiety, or upset the stomach in some people.

Tea can also reduce iron absorption, especially when consumed with iron-rich meals.

This isn’t about scaring you off your favorite cup. It’s about understanding tea benefits and side effects together, so you can drink smarter.

Tea Side Effects: What You Need To Know?

Concern	Cause	Who’s Most at Risk
Insomnia, anxiety, jitters	Caffeine	Caffeine-sensitive individuals, evening drinkers
Reduced iron absorption	Tannins	Vegetarians, vegans, pregnant women, menstruating women
Acid reflux, bloating, gas	Tannins + caffeine	Those with GERD or sensitive stomachs
Tooth staining	Tannins	Frequent black tea/chai drinkers
Weight gain, blood sugar spikes	Added sugar & milk	Milk tea, chai, and sweet tea drinkers
Skin inflammation/breakouts	Sugar in milk tea/chai	Those prone to acne, high sugar intake
Rare skeletal fluorosis	Fluoride (extreme overconsumption)	Very heavy, long-term tea drinkers (multiple liters/day for years)

1. Caffeine: The Root of Most Tea Side Effects

Most negative effects of tea trace back to one ingredient: caffeine.

Tea is naturally lower in caffeine than coffee, but the amount varies enormously depending on the type of tea, how long you steep it, and the water temperature.

• Black tea: roughly 30–70 mg of caffeine per 8-ounce cup
• Green tea: roughly 20–50 mg per cup
• White tea: roughly 15–40 mg per cup
• Oolong tea: roughly 30–70 mg per cup
• Herbal/rooibos tea: essentially caffeine-free

Research shows tea’s caffeine content can increase by around 29% if you steep it just one minute longer than recommended, which explains why a strongly brewed cup of “regular” tea can hit you almost as hard as coffee.

A 2025 chromatography study also found that using tea bags rather than loose-leaf or teapot brewing produced notably higher caffeine levels in black tea infusions.

Most health authorities, including the Mayo Clinic, consider up to 400 milligrams of caffeine a day safe for most healthy adults, though people who get headaches or feel restless and nervous after caffeine may want to cut back.

This is the science behind most “drinking too much tea side effects” complaints – jitteriness, a racing heart, and anxiety are almost always a caffeine overload issue, not a “tea” issue per se.

What are the side effects of tea from caffeine overload?

• Insomnia and disrupted sleep, especially if consumed in the afternoon or evening
• Increased heart rate or palpitations
• Anxiety, restlessness, and jitteriness
• Headaches (both from too much caffeine and, paradoxically, from caffeine withdrawal if you skip your usual cups)
• Mild physical dependency – some regular tea drinkers report fatigue or irritability if they suddenly stop

2. Tea Effects on the Stomach and Digestion

One of the most searched questions is whether tea causes gas or stomach upset – and the answer is: it can, for certain people.

• Tannins, the naturally occurring plant compounds that give tea its slightly bitter, astringent taste, can irritate the stomach lining, especially when tea is consumed on an empty stomach. This is a major reason behind the disadvantages of drinking tea in the morning before eating anything.
• Acid reflux and bloating: The caffeine and tannins in tea can relax the lower esophageal sphincter, contributing to acid reflux, bloating, and gas in sensitive individuals.
• Milk tea and the stomach: Side effects of milk tea on the stomach are often more pronounced than plain tea because the combination of caffeine, tannins, added sugar, and dairy (which some people digest poorly) can trigger bloating, cramping, or looser stools, particularly in those with lactose intolerance or irritable bowel syndrome.

3. Milk Tea and Chai: Extra Layers of Risk

Milk tea, chai, and other sweetened tea drinks come with disadvantages beyond plain brewed tea because of what’s added to them.

Milk tea disadvantages / milk tea side effects on skin and body:

• Most milk tea and bubble tea recipes are loaded with added sugar — a single cup can easily contain 30–50 grams of sugar, close to or beyond the American Heart Association’s entire daily recommended limit for added sugar.
• Regularly drinking sugary milk tea is linked to weight gain, higher triglycerides, and an increased long-term risk of type 2 diabetes.
• High sugar intake is also one of the more overlooked causes of skin problems — spikes in blood sugar can trigger inflammation and increased oil production, which is part of why “is drinking tea bad for skin” comes up so often in relation to sweetened milk tea rather than plain tea.
• Some studies suggest that combining milk with tea may partially blunt the antioxidant benefits of the tea itself, since milk proteins can bind to catechins (the beneficial plant compounds in tea) and reduce their absorption.

Chai side effects:

• Traditional masala chai is brewed with whole milk and sugar, so it carries the same sugar- and dairy-related concerns as milk tea.
• Chai also tends to be brewed longer and steeped with more tea leaves per cup than a standard cup of black tea, which can push caffeine levels – and the associated jitteriness or heartburn – higher than expected.
• Chai side effects on skin largely mirror milk tea: it’s the sugar and dairy load, not the tea itself, that’s usually the culprit behind breakouts in people prone to acne.

Disadvantages of drinking Lipton tea and English breakfast tea: Lipton tea and English breakfast tea are both robust black tea blends, generally on the higher end of the caffeine spectrum (up to roughly 60–70 mg per cup) and rich in tannins.

This makes them more likely than milder teas to contribute to jitteriness, tooth staining, and iron-absorption issues (see below) if consumed in large quantities or with meals.

4. Tea’s Effect on Iron Absorption

This is one of the most clinically significant, well-documented negative effects of tea.

The tannins (polyphenols) in tea bind to non-heme iron – the type of iron found in plant foods like spinach, lentils, and beans – and can reduce its absorption by as much as 60–70% when tea is consumed alongside a meal.

• This matters most for people who are already at risk of iron deficiency: menstruating women, pregnant women, vegetarians, vegans, and young children.
• The simple fix: avoid drinking tea within an hour of iron-rich meals, and consider having it between meals instead.

5. Side Effects of Tea on Skin

“Side effects of tea on skin” and “is tea harmful for skin” are common questions, and the honest answer is nuanced:

• Plain brewed tea, especially green tea, is actually associated with several skin benefits thanks to its antioxidant (catechin) content, which may help protect against UV damage and inflammation.
• However, excessive tea consumption – particularly sweetened milk tea or chai – can indirectly worsen skin through sugar-driven inflammation and blood sugar spikes.
• Caffeine is also a mild diuretic; drinking large amounts of tea without adequately hydrating with water can contribute to skin dryness over time.
• Tannins in tea can also cause temporary staining on the teeth and, in rare cases of skin contact with concentrated tea (as in some home remedies), mild irritation.

The takeaway: it’s not tea leaves themselves that are “bad for skin,” but sugar, milk, and dehydration that ride along with how many people drink it.

6. Bone and Dental Health

• Fluoride content: Tea plants naturally absorb fluoride from soil, and tea — especially older or lower-grade leaves used in tea bags and brick tea — can be a meaningful dietary source of fluoride. Very high, long-term consumption (several liters a day for years) has been linked in case reports to skeletal fluorosis, a condition causing bone pain and stiffness. This is rare and generally only seen in extreme, sustained overconsumption.
• Tooth staining: Tannins in black tea, chai, and English breakfast tea are well known for staining tooth enamel over time – a cosmetic, not medical, side effect, but a very common complaint.
• On the flip side, moderate tea consumption has also been associated with some protective effects on bone mineral density in several observational studies, so the relationship isn’t purely negative – it’s a dose issue.

7. Green Tea Benefits and Side Effects

Green tea often gets a “healthy halo,” but it isn’t risk-free:

• Green tea benefits: high in catechins (especially EGCG), associated with modest improvements in metabolic health, cardiovascular markers, and antioxidant status.
• Green tea disadvantages:
  • Concentrated green tea extracts (especially in supplement/pill form, not brewed tea) have been linked in rare cases to liver toxicity, and several health agencies have flagged high-dose EGCG supplements as a concern for liver health.
  • Green tea still contains caffeine and tannins, so it carries the same iron-absorption, sleep, and stomach-irritation concerns as other teas, just usually to a milder degree.
  • Drinking green tea on an empty stomach is a common trigger for nausea and stomach discomfort due to its tannin content.

8. Pregnancy and Special Populations

• Pregnant women are generally advised to keep total caffeine intake under 200 mg per day, and tea contributes directly to that tally alongside coffee, soda, and chocolate.
• People with anxiety disorders, acid reflux/GERD, insomnia, iron-deficiency anemia, or certain heart arrhythmias are often advised by their doctors to moderate tea intake specifically because of its caffeine and tannin content.
• Tea can also interact with certain medications, including some antibiotics, blood thinners, and stimulant medications – worth flagging to a doctor or pharmacist if you drink tea regularly and take prescription medication.

9. What Happens If You Drink Too Much Tea?

To summarize the cumulative, dose-dependent effects of drinking tea too much:

1. Sleep disruption and insomnia
2. Increased anxiety, restlessness, or a racing heart
3. Stomach irritation, acid reflux, gas, and bloating
4. Reduced iron absorption over time, raising anemia risk in susceptible people
5. Dependency-related headaches or fatigue if intake suddenly drops
6. Tooth staining
7. For sweetened tea (milk tea, chai, sweet tea): added sugar-related weight gain and blood sugar spikes

And yes – sweet tea deserves its own mention. In the U.S. South in particular, a single glass of sweet tea can carry as much sugar as a can of soda, so the “what happens if you drink too much sweet tea” concern is really a sugar-intake concern layered on top of everything above.

10. So, Is Tea Bad for Health?

Not inherently. The disadvantages of tea are almost entirely about quantity, preparation, and additions – not the tea leaf itself:

• Plain brewed tea in moderate amounts (2-4 cups a day) is considered safe and even beneficial for most healthy adults.
• The real harmful effects of tea show up with excessive caffeine intake, tea consumed on an empty stomach, tea taken alongside iron-rich meals, and – especially – sugary milk tea, chai, and sweet tea consumed in large quantities.
• Herbal teas (which technically aren’t “true tea” from the Camellia sinensis plant) sidestep the caffeine and tannin issues entirely, though they come with their own individual considerations depending on the herb.

Should You Worry About The Negative Effects Of Tea?

For most healthy adults, drinking tea in moderation is unlikely to cause significant side effects.

Most teas contain 14–60 mg of caffeine per 8-ounce cup, well below the recommended daily limit of 400 mg for healthy adults.

Extra caution is warranted if you are sensitive to caffeine, have iron deficiency, are pregnant, or take medications that interact with tea.

Drinking tea with meals can also reduce the absorption of non-heme iron.

If you have high blood pressure, choosing the right type of tea matters. Learn which tea is good for high blood pressure before making it part of your daily routine.

For everyone else, moderate tea consumption is generally a safe part of a healthy diet.