13 Amazing Benefits Of Green Tea And Its Side Effects

Manage stress with a cup of this refreshing tea to enhance your health to the next level.

Medically reviewed by Monica Auslander MorenoMonica Auslander Moreno, MS, RDN
By Charushila BiswasCharushila Biswas, MSc (Biotechnology), ISSA Certified Fitness Nutritionist  • 

Green tea is the most popular health drink in the world (1). It is obtained from the Camellia sinensis plant. Green tea benefits your health as it contains catechins, a beneficial compound with many health advantages (2), (3). This post discusses 13 benefits of green tea and why you should drink it regularly. Keep scrolling.

protip_icon Know Your Ingredient: Green Tea

What Is It?
A type of tea made by brewing unoxidized leaves of the Camella sinensis plant.

What Are Its Benefits?
May aid in weight loss, help fight cancer, regulate blood sugar, control cholesterol levels, improve brain functions, and promote overall wellness.

Who Can Consume It?
All except children under 2 years, pregnant women, and those experiencing anxiety.

How Often?
Can be consumed regularly.

Its high caffeine content may cause an allergic reaction in people with caffeine sensitivity.

Green Tea Facts

  • Green tea was discovered in China in 3000 B.C. (4). It was popularized in Japan and India by Buddhist monks who travelled and drank green tea for meditation and health benefits.
  • All teas (black tea, oolong tea, matcha tea, etc.) are obtained from the same plant, i.e., Camellia sinensis. However, green tea is less processed and oxidized than black and Pu-erh teas. Hence, it is richer in phenolic compounds and other nutrients (5), (6).
  • Green tea is loaded with antioxidants called There are four types of catechinsi  XCompounds found in teas and legumes that provide a rich source of antioxidants and help prevent various chronic diseases. (7):
  1. Epicatechin (EC)
  2. Epicatechin-3-gallate (ECG)
  3. Epigallocatechin (EGC)
  4. Epigallocatechin-3-gallate (EGCG)

Of these four, EGCG is the most effective in fighting various diseases and health issues.

protip_icon Fun Fact
Green tea was discovered by the Chinese Emperor Shen Nung when accidentally the leaves of the Camellia sinensis plant blew into his cup of drinking water. Not noticing the change in the color, he drank it and was enchanted by its refreshing flavor and taste.

Let’s find out why green tea is good for you.

13 Green Tea Health Benefits  – Backed By Science

1. Green Tea EGCG Aids Weight Loss

Green tea aids weight loss

Image: Shutterstock

About one-third of the world population is overweight or obese (8). Thankfully, the EGCG in green tea aids weight loss (0.6 kg – 1.25 kg), decreases body fat (0.5 kg – 1.8 kg) and helps reduce waist size (9). Here’s how green tea may help you lose weight and get rid of belly fat:

  • Boosts Metabolism And Fat Oxidation – Green tea catechins and caffeine kick-start metabolism and induce fast fat oxidation (fat broken down into fatty acids). A study found that green tea extract (GTE), high in EGCG content, stimulated genes that breakdown fat (10). Another study found that green tea EGCG reduced 37% of visceral fat by decreasing lipid absorption (11).
  • Induces Thermogenesis –Green tea extract (GTE) induces thermogenesis (body heat production), which leads to weight loss (12). The caffeine and catechins in green tea also aid prolonged thermogenesis by inhibiting the enzyme catechol-o-methyltransferase (13).
  • Reduces Hunger – The EGCG and caffeine in green tea help reduce appetite by regulating the hunger genes and hormones (14). Scientists found EGCG reduced the levels of the hunger hormone, leptini  XA hormone produced by fat cells that regulates body weight and energy by suppressing hunger and regulating food intake. . This led to a 60% decrease in food consumption and 21% body weight loss in laboratory rats (15).
  • Improves Physical Performance – Green tea EGCG and/or green tea extract help reduce fatigue and boost energy in athletes. This, in turn, improves physical activity, helps focus on performance, and reduces recovery time (16). Green tea extract also helps prolong exercise endurance by 8-24% (17).
  • Zero Calories – Green tea has zero calories. People on a weight loss diet do not have to worry about consuming too many calories if they drink 2-3 cups of green tea per day.

Bottom Line – Green tea is good for weight loss as it boosts metabolism, helps melt fat, and improves physical performance.

2. Green Tea Antioxidants May Help Fight Certain Cancers 

Uncontrolled cell division and spread of abnormal cells cause cancer (18). It is the second leading cause of death in the US (19).  Green tea’s powerful antioxidants may help fight cancer by scavenging harmful free oxygen radicals that cause oxidative damage to the cells and DNA.

  • Breast Cancer – EGCG helped reduce the risk of breast cancer by 19% and recurrence by 27% (20). The anticancer properties of green tea may help reduce the expression of breast cancer and reactive oxygen species (ROS) levels (21). EGCG reduces the activity of oncogenes (cancer genes) and cancer cell proliferation (22).
  • Colon Cancer – Green tea also helps reduce the risk of colon cancer in non-smokers. An increase of 2 g of green tea intake showed a 12% reduction of colon cancer risk (23). In another study, scientists found people who drank green tea for six months had a 17% reduced risk of digestive cancers (24).
  • Nasopharyngeal Cancer – The EGCG found in green tea reduces the risk of nasopharyngeal (head and neck) cancer. It prevents cancer cell proliferation, migration, and cancer cell death (apoptosis) (25).
  • Cervical And Prostate Cancers – EGCG suppresses cervical cancer cell proliferation (26). Drinking at least five cups of green tea per day helps with prostate cancer prevention in men (27).
  • Lung Cancer – Drinking at least three cups of green tea per day may also reduce the risk of lung cancer in smokers (28). EGCG helps halt lung cancer cell proliferation and detoxify environmental toxins and cancer-causing agents (carcinogens) (29), (30).

Bottom Line – Green tea EGCG is a powerful anticancer agent. It reduces oxidative damage, prevents uncontrolled cell growth and migration, and induces cancer cell death.

3. Green Tea May Reduce Insulin Resistance And Risk Of Diabetes

Green tea may reduce risk of diabetes

Image: Shutterstock

Diabetes is a global epidemic, and by 2045, it may affect about 629 million people (31). People with diabetes have high blood sugar levels – due to the body’s inability to produce enough insulin (type 1 diabetes) or insulin resistance (type 2 diabetes) (32).

Epigallocatechin gallate (EGCG) increases satiety,  aids weight loss, reduces waist circumference, increases insulin sensitivity, and regulates blood sugar levels  (33), (34).

Consuming three cups of green tea per day can reduce the risk of type 2 diabetes by 42% (35). 

Bottom Line – Green tea catechins help reduce the risk of type 2 diabetes by aiding weight loss, increasing insulin sensitivity, and lowering serum blood glucose levels.

4. Green Tea Antioxidants May Improve Cardiovascular Health 

Green tea may improve cardiovascular health

Image: Shutterstock

Cardiovascular diseases (CVD) like heart disease, stroke, and cardiac arrest are the leading causes of deaths every year (36). These diseases are caused due to high LDL cholesterol and serum triglycerides, obesity, and high blood pressure. Green tea helps in the following ways:

  • May Lower LDL Cholesterol – In a study, EGCG lowered LDL cholesterol (cholesterol deposits on arterial walls blocks the blood flow) by 9. 29 mg/dl (37).
  • May Reduce High BP – Drinking green tea helped reduce visceral fat accumulation by 17.8%, decreased cholesterol absorption and LDL oxidation, and reduced blood pressure (38), (39), (40).
  • Low doses of green tea also help prevent atrial fibrillationi  XA condition in which abnormal or rapid heartbeat leads to clotting of blood, increasing the chances of heart failure. and improve heart health (41).

Bottom Line – Green tea may help prevent the risk of cardiovascular diseases like heart attack and stroke by lowering total and LDL cholesterol levels, reducing high blood pressure, and aiding weight loss.

5. Green Tea Catechins May Improve Brain Function

Scientists have found that EGCG and l-theanine (an amino acid found in green tea) have antioxidant properties (42). These compounds help protect your brain health and improve brain function, cognition, mood, and attention (43). Here’s how green tea helps:

  • May Prevent Brain Dysfunction – The neuroprotective properties of green tea induce neuritogenesis (synthesis of new neurites) and help suppress brain dysfunction (44).
  • Can Improve Memory – Studies show that green tea consumption can help improve memory and reduce the risk of Alzheimer’s and Parkinson’s (45), (46).

Bottom Line – The EGCG and l-theanine in green tea improve brain function, mood, attention, and protect from neurodegenerative diseases.

6. Green Tea EGCG Is Great For Skin And Hair 

  • Delays Skin Aging – Green tea antioxidants help protect the skin from UV rays, oxidative stress, photodamagei  XThe adverse effects of UV rays on the skin that result in premature aging. It also increases the risk of skin cancer. , and skin cancer (47), (48). Green tea antioxidants improve skin hydration, have anti-aging properties and help delay collagen aging, thereby keeping your skin looking young (49).
  • Lowers Skin Inflammation – The anti-inflammatory property also protects the skin from inflammatory reactions and skin conditions like acne, atopic dermatitis, keloids, warts, hirsutismi  XExcess growth of hair on a woman’s face due to the presence of androgen, a male sex hormone. It can also be seen on the back and chest. , candidiasis, etc. (50).
  • Prevents Hair Fall – A study published in the Journal of Cosmetic Science showed that the application of green tea extract on the scalp helped reduce scalp greasiness (51). Green also helped reduce androgenetic alopecia (male pattern baldness) or hair loss (52).
  • Makes Hair Smooth And Shiny – Green tea may stimulate hair growth by inhibiting Dihydrotestosterone (DTH), and it also softens hair (53), (54). It contains polyphenols and vitamins C and E, which are known to promote lustrous hair.
protip_icon Did You Know?
You can also place chilled green tea bags under your eyes to reduce puffiness and dark circles and get a refreshing look.

Bottom Line – The antioxidant and anti-inflammatory polyphenols in green tea help maintain good skin and hair health.

7. Green Tea Antioxidants May Reduce PCOS Risk

Polycystic ovarian syndrome (PCOS) is a hormonal disorder in women (55). High amounts of androgens (male hormones), irregular periods, and excessive facial hair are a few characteristics of PCOS. Green tea may help in the following ways:

  • Aids Weight Loss – Research shows that overweight or obese women (who are prone to develop PCOS) who drink green tea can prevent the risk of PCOS by losing weight (56).
  • Prevents Hormonal Imbalance – Another study confirmed that green tea helps reduce testosterone levels and decreases fasting insulin levels (57).
  • Reduces Cysts – Green tea polyphenols can also help reduce the number of cysts and cyst layer thickness (58).

Bottom Line – Green tea antioxidants may help women with PCOS by reducing total body fat, testosterone levels, number of cysts, and cyst layer thickness.

8. Green Tea Catechins May Reduce High Blood Pressure

Green tea may reduce high blood pressure

Image: Shutterstock

Complications from high blood pressure or hypertension claim about 9.4 million lives per year (59). Poor diet, inactivity, age, genes, and gender may cause high blood pressure. Green tea helps in reducing high blood pressure and relaxation of the smooth muscles.

  • Reduces High Blood Pressure – Scientists found that green tea or green tea extract (GTE) could reduce systolic and diastolic blood pressure in overweight and obese adults (60). Another study confirmed that green tea helped lower systolic blood pressure by 6.6% and diastolic blood pressure by 5.1% (61).
  • Relaxes Smooth Muscles – The powerful antioxidant and anti-inflammatory properties of green tea help relax smooth muscle contraction, reduce inflammation, and lower vascular oxidative stress, thereby reducing high blood pressure (62).

Bottom Line – Regular consumption of green tea helps reduce systolic and diastolic blood pressure.

9. Green Tea Catechins May Reduce Inflammation And Arthritis

Green tea may reduce inflammation and arthritis

Image: Shutterstock

Inflammation is the body’s first response to injury, infection, or autoimmune diseases. It paves the path for healing. But chronic or constant inflammation may cause weight gain, allergies, diabetes, arthritis, cardiovascular diseases (CVD), and chronic obstructive pulmonary disease (COPD), etc. (63). Here’s how green tea helps manage inflammation:

  • May Reduce Inflammation And Diseases – Green tea’s anti-inflammatory and antioxidant properties help reduce the inflammatory markers in Inflammatory Bowel Disease (IBD), gastric cancer, arthritis, inflammation-induced weight gain, and neurodegenerative disorders (64).
  • Helps Manage Arthritic Inflammation – According to the Arthritis Foundation, EGCG in green tea has 100 times stronger antioxidant activity than vitamins C and E(65). Consuming 4-6 cups of green tea may help reduce swollen joints and inflammation in people with rheumatoid arthritis (66). EGCG inhibits pro-inflammatory molecules and inflammatory signalling pathways that lead to inflammation and arthritis (67), (68).

Bottom Line – Green tea’s anti-inflammatory properties may help reduce chronic inflammation, swelling, redness, and joint pain by blocking inflammatory pathways.

10. Green Tea May Reduce Depression And Anxiety 

More than 300 million people deal with depression, and 40 million people with anxiety (69), (70). Green tea can reduce the symptoms in the following ways:

  • Improves Mood – Research studies show that green tea catechins help lower symptoms of depression and anxiety (71), (72). Green tea antioxidants also helped reduce depression in people who had a stroke (73).
  • Reduces Stress Hormones – Green tea polyphenols or catechins work by reducing stress hormones commonly associated with depression and anxiety (74).

Bottom Line – Green tea polyphenols help reduce stress hormones, thereby reducing anxiety and depression and improving mood. It is not without reason that Buddhist monks drink green tea before meditation.

11. Green Tea EGCG Can Fight Bacteria, Fungi, And Virus 

Pathogenic microorganisms like certain bacteria, virus, fungi cause infections and may also claim lives (75).

  • Fights Bacterial Infections – EGCG is a natural antibiotic. Researchers found that the EGCG in green tea could help protect from bacterial infections in the lungs (76). Green tea’s antimicrobial property is effective against oral bacteria, UTI caused by cold, and the notoriously dangerous Bacillus anthracis (anthrax bacteria) (77), (78), (79).
  • Fights Fungal And Viral Infections – Studies have also confirmed that green tea is effective against fungal and viral infections (80).

Bottom Line – Green tea has antimicrobial properties that help reduce the chances of bacterial, fungal, and viral infections.

12. Green Tea Polyphenols Are Good For Oral Health

  • Protects Oral Health – The antibacterial properties of green tea polyphenols also help protect the oral cavity from bacterial infections. Green tea protects oral health by reducing oral cavity oxidative stress due to smoking (81).
  • Improves Dental Health – The anti-inflammatory property of green tea helps reduce inflammation and the risk of periodontal diseasesi  XDiseases that cause damage to the gums, bones or soft tissues surrounding the teeth due to poor oral hygiene. and dental caries (82), (83), (84). Green tea polyphenols improve dental health and reduce the risk of oral cancer (85).

Bottom Line – Green tea’s antimicrobial, antioxidant, and anti-inflammatory properties help reduce the risk of dental caries, oral cancer, and bacterial infections.

13. Green Tea May Boost Immunity And Increase Longevity 

  • May Increase Lifespan – Research showed that people in China who regularly consumed green tea lived longer with as high as 10% reduced risk of mortality (86).
  • May Improve Quality Of Life In The Elderly – Drinking green tea may help strengthen immunity and lower functional disability in the elderly (87), (88).
  • May Reduce Risk Of Death –Green tea consumers who are non-smokers may have reduced risk of death from causes like high cholesterol, depression, stroke, obesity, high blood pressure, and diabetes (89), (90).

Bottom Line – Green tea antioxidants may help boost immunity and increase the chances of living a longer, healthier life.

These are the 13 reasons to drink green tea regularly. On top of these reasons, studies also suggest that green tea helps with bone health and metabolism (92). However, drinking too many cups of green tea at odd times may have a few side effects. Scroll down to know how many cups to drink and when.

How Many Cups Of Green Tea To Drink Per Day?

You may drink three cups of green tea per day. Do not exceed the limit of four cups. Drink green tea 20-30 minutes before lunch, evening workout, and dinner. You may also have a cup of green tea with breakfast.

Avoid drinking it on an empty stomach (drink lime water or just water on an empty stomach). Also, avoid drinking green tea right before sleeping. The caffeine may prevent you from falling asleep. Drink it at least 4-5 hours before bed.

Note: Drink decaffeinated green tea if you are caffeine intolerant.

What will happen if you drink too many cups of green tea per day?

Side Effects Of Drinking Too Much Green Tea

  • May cause liver toxicity and kidney issues.
  • May cause spina bifidai  X A birth defect that results in a gap in the spine and affects the spinal cord before it develops in a baby. in newborn babies (91).
  • May cause insomnia.
  • May cause stomach upset and cramps.

Here are a few more green tea side effects in detail.

As we saw, green tea benefits are backed by research. It can aid in weight loss, reduce cancer, diabetes, and PCOS, and promote cardiovascular health and brain function. It also reduces inflammation and anxiety, improves skin hydration, and boosts immunity. The ideal dosage to reap these benefits is 3-4 cups a day. Do not consume beyond that, as excess intake may cause liver toxicity, kidney issues, insomnia, and an upset stomach.

Frequently Asked Questions

What is harmful about green tea?

The tannins in green tea may cause issues in digestion like constipation, acid reflux, and nausea if consumed in excess.

Who should avoid green tea?

Pregnant women, people with anxiety disorders, heart problems, or stomach ulcers, and children under 2 years of age should avoid drinking green tea.

Key Takeaways

  • Green tea can reduce oxidative stress in the body and increase collagen production, thereby promoting younger-looking skin.
  • Green tea may aid in reducing blood sugar levels in the body, hence preventing diabetes.
  • The antioxidants in green tea may improve memory and reduce skin inflammation.
  • Green tea is known for reducing stress hormones, thereby dealing with anxiety and depression.


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