Green Tea or EGCG

• Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of lower biomarkersa chemical or substance, such as certain proteins or genetic material, that are associated with the presence of cancer or a change in status or prognosis; these markers can be detected in blood, urine, or tissue. Tumor markers are not direct measures of clinical outcomes such as survival or metastasis, and if a therapy or treatment shows an impact only on tumor markers, we cannot surmise that it will affect survival. of cancer among people with breast cancer treated with green tea extracts or EGCG
• Preliminary evidence of higher rate of “best observed complete response” but no evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on histologicalrelating to the study of the structure of cells and tissue seen under a microscope response among women diagnosed with primary and recurrent usual type vulval intraepithelial neoplasia (uVIN) treated with an ointment derived from green tea
• Preliminary evidence of lower mortality among people with epithelial ovarian cancer drinking green tea
• No evidence of major response among people with solid tumors treated with green tea extract in a small trial
• No evidence of an effect on survival among elderly people with acute myeloid leukemia with myelodysplasia-related changes treated with green tea extract in a small trial
• No evidence of an effect on objective tumor responses among people with lung cancer treated with green tea extract in a small trial
• No evidence of an effect on complete histological tumor clearance or tumor size among people with a primary superficial basal cell carcinoma treated with topical sinecatechins ointment in a small trial

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Good or modest evidence of benefit

• Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of lower weight, waist circumference, and body fat among people drinking green tea or beverages containing green tea catechins (not specific to cancer)
• Good evidence of lower fasting blood sugar (glucose), but no evidence of an effect among people drinking decaffeinated green tea or on other glycemic indicators among people drinking green tea (not specific to cancer)
• Good evidence of lower ratio of polyunsaturated fatty acids relative to total fatty acids among men with raised PSA levels advised to drink green tea
• Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of an effect on adiponectina hormone and signaling protein involved in regulating glucose levels and fatty acid breakdown concentrations among people with type 2 diabetes supplemented with green tea (not specific to cancer)
• Modest evidence of a lower marker of inflammation among people with type 2 diabetes drinking green tea (not specific to cancer)
• Modest evidence of lower markers of oxidative stressan imbalance between free radicals and antioxidants in your body in which antioxidant levels are lower than normal; this imbalance can cause harmful oxidation reactions in your body chemistry among smokers drinking green tea (not specific to cancer)

Preliminary evidence of benefit

• Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of lower levels of ghrelin—the “hunger hormone”—among obese women treated with green tea extract (not specific to cancer)
• Preliminary evidence of changes in gastrointestinal hormones that affect digestion and insulin secretion after robotic or laparoscopic subtotal gastrectomy among people with stomach (gastric) cancer drinking green tea
• Preliminary (conflicting) evidence of higher blood total estradiol and bioavailable estradiol among healthy postmenopausal women treated with EGCG (not specific to cancer or diabetes)
• Preliminary evidence of immune activation among elderly people with acute myeloid leukemia with myelodysplasia-related changes treated with green tea extracts
• Preliminary evidence of immune activation among healthy adults treated with green tea capsules (not specific to cancer)
• Preliminary evidence of some lower markers of inflammation among people with prostate or stomach cancer drinking green tea
• Preliminary evidence of lower infiltration of inflammatory leukocytes after a single dose of ultraviolet radiation among people treated with EGCG (not specific to cancer or diabetes)
• Preliminary evidence of a lower marker of systemic oxidative DNA damage but no evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on oxidative DNA damage in prostatectomy tissue among men with prostate cancer drinking green tea
• Preliminary evidence of lower markers of oxidative stress among people with obesity and metabolic syndromea cluster of conditions that occur together, including increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels drinking green tea (not specific to cancer)
• Preliminary evidence of a lower marker of oxidative DNA damage among people sero-positive for both HBsAg and aflatoxin-albumin adducts—risk factors for cancer—treated with green tea polyphenols
• Preliminary evidence of a lower marker of oxidative stress among obese people treated with green tea extract (not specific to cancer)
• Preliminary evidence of a lower marker of oxidative stress, especially among smokers, among people treated with green tea extract incorporated into meat patties (not specific to cancer)
• Preliminary evidence of one lower marker of oxidative stress but not others among healthy non-smoking females treated with green tea extract (not specific to cancer)
• Preliminary evidence of lower markers of oxidative stress after exposure to ultraviolet (UV) radiation among people treated with topical application of EGCG (not specific to cancer)

No evidence of benefit

• No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on serotonin after robotic or laparoscopic subtotal gastrectomy among people with stomach (gastric) cancer drinking green tea in a small study
• No evidence of an effect on coagulation indicators among healthy non-smoking females eating a diet rich in linoleic acid and treated with green tea extract in a small trial (not specific to cancer)
• No evidence of an effect on growth hormones among people drinking green tea or treated with green tea extracts in several studies (not specific to cancer)
• No evidence of an effect on adiponectin concentrations among people drinking green tea or treated with green tea extract  (not specific to diabetes)
• No evidence of an effect on markers of immune activation after robotic or laparoscopic subtotal gastrectomy among people with stomach cancer drinking green tea
• No evidence of an effect on a lower marker of inflammation among people who had undergone complete removal of colorectal adenomas treated with green tea extract in one study
• No evidence of an effect on measures of oxidative stress among people with type 2 diabetes drinking green tea in a combined analysis of studies (not specific to cancer)
• No evidence of an effect on bacterial diversity and community structures among adults treated with green tea capsules in a small study

See How can green tea or EGCG help you? What the research says ›

• Strong evidenceconsistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analyses of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results (this is the CancerChoices definition; other researchers and studies may define this differently) of lower systolic and diastolic blood pressure among people drinking green tea compared to no green tea (not specific to cancer)
• Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of less fatigue after robotic or laparoscopic subtotal gastrectomy among people with stomach (gastric) cancer drinking green tea
• Preliminary evidence of shorter time to gastrointestinal function recovery after robotic or laparoscopic subtotal gastrectomy among people with stomach (gastric) cancer drinking green tea
• Preliminary evidence of lower incidence and less severe diarrhea after radiotherapy among people with abdomen and pelvic malignancy treated with green tea tablets
• Preliminary evidence of less esophagitis during or after chemoradiotherapy among people with lung cancer treated with EGCG before or during chemoradiotherapy
• Preliminary evidence of better oral health scores after oral surgery among people with oral cancer rinsing their mouths with a green tea solution
• Preliminary evidence of less perception of pain although no evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on analgesic use during days 1–4 after robotic or laparoscopic subtotal gastrectomy among people with stomach cancer drinking green tea
• Preliminary evidence of lower incidence of grade 2 or worse radiation-induced dermatitis and lower symptom indexes among people with breast cancer treated with an EGCG solution sprayed to the whole radiation field
• Preliminary evidence of less severe acute radiation-induced skin reactions during whole-breast radiotherapy after surgery among people treated with NPE, a proprietary Camellia sinensis nonfermentatum extract
• Preliminary evidence of shorter hospital stays after robotic or laparoscopic subtotal gastrectomy among people with stomach cancer drinking green tea
• Preliminary evidence of comparable odor control from fungatingbreaking through the skin malignant wounds among people treated with either metronidazole powder or green tea bags as dressings
• Preliminary evidence of lower depressive symptom scores and shorter reaction time of reward responsiveness among healthy people treated with green tea powder
• No evidence of an effect on vomiting after radiotherapy among people with abdomen and pelvic malignancy treated with green tea tablets in a small study

See How can green tea or EGCG help you? What the research says ›

Good or modest evidence of benefit

• Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of esophageal cancer among women drinking green tea, but not men
• Good evidence of a moderately lower risk of liver cancer among people drinking green tea
• Good evidence of moderately lower risk of endometrial cancer among people drinking green tea
• Good evidence of moderately lower risk of ovarian cancer among people drinking green tea
• Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of breast cancer recurrence among people drinking green tea, with some evidence that the benefit may be strongest in earlier stages of cancer
• Modest and somewhat conflicting evidence of a slightly lower risk of breast cancer among people drinking green tea
• Modest evidence of lower mammographic density (a risk factor for breast cancer) only among women aged 50 to 55, but no evidence of an effect on older healthy postmenopausal women treated with decaffeinated green tea extract capsules
• Modest but conflicting evidence of lower risk of stomach cancer among people drinking green tea
• Modest evidence of moderately lower risk of lung cancer among people drinking green tea
• Modest evidence of a moderately lower risk of lymphoid neoplasms (lymphoma, myeloma, and lymphoid leukemia) among people drinking green tea
• Modest but conflicting evidence of lower risk of prostate cancer among people treated with green tea extracts

Preliminary evidence of benefit

• Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of substantially lower risk of urinary tract recurrence among people with bladder cancer or urothelial cancer among nonsmokers, but not among people who had ever smoked, drinking green tea, with higher benefits among people drinking higher levels
• Preliminary evidence of fewer colorectal adenomas among people with colon adenomas treated with green tea extract for 12 months or longer
• Preliminary evidence of lower disease activity indices and higher remission rates among people with mild to moderate ulcerative colitis, a risk factor for colon cancer, treated with oral Polyphenon E
• Preliminary evidence of lower risk of chronic atrophic gastritis (CAG), a precancerous lesion of the stomach, among people drinking large quantities of green tea
• Preliminary evidence of lower fumonisin B1, which induces DNA fragmentation and is linked to liver cancer (hepatocellular carcinoma) and esophageal cancer, among people exposed to FB1 and treated with green tea polyphenols
• Preliminary evidence of substantially higher response of human papilloma virus-infected lesions, a risk factor for genital cancer, among people treated with topical Poly E ointment and/or oral EGCG capsules
• Preliminary evidence of lower risk of oral cancer among people drinking green tea
• Preliminary evidence of lower human T-cell lymphotropic virus type 1 (HTLV-1), a risk factor for adult T-cell leukemia (ATL), among asymptomatic HTLV-1 carriers treated with green tea extract powder
• Preliminary evidence of less sunburn (UV-induced erythema) or DNA damage, a risk factor for skin cancer, among people treated with topical polyphenols including EGCG from green tea
• Preliminary (conflicting) evidence of lower risk of prostate cancer among people drinking green tea

No evidence of benefit

• No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on esophageal precancerous lesions and abnormal cell proliferation among people treated with decaffeinated green tea supplements in a large study
• No evidence of an effect on risk of gynecological cancer as a whole among people treated with green tea extracts in a combined analysis of studies
• No evidence of an effect on HPV infection and low-grade CIN1, risk factors for cervical cancer, among women treated with Polyphenon E in a small study
• No evidence of an effect on symptoms among people with recessive dystrophic epidermolysis bullosa (RDEB), a risk factor for fatal skin cancers, treated with oral EGCG in a small study
• No evidence of an effect on risk of pancreatic cancer among people drinking green tea in combined analyses of studies
• No evidence of an effect on risk of thyroid cancer among people drinking green tea in a combined analysis of studies
• No evidence of an effect on risk of urinary tract cancer among people drinking green tea in a combined analysis of studies

See How can green tea or EGCG help you? What the research says ›

• Used widely by integrative oncology experts
• Used in both Ayurveda and traditional Chinese medicine approaches to treating cancer
• Not yet evaluated in clinical practice guidelines

See How do experts use green tea or EGCG? ›

• Generally safe at lower doses, although some mild side effects are noted
• Some higher risks of cancer especially at higher doses
• May interact with cancer treatments; consult your oncologist about use during chemotherapy
• May interact with other medications; consult your physician before use
• Supervision by a medical professional is highly recommended

See Safety and precautions ›

• Widely available without a prescription
• Low cost to somewhat expensive (below $2000 US/year)

See Affordability and access ›