Meta Information
ID:green-tea-extract
Name:
Schema Version:2.4_uniform_evidence_2026_06_18
Created
2026-05-21T22:30:00Z
Model
phase-a-upgrade-claude-sonnet-4.6
Interactions
Target id:
/dietary/fasting-state
Target name:
Fasted State (Empty Stomach)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Taking Green Tea Extract on an empty stomach dramatically increases the bioavailability of catechins like EGCG, which is strongly associated with a higher risk of dose-dependent liver injury.
Actionable advice:
Green Tea Extract should never be taken on an empty stomach; it should always be consumed with food.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Based on these findings, USP included a cautionary labeling requirement in its Powdered Decaffeinated Green Tea Extract monograph that reads as follows: "Do not take on an empty stomach.
Label source:
PubMed: United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts. (PMID 32140423)
Action type:
separate
Target id:
/class/hepatotoxic-agents
Target name:
Hepatotoxic Agents
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
High doses of Green Tea Extract (especially EGCG) can be hepatotoxic, and co-administration with other drugs known to cause liver stress (e.g., high-dose acetaminophen, methotrexate) can synergistically increase the risk of severe liver injury.
Actionable advice:
Green Tea Extract should be avoided with any medication known to be hard on the liver.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Intriguingly, we found that EGCG caused dose-dependent hepatotoxicity on mice under dietary restriction, suggesting the potential combination effects of dietary restriction and EGCG.
Label source:
PubMed: Epigallocatechin Gallate During Dietary Restriction - Potential Mechanisms of Enhanced Liver Injury. (PMID 33584288)
Action type:
avoid
Target id:
/condition/hepatic-impairment
Target name:
Hepatic Impairment
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Individuals with pre-existing liver conditions are at a significantly higher risk of developing severe liver injury from Green Tea Extract supplementation.
Actionable advice:
Green Tea Extract should be avoided completely with any known liver disease.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Do not use if you have a liver problem and discontinue use and consult a healthcare practitioner if you develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice (yellowing of the skin or eyes).
Label source:
PubMed: Toxicology reports (2020)
Source url:
Exact phrase from label:
Ashwagandha, kava kava, green tea extract, skullcap, turmeric, and valerian have known idiosyncratic hepatotoxic potential and may complicate the liver transplantation course. Multiple supplements reportedly carry a lower risk of hepatotoxicity, though evidence for widespread use in those at risk for or with hepatic impairment is limited.
Label source:
PubMed: Current psychiatry reports (2024)
Action type:
avoid
Target id:
/intervention/bortezomib
Target name:
Bortezomib (Velcade)
Severity:
major
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Polyphenols in green tea, including EGCG, can bind to and inactivate bortezomib, a proteasome inhibitor used in cancer therapy, rendering the treatment ineffective.
Actionable advice:
Absolutely avoid Green Tea Extract and green tea consumption during treatment with bortezomib.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Taken together, our results indicate that green tea polyphenols may have the potential to negate the therapeutic efficacy of BZM and suggest that consumption of green tea products may be contraindicated during cancer therapy with BZM.
Label source:
PubMed: Green tea polyphenols block the anticancer effects of bortezomib and other boronic acid-based proteasome inhibitors. (PMID 19190249)
Action type:
avoid
Target id:
/intervention/nadolol
Target name:
Nadolol
Severity:
major
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green tea catechins inhibit the OATP1A2 transporter in the intestine, which is responsible for absorbing the beta-blocker nadolol, leading to significantly lower blood levels and reduced effectiveness.
Actionable advice:
Green Tea Extract should be avoided while prescribed nadolol.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
Organic anion-transporting polypeptides (OATPs) are multispecific transporters that mediate the uptake of numerous drugs and xenobiotics into cells. Here, we examined the effect of green tea (Camellia sinensis) catechins on the function of the four OATPs expressed in human enterocytes and hepatocytes.
Label source:
Action type:
avoid
Target id:
/intervention/iron-bisglycinate
Target name:
Iron Supplements
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
2
Hours after target:
2
Description:
Polyphenols (tannins and catechins) in green tea bind to non-heme iron in the gut, forming insoluble complexes that prevent its absorption.
Actionable advice:
Green Tea Extract and iron supplements should be separated by at least 2 hours.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
A cup of coffee reduced iron absorption from a hamburger meal by 39% as compared to a 64% decrease with tea, which is known to be a potent inhibitor of iron absorption.
Label source:
PubMed: Inhibition of food iron absorption by coffee. (PMID 6402915)
Action type:
separate
Target id:
/dietary/meal
Target name:
Any Caloric Meal
Severity:
major
Interaction type:
requirement
Nature:
temporal
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Consuming Green Tea Extract with food slows the absorption of catechins, reducing peak plasma concentrations and mitigating the risk of liver toxicity associated with high doses.
Actionable advice:
Green Tea Extract should be taken at the same time as a meal.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Based on these findings, USP included a cautionary labeling requirement in its Powdered Decaffeinated Green Tea Extract monograph that reads as follows: "Do not take on an empty stomach.
Label source:
PubMed: United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts. (PMID 32140423)
Action type:
informational_none
Target id:
/class/anticoagulants-antiplatelets
Target name:
Anticoagulants and Antiplatelets
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green tea contains vitamin K, which can counteract the effects of warfarin. Additionally, catechins may have antiplatelet properties, potentially increasing bleeding risk when combined with other anticoagulants or antiplatelets.
Actionable advice:
It is important to talk to a doctor before use while taking blood-thinning medications, as dose adjustments may be necessary.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Some botanicals may cause bleeding events when taken alone (e.g., garlic and Ginkgo biloba) and may have anticoagulant, antiplatelet, and/or fibrinolytic properties.
Label source:
Action type:
adjust_with_prescriber
Target id:
/class/cyp3a4-substrates
Target name:
CYP3A4 Substrates
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green tea catechins can inhibit the CYP3A4 metabolic enzyme, potentially increasing the blood levels and side effects of drugs metabolized by this pathway (e.g., some statins, calcium channel blockers).
Actionable advice:
This is best used with caution, and it is important to talk to a pharmacist when taking medications metabolized by CYP3A4.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Blood pressure should be closely
monitored when Amlodipine is co-administered with CYP3A4 inducers.
Label source:
Action type:
informational_none
Target id:
/class/cyp1a2-substrates
Target name:
CYP1A2 Substrates
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green tea catechins can inhibit the CYP1A2 enzyme, which may increase the concentration and risk of toxicity from drugs like theophylline or clozapine.
Actionable advice:
It is worth watching out for side effects, and it is important to talk to a doctor if taking medications metabolized by CYP1A2.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
The ingestion of beverages containing large amounts of green tea catechins together with drugs that are metabolized by CYP1A2, CYP2C9, and CYP3A4 should be avoided.
Label source:
PubMed: Inhibitory Effects of Eight Green Tea Catechins on Cytochrome P450 1A2, 2C9, 2D6, and 3A4 Activities. (PMID 27518169)
Action type:
monitor
Target id:
/intervention/folate
Target name:
Folate (Vitamin B9)
Severity:
moderate
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
High concentrations of green tea catechins can inhibit dihydrofolate reductase (DHFR), an enzyme essential for folate metabolism, potentially reducing the bioavailability and function of folic acid.
Actionable advice:
It is a good idea to maintain adequate folate intake and to consider separating doses if taking high-dose Green Tea Extract.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Using an in vitro enzyme activity assay, we observed a time- and dose-dependent inhibition of DHFR activity by epigallocatechin gallate and a green tea extract.
Label source:
PubMed: Greeen tea extracts lower serum folates in rats at very high dietary concentrations only and do not affect plasma folates in a human pilot study. (PMID 19826188)
Action type:
informational_none
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green Tea Extract contains caffeine and may interfere with folate metabolism, both of which are concerns during pregnancy. High doses should be avoided.
Actionable advice:
High-dose Green Tea Extract is best avoided during pregnancy, and it is important to talk to a doctor about moderate intake.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
Also, green tea might increase the risk of birth defects associated with folic acid deficiency.
Label source:
Anecdotal: WebMD
Action type:
avoid
Target id:
/condition/iron-deficiency-anemia
Target name:
Iron-Deficiency Anemia
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
The catechins in Green Tea Extract strongly inhibit the absorption of non-heme iron, which can worsen iron-deficiency anemia or make it more difficult to treat.
Actionable advice:
Green Tea Extract is best avoided with iron-deficiency anemia, or used with extreme caution far from meals.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
Tea interferes with iron absorption and can lead to iron deficiency anemia when consumed in large quantities.
Label source:
Primary literature: https://pmc.ncbi.nlm.nih.gov/articles/PMC5093162/
Action type:
avoid
Target id:
/dietary/iron-rich-foods
Target name:
Iron-Rich Foods
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
1
Hours after target:
1
Description:
The tannins in green tea bind to non-heme iron found in plant-based foods, significantly reducing its absorption from a meal.
Actionable advice:
Green Tea Extract is best avoided with iron-rich meals, especially with a risk for iron deficiency.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
with the inhibitory effects predominantly facilitated by the marked iron-binding properties of the phenolic compounds bearing catechol groups in tea
Label source:
Primary literature: https://pmc.ncbi.nlm.nih.gov/articles/PMC5093162/
Action type:
avoid
Target id:
/circadian/sleep
Target name:
Going to Sleep
Severity:
moderate
Interaction type:
adverse
Nature:
temporal
Temporal spacing:
Hours before target:
8
Hours after target:
null
Description:
The caffeine in most Green Tea Extracts is a stimulant that can interfere with sleep onset and quality if taken too close to bedtime.
Actionable advice:
Green Tea Extract is best taken more than 8 hours before intended bedtime.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Caffeine consumption reduced total sleep time by 45 min and sleep efficiency by 7%, with an increase in sleep onset latency of 9 min and wake after sleep onset of 12 min.
Label source:
PubMed: Sleep medicine reviews (2023)
Source url:
Exact phrase from label:
However, caffeine in green tea can interfere with sleep.
Label source:
PubMed: Journal of clinical biochemistry and nutrition (2017)
Source url:
Exact phrase from label:
Treatment with GT (1500 mg/kg) significantly elevated the sleep latency and wakefulness throughout the treatment period, and chronic administration of GT consistently maintained an increase in wakefulness for up to 3 h.
Label source:
PubMed: Nutrients (2023)
Action type:
separate
Target id:
/class/stimulants
Target name:
Stimulant Medications
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green Tea Extract contains caffeine and has its own mild stimulant properties, which can add to the effects of other stimulants, increasing the risk of anxiety, rapid heart rate, and high blood pressure.
Actionable advice:
Caution is a good idea when combining with other stimulants, and it is worth monitoring for symptoms like jitteriness or palpitations.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Tea (Camellia sinensis) is prized for its polyphenols, which dictate flavor and confer health benefits, yet its inherent caffeine content poses health risks to vulnerable populations.
Label source:
PubMed: Synthesis and Evaluation of Mordenite Zeolite (MOR Zeolite) for Selective Caffeine Adsorption From Green Tea Extract. (PMID 41204434)
Action type:
monitor
Target id:
/class/ugt1a1-substrates
Target name:
UGT1A1 Substrates
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
EGCG in green tea extract can inhibit the UGT1A1 enzyme, potentially increasing the toxicity of certain chemotherapy drugs like irinotecan.
Actionable advice:
Green Tea Extract is best avoided during chemotherapy with drugs metabolized by UGT1A1.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
The study reveals that catechins significantly inhibit UGT1A1-dependent glucuronidation and CYP3A4-mediated oxidation of irinotecan, with over 35% inhibition observed at 10 µM concentrations.
Label source:
Primary literature: https://www.academia.edu/16444469/Green_tea_and_irinotecan_metabolism
Action type:
avoid
Target id:
/biomarker/alanine-aminotransferase
Target name:
Alanine Aminotransferase (ALT)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
High-dose Green Tea Extract supplementation can cause idiosyncratic liver injury, leading to clinically significant elevations in liver enzymes like ALT, which can confound diagnostic testing.
Actionable advice:
Use should be discontinued, and it is important to let a doctor know, if symptoms of liver distress or elevated liver enzymes occur.
Validation status:
validated_via_clinical_guidance
Evidence tier:
tier_b
Evidence basis:
clinical_guidance_verbatim
Evidence anchors:
Exact phrase from label:
Green tea extract (GTE) was associated with ALT elevations in 6.7% of patients compared to 0.7% of controls.
Label source:
Clinical guidance: NIH LiverTox — Green Tea Extract hepatotoxicity
Action type:
avoid
Target id:
/class/p-glycoprotein-substrates
Target name:
P-glycoprotein Substrates
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green tea catechins may inhibit the P-glycoprotein efflux pump, which could slightly increase the absorption and concentration of certain drugs like digoxin.
Actionable advice:
This is best used with caution, and it is worth monitoring for side effects when taking P-glycoprotein substrate medications.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Therefore, drugs that induce/inhibit P-glycoprotein have the potential to alter digoxin
pharmacokinetics.
Label source:
Action type:
monitor
Target id:
/condition/anxiety-disorder
Target name:
Anxiety Disorders
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
The caffeine content in Green Tea Extract can exacerbate symptoms of anxiety, such as nervousness, palpitations, and restlessness in susceptible individuals.
Actionable advice:
Decaffeinated versions, or very low starting doses, are generally best in the presence of an anxiety disorder.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Chronic, heavy caffeine ingestion may cause or exacerbate anxiety and may be associated with depression and increased use of antianxiety drugs. Caffeine may cause anxiety and panic in panic disorder patients and may aggravate the symptoms of premenstrual syndrome.
Label source:
PubMed: American family physician (1988)
Source url:
Exact phrase from label:
Caffeine can induce anxiety, exacerbate psychotic symptoms in some patients with schizophrenia and cause insomnia.
Label source:
PubMed: International journal of psychiatry in clinical practice (2001)
Source url:
Exact phrase from label:
Among the responders, 98% of them replied they had symptoms that could be caused by caffeine, in order of palpitations (47.4%), frequent urination (42.9%), anxiety (27.1%), indigestion (17.5%), and excitement (17.5%).
Label source:
PubMed: Korean journal of medical education (2024)
Action type:
informational_none
Target id:
/intervention/caffeine
Target name:
Caffeine
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Green Tea Extract naturally contains caffeine, and taking it with other caffeine sources will have an additive effect, potentially leading to overstimulation, anxiety, or sleep disruption.
Actionable advice:
Account for the caffeine in your extract when calculating your total daily caffeine intake.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Green tea extract has high natural caffeine content, with potential for additional polyphenol-related health benefits.
Label source:
PubMed: Supplementation of green tea extract on early-life behavior, health, and growth of Holstein heifer calves. (PMID 41850366)
Action type:
informational_none