Green tea catechins and how the body handles medicines
What it found
In most clinical studies, drinking green tea lowered the amount of certain medicines that reached the bloodstream, in some cases by 18 to 99 percent.
A smaller share of analyses found no change, and one found a 50 percent rise.
What they found
Studies in people
Most medicines dropped
Most analyses, 72 percent, found the amount of medicine reaching the bloodstream fell when green tea was consumed. The falls ranged from 18 to 99 percent. Medicines included atorvastatin, celiprolol, digoxin, fexofenadine, folic acid, lisinopril, nadolol, nintedanib, raloxifene and rosuvastatin.
One medicine rose
One analysis, 6 percent, found a 50 percent rise in the amount of sildenafil reaching the bloodstream with green tea.
Some medicines unchanged
For 22 percent of analyses, green tea did not change how the body handled the medicine. These included fluvastatin, pseudoephedrine, simvastatin and tamoxifen.
Case reports on effects
Case reports have linked changes in how the body handles a medicine after green tea consumption to changes in how well the medicine works or its safety. Examples given are nadolol and erlotinib.
Other findings
How the drop may happen
For most medicines where an interaction was seen, the authors suggest green tea catechins lower how much medicine is taken up from the gut. They propose this happens by blocking OATP uptake, especially OATP1A2, boosting P-gp efflux activity, or making the medicine less soluble.
What the authors conclude
“These findings prompt the need for further research in relating evidence from existing literature to predict additional clinically important green tea-drug interactions and to provide appropriate recommendations for patients and clinicians.”
Also in their conclusions
- They say these findings show more research is needed to link what is already known to predict other green tea-drug interactions that matter in practice.
- They want this to help provide suitable advice for patients and clinicians.
How it was done
People often take green tea or green tea supplements alongside their medicines without knowing it might change how those medicines work. The authors wanted to pull together what is known about these interactions.
They reviewed clinical studies that looked at whether green tea catechins change the way the body handles medicines used in medical care.
What it can’t tell you
- We summarised it from the abstract only.
- This is a summary of other studies, so it cannot prove that green tea itself causes any particular change in a medicine's effect.
- It cannot say how green tea might interact with medicines not included in the reviewed studies.
Who paid
- Authors work at
- University of Sydney, Australia
The paper
- Title
- Green Tea Catechins as Perpetrators of Drug Pharmacokinetic Interactions
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Kyriacou NM, Gross AS, McLachlan AJ (2025). Green Tea Catechins as Perpetrators of Drug Pharmacokinetic Interactions. Clinical pharmacology and therapeutics. doi:10.1002/cpt.3547PubMed 39748104DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error