Based on PubMed | Does drinking green tea lower blood pressure in people with hypertension?

Drinking green tea appears to have a small blood pressure–lowering effect, but it should be viewed as a modest add‑on to standard care rather than a primary treatment for hypertension. Across randomized trials and meta‑analyses, average reductions are roughly 2 mmHg in both systolic (top number) and diastolic (bottom number) readings, which is helpful but limited in size. ^{[1] [2]}

What the evidence shows

• Meta-analyses of randomized controlled trials: Pooled data from 13 trials (1,367 participants) found that green tea lowered systolic blood pressure (SBP) by about 1.98 mmHg and diastolic blood pressure (DBP) by about 1.92 mmHg compared with control. ^[1] In subgroup analyses, benefits were clearer when caffeine’s effects were minimized, doses of tea polyphenols were moderate, and interventions were longer in duration. ^[1]
• Additional systematic review: A broader review of 20 RCTs (1,536 participants) similarly found a significant reduction in SBP favoring green tea, while also noting improvements in total and LDL cholesterol; however, the blood pressure effect size remained small. ^[2]

How green tea might help

• Vascular and hormonal pathways: Green tea catechins especially EGCG (epigallocatechin gallate) are thought to improve endothelial function and reduce oxidative stress and inflammation, mechanisms linked to better blood vessel relaxation. ^[3] There is also evidence that certain catechin variants may mildly inhibit angiotensin‑converting enzyme (ACE), a key regulator of blood pressure, which could contribute to small BP reductions in some tea types. ^{[4] [5]}

Practical expectations

• Magnitude of effect: A ~2/2 mmHg average reduction is meaningful at a population level but modest for an individual. ^{[1] [2]} It should not replace guideline‑recommended lifestyle measures (like the DASH diet, salt reduction, weight management, and exercise) or prescribed medications when needed. ^[6]
• Time frame and dose: Studies suggest more consistent effects with longer-term use and moderate catechin doses; very high doses have not shown better blood pressure results and may pose safety concerns. ^{[1] [2]}

Safety and interactions

• Caffeine considerations: Caffeinated green tea can transiently raise heart rate or cause jitteriness in sensitive people, and subgroup findings suggest that minimizing caffeine helps clarify blood pressure benefits. ^[1]
• Drug interactions: Green tea (and especially concentrated extracts) can affect drug absorption and metabolism. For example, it can reduce absorption of nadolol (a beta‑blocker) by inhibiting the intestinal transporter OATP1A2, leading to lower blood levels and reduced effect. At least one clinical scenario and a case report described lower nadolol concentrations and relapse of arrhythmia with green tea intake. ^{[7] [8] [9]}
• Liver safety with extracts: Drinking green tea as a beverage is generally well tolerated, but high‑dose extracts (not typical brewed tea) have been linked to elevated liver enzymes and rare hepatotoxicity; risk appears higher with fasting and large EGCG doses. ^{[10] [11]}
• Anticoagulants: Very large daily amounts of brewed green tea (about 0.5–1 gallon/day) may supply enough vitamin K to potentially interfere with blood thinners like warfarin, though this is more theoretical and depends on total intake. ^[12]

How to include green tea safely

• Reasonable intake: For most adults with hypertension, 1–3 cups of brewed green tea per day is a sensible, moderate range that aligns with the doses commonly studied and balances potential benefits with tolerability. This level also avoids the higher catechin loads associated with some extracts that may affect liver enzymes. ^{[13] [11]}
• Be consistent with medications: If you take beta‑blockers such as nadolol, discuss green tea use with your clinician and monitor blood pressure and heart rate when starting or changing intake, since green tea can lower nadolol absorption and effectiveness. ^{[7] [9]}
• Lifestyle first-line: Continue evidence‑based measures like the DASH eating pattern, reduced sodium, regular physical activity, weight control, limited alcohol, and not smoking, as these have substantially larger effects on blood pressure than green tea alone. ^[6]

---

Bottom line

• Green tea can modestly lower blood pressure on the order of ~2 mmHg systolic and diastolic based on randomized trials and meta‑analyses. ^{[1] [2]}
• Use it as a supportive habit, not a substitute for proven lifestyle strategies and prescribed medications. ^[6]
• If you take certain heart medicines (notably nadolol), check for interactions and monitor closely. ^{[7] [8] [9]}

---

Quick reference table

Topic	Key takeaways
Effect size	Average ~−2 mmHg SBP and ~−2 mmHg DBP vs. control; greater consistency with longer use and moderate catechin doses. [1] [2]
Mechanisms	Endothelial support, antioxidant/anti‑inflammatory effects, possible mild ACE inhibition with specific catechins. [3] [4] [5]
Best use	As an adjunct to standard lifestyle and medications; not a standalone treatment for hypertension. [6]
Safety	Brewed tea generally safe; high‑dose extracts linked to liver enzyme elevations and rare hepatotoxicity. [10] [11]
Interactions	May reduce absorption/effect of nadolol via OATP1A2 inhibition; discuss with your clinician. [7] [9]

If you’d like, I can help tailor a safe daily plan for green tea that fits with your current medications and blood pressure goals.