GLP-1s and Blood Pressure: Trial Results and Safety

What the Clinical Trials Show

Systolic blood pressure is the top number; diastolic is the bottom number.[4] When reading trial results, distinguish a change from the participant's starting pressure from the difference compared with placebo. Both groups may improve, so these are not the same number.

STEP 5 — Semaglutide for Weight Management

STEP 5 enrolled 304 adults with obesity, or overweight with at least one weight-related condition, without diabetes. It compared once-weekly semaglutide 2.4 mg—a GLP-1 medication regimen—with placebo, both alongside behavioral support, over 104 weeks.[3]

Average systolic pressure fell 5.7 mmHg with semaglutide and 1.6 mmHg with placebo. The study's estimated treatment difference was 4.2 mmHg lower with semaglutide (95% confidence interval 1.0–7.3 mmHg lower). This was a confirmatory secondary endpoint; the trial's primary endpoints concerned weight loss.[3]

The estimated difference is reported as published, rather than recalculated from the rounded group changes. These findings describe the studied semaglutide regimen, not an identical effect for every Ozempic (semaglutide) dose or other formulation.[3]

SURMOUNT-1 — Tirzepatide for Weight Management

A published post hoc analysis of SURMOUNT-1 examined blood pressure in adults with obesity or overweight and a weight-related complication, without diabetes. Tirzepatide 5 mg, 10 mg or 15 mg was compared with placebo alongside lifestyle intervention over 72 weeks. People with systolic pressure of at least 160 mmHg or diastolic pressure of at least 100 mmHg at screening were excluded.[2]

With tirzepatide doses pooled, average systolic pressure fell 8.1 mmHg versus 1.3 mmHg with placebo, an estimated 6.8 mmHg greater reduction (95% confidence interval 5.7–7.9 mmHg). The estimated placebo-adjusted diastolic reduction was 4.2 mmHg. These are office blood pressure results from an analysis using data during treatment, excluding data after study-drug discontinuation.[2]

SURMOUNT is the weight-management program; SURPASS studied tirzepatide in type 2 diabetes. Do not relabel SURMOUNT-1 results as SURPASS data or compare these results with STEP 5 as though the two drugs were tested against each other.[2][3]

LEADER — Liraglutide in Type 2 Diabetes

LEADER enrolled 9,340 people with type 2 diabetes at high cardiovascular risk. At 36 months, systolic pressure was 1.2 mmHg lower with liraglutide than placebo, while diastolic pressure was 0.6 mmHg higher. Heart rate was 3.0 beats per minute higher, not lower.[1]

LEADER also found a 13% relative reduction in its combined endpoint of cardiovascular death, nonfatal heart attack or nonfatal stroke (hazard ratio 0.87). That is not a 13% reduction in cardiovascular death alone, and the trial did not establish that blood pressure lowering caused the cardiovascular benefit.[1]

Trial doses describe the research, not instructions for treatment. Your prescriber determines your actual medication and dose. Do not adjust your dose without consulting them.

Dose and Timing: What the Numbers Cannot Tell You

A higher dose does not guarantee a larger blood pressure reduction. In the SURMOUNT-1 analysis, blood pressure reductions were broadly similar across doses, and the highest dose did not consistently produce the largest change.[2]

Average blood pressure declined over the first 24 weeks in that analysis and then largely stabilized through week 72.[2] This is not a universal onset schedule. It does not support a promise of a change within two to four weeks or a fixed date when every patient's readings will stabilize.

Do not increase a GLP-1 dose to chase a blood pressure reading, and do not wait for a trial milestone to report symptoms. The decision to change either medication belongs with your prescriber.

Why Blood Pressure May Fall

Weight loss appears to explain much of the effect. The SURMOUNT-1 investigators' post hoc statistical mediation analysis estimated that weight change accounted for 67.6% of the systolic and 71.0% of the diastolic reduction seen with tirzepatide, while also finding an effect not explained by weight change.[2]

That analysis does not establish that the remaining effect comes directly from one kidney or blood-vessel pathway. Human mechanistic studies support possible effects on sodium excretion under volume-expanded conditions, angiotensin II and kidney perfusion, but the findings do not prove why blood pressure falls during long-term treatment.[10] Evidence for improved endothelial function is also limited: a small meta-analysis found no statistically significant improvement in flow-mediated dilation with GLP-1 receptor agonists.[11]

Blood pressure is also distinct from a cardiovascular outcome. A study showing lower readings is not, by itself, a study showing fewer heart attacks or strokes. For the separate outcomes evidence, see GLP-1s and heart health.

Low Blood Pressure, Dizziness and Dehydration

Low blood pressure can cause dizziness, lightheadedness or fainting. Symptoms after standing or changing position may indicate postural (orthostatic) hypotension; a clinician can assess whether that explains your symptoms.[7][8]

Zepbound's current prescribing information reports hypotension in 1.6% of treated adults versus 0.1% with placebo in a pool of two weight-reduction trials. Among Zepbound-treated participants, hypotension was reported in 2.2% of those using antihypertensive medication versus 1.2% of those who were not. Cases also occurred with gastrointestinal adverse effects and dehydration.[6] These label figures apply to tirzepatide in those trials, not automatically to semaglutide or every GLP-1-based medicine.

Vomiting and diarrhea can cause dehydration, and Wegovy's current prescribing information warns about acute kidney injury due to volume depletion and advises renal-function monitoring when adverse reactions could cause volume depletion.[5] Contact your care team if symptoms persist or you cannot keep fluids down. Fluid needs may be individualized, especially if you have kidney disease or have been given a fluid restriction. Do not self-treat with electrolyte packets or added potassium unless your clinician says they are appropriate for you.

Get up slowly and avoid sudden changes of position if you have symptoms of low blood pressure.[8] Seek medical advice for dizziness or lightheadedness and prompt medical attention for fainting. Do not rely on a home reading to rule out a serious problem.[7][8]

Taking GLP-1s With Blood Pressure Medicines

Bring a complete medication list to your prescriber, including ACE inhibitors, ARBs, diuretics, beta-blockers and calcium channel blockers if you take them. A medication review should consider your readings, symptoms, fluid intake and the reasons each medicine was prescribed—not an automatic dose-cutting rule.

The Zepbound label reports more hypotension among participants taking antihypertensives, but it does not rank specific blood pressure drug classes by interaction risk.[6] Weight loss or lower readings alone are not instructions to reduce a diuretic or another medicine.

Blood pressure and heart rate can move in different directions. Wegovy's label describes an increase in resting heart rate, and LEADER also found a higher average heart rate with liraglutide.[1][5] These medicines should not be described as lowering pulse in the same way as beta-blockers. Report a racing heartbeat at rest to your clinician.[5]

Home Monitoring Without a One-Size-Fits-All Schedule

The American Heart Association recommends home monitoring for people with high blood pressure. It does not replace clinician visits or justify stopping medication on your own.[4]

Ask your clinician:

• Whether home monitoring is useful for you and how often to check.
• What your individual target is and which readings should prompt a call.
• Whether a change in symptoms, treatment or weight means the plan needs review.
• Whether readings taken when standing, or a clinician-arranged ambulatory monitor, would help explain symptoms or differences between home and office measurements.

There is no GLP-1-specific home-monitoring schedule established by the trials summarized here or by the 2025 U.S. blood-pressure guideline. That guideline supports home monitoring as part of a standardized treatment plan, while the AHA consumer guidance says to ask your healthcare professional how often to measure.[4][9] A fixed schedule based only on months since the first dose can miss individual needs.

Getting a Useful Reading

The American Heart Association advises using a validated automatic upper-arm monitor and the correct cuff size. Ask your clinician or pharmacist for help choosing one; the AHA links to the US validated device listing. An Amazon search result is not proof that a device has been validated.[4]

For routine seated measurement, the AHA advises:[4]

• Avoid smoking, caffeine and exercise for 30 minutes beforehand; empty your bladder.
• Rest quietly for at least five minutes before measuring.
• Place the cuff on bare skin and support your arm at heart level.
• Take two readings one minute apart and record both.
• Bring your monitor to an appointment to check its accuracy and your technique.

This is measurement technique, not a medication-adjustment protocol. Share the record, including symptoms and when they occurred, rather than deciding on a dose change from one number.

Lifestyle and Follow-Up Still Matter

Continue discussing food choices, sodium intake, physical activity, alcohol and smoking with your care team. Your blood pressure plan should account for other conditions and what is safe and practical for you. The trial benefits were measured alongside behavioral support or usual medical care, not instead of them.[1][2][3]

For people starting treatment, our GLP-1 starter guide provides related patient information. Our cholesterol article discusses another cardiovascular risk factor.

When to Contact Your Care Team

• Readings repeatedly differ from your usual range or the target your clinician gave you.
• You experience dizziness, lightheadedness, a racing heartbeat at rest or fainting.
• Vomiting, diarrhea or trouble drinking raises concern about dehydration.
• You want to discuss a blood pressure medication change, or readings remain above target despite treatment.

For a reading with systolic pressure above 180 or diastolic pressure above 120 mmHg, the AHA advises repeating it after at least one minute and contacting a healthcare professional immediately if it remains very high. If accompanied by chest pain, shortness of breath, weakness, numbness, vision changes or difficulty speaking, call 911. Do not wait for the pressure to fall on its own.[4]

Frequently Asked Questions

How much can GLP-1 medications lower blood pressure?

Results depend on the drug, population, comparator and follow-up. In STEP 5, semaglutide's estimated systolic reduction was 4.2 mmHg greater than placebo at 104 weeks.[3] In a SURMOUNT-1 analysis, pooled tirzepatide doses lowered systolic pressure 6.8 mmHg more than placebo at 72 weeks.[2] These are trial averages, not a prediction or a head-to-head comparison.

Should I stop my blood pressure medication if I start a GLP-1?

No. Do not stop or reduce blood pressure medication without your prescriber's guidance.[4] Share your readings, symptoms and medication list so they can decide whether any change is appropriate.

How quickly does blood pressure change after starting a GLP-1?

There is no single reliable timetable for everyone. In the SURMOUNT-1 analysis, average blood pressure declined over the first 24 weeks and then largely stabilized through week 72.[2] Do not wait for a scheduled milestone to report dizziness, fainting or difficulty keeping fluids down.

Can GLP-1s cause blood pressure to drop too low?

It can happen. Zepbound's prescribing information reports hypotension, particularly among people also taking blood pressure medicines, and notes that cases also occurred with gastrointestinal symptoms and dehydration.[6] Report dizziness or lightheadedness, and seek prompt medical attention for fainting.

Do I need a home blood pressure monitor on a GLP-1?

The American Heart Association recommends home monitoring for people with high blood pressure. Ask your clinician whether it is useful for you and how often to check. Choose a validated upper-arm monitor with the correct cuff size; a shopping listing is not proof of validation.[4]

The Bottom Line

GLP-1 and related medicines can lower blood pressure on average, but the size and timing of the effect vary across trials and individuals.[1][2][3] Keep a clinician-directed monitoring plan, report symptoms, and do not adjust blood pressure medicines or GLP-1 doses yourself.

This article is for informational purposes only and does not replace medical advice. Always talk to your healthcare provider about blood pressure management and medication changes.

Sources

• [1] LEADER: Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes (2016)
• [2] SURMOUNT-1 blood pressure analysis (Heart, 2024)
• [3] STEP 5: Two-year effects of semaglutide (Nature Medicine, 2022)
• [4] American Heart Association: Home Blood Pressure Monitoring
• [5] Wegovy US prescribing information
• [6] Zepbound US prescribing information
• [7] American Heart Association: Low Blood Pressure
• [8] NHS: Low blood pressure (hypotension)
• [9] 2025 U.S. guideline for high blood pressure in adults
• [10] Review of randomized human studies of GLP-1 and kidney mechanisms
• [11] Systematic review and meta-analysis of newer diabetes drugs and vascular function