GLP-1 weight-loss injections and blood pressure tablets: what to record over the weeks
Taking weight-loss injections and blood pressure tablets? How to log your readings over weeks and what to bring to your doctor.
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You take blood pressure tablets. You are on a weight-loss injection such as Wegovy or Mounjaro (Zepbound in the US), or about to start one. You probably wonder what will happen to your blood pressure and whether you still need the tablets. Readings, intake and dizziness can go on paper or into Sam: the blood pressure diary and the symptom diary. Sam reads Apple Health, so values your monitor stores there come in, and your weight sits in the same app.
Short answer: in the Wegovy weight-management studies, systolic blood pressure fell a few mmHg more than on placebo on average, and the labels also list dizziness and low blood pressure. These are group averages, not a promise for you. Whether your tablets change is your doctor's decision, so keep a dated log and bring it.
This text does not advise you to change, reduce or stop any medicine. That is your doctor's decision alone. Here is what the prescribing information and UK/US guidance say about blood pressure while you lose weight.
What do the prescribing texts say about blood pressure and dizziness?
The US prescribing information for Wegovy lists low blood pressure and dizziness as reported reactions. In the Wegovy weight-management trials, dizziness was reported by about 8% of people on the medicine. On placebo it was around 3% to 4%. The label also notes that low blood pressure, including on standing, was seen more often in people already on blood pressure treatment. All three labels note a small average rise in heart rate, a few beats per minute. Nausea, vomiting and diarrhea can cause fluid loss, so the labels carry a caution about dehydration. Keep drinking, and raise any concern with your care team.
Why does weight loss change the conversation?
Body weight affects blood pressure. The NHS lists losing weight, if you are overweight, among the lifestyle changes that can lower blood pressure. In the Wegovy weight-management studies in the prescribing information, systolic blood pressure fell a few mmHg more than placebo on average. The difference was in the region of 3 to 5 mmHg. These are group averages, not a promise for you. Whether any dose needs to change is your doctor's decision, not one you make at home.
Who decides about your tablets?
Your doctor does. Changes to blood pressure medicine are the prescriber's decision. That holds even when you have lost weight and feel great. Blood Pressure UK is explicit: do not stop your medicines just because your home reading has fallen, and talk to your doctor first. Do not stop the injection on your own either, without talking to your prescriber. Bring the numbers, and let the practice decide.
How do you measure while the dose changes?
Home measurement follows a routine that the American Heart Association and Blood Pressure UK describe. Use a validated upper-arm cuff, not a wrist or watch device. Sit quietly for about five minutes, put your feet flat, and support your arm at heart level. The AHA says to take two readings one minute apart; Blood Pressure UK says three readings, one to two minutes apart. Both describe morning and evening readings over a week, and Blood Pressure UK suggests measuring more often after a new medicine or a higher dose. Whether such a week fits around a new dose step is agreed with your team. In the UK the NHS counts a home reading of 135/85 or higher as high, while US guidelines often use a lower target of 130/80, so ask your practice which number applies to you.
Which notes go alongside the readings?
Start the page with your monitor, the arm, your tablets and their times. Add the injection product, the step from your prescription, the injection day and the date of the last step. Then, for each reading, add the pulse. Add dizziness yes or no, with the time and whether it was on standing. Add vomiting or diarrhea that day, roughly how much you drank, and your weight on the same scale at the same time of day. Your tablet intake can be ticked off in your medication list in Sam. For the wider picture, see daily readings while living with high blood pressure.
When do you call the practice, and when the emergency number?
This is general information, not a diagnosis. Use your local emergency number (112 in the EU, 999 in the UK, 911 in the US) for chest pain or tightness, shortness of breath, confusion, or signs of stroke. After a faint, call the emergency number if you are not clear within about a minute. Call it too if you injured yourself, you have chest pain, shortness of breath or a racing heart, or you fainted while exercising or lying down. If you recover quickly, call your practice the same day. Call your practice and do not wait for the next visit if dizziness keeps happening, your readings are clearly lower than usual and you feel weak or lightheaded, or vomiting or diarrhea continues. Sam does not decide what is urgent.
What do you bring to the appointment?
Bring your blood pressure log for the measuring week. Bring your medicine list with times, and the prescription or the box of the injection. Bring your monitor too, so the practice can compare it with theirs. Useful questions: how long should I keep measuring, from which values or symptoms should I get in touch, and when will we look at the tablets again. How the numbers are read is the practice's call. If you are new to this, see new to a high blood pressure diagnosis.
Log your blood pressure during the weight-loss weeks in Sam and take it to your appointment
You take a dated course of readings, intake and how you feel to the visit, instead of remembering single weeks. The high blood pressure program in Sam is a diary with a doctor report and a monthly questionnaire.
- Instead of paper or a notes app: you enter readings and intake, and if your monitor stores values in Apple Health, Sam brings them in.
- Instead of screenshots: the doctor report is a PDF for a period you choose, and weight, sleep and resting heart rate sit beside it.
- Instead of memory: dizziness goes into the symptom diary for that day.
- You log each reading with date, time, pulse and arm.
- Sam does not measure blood pressure and gives no dosing advice. Whether a medicine starts, stops or changes is your doctor's decision.
Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any condition or health state. Always consult qualified professionals for medical decisions.
Related reading
- New to a high blood pressure diagnosis
- Living with high blood pressure: daily readings
- Blood pressure log: print or app
- Weight-loss medication and heartburn: what to log
- Blood Pressure in Pregnancy: Home Monitoring
Sources
Updated: October 2026
- FDA: Wegovy (semaglutide) Prescribing Information, Novo Nordisk label
- FDA: Ozempic (semaglutide) Prescribing Information, Novo Nordisk label
- Eli Lilly: Mounjaro (tirzepatide) Prescribing Information
- American Heart Association: Home blood pressure monitoring
- Blood Pressure UK: How to measure your blood pressure at home
- NHS: Blood pressure test
- NHS: High blood pressure (hypertension): prevention
More on High Blood Pressure
Frequently Asked Questions
Does a weight-loss injection lower blood pressure?+
Body weight affects blood pressure, and the NHS lists losing weight, if you are overweight, among the changes that can lower it. In the Wegovy weight-management studies in the prescribing information, systolic blood pressure fell a few mmHg more than placebo on average. These are group averages, not a promise for you, and what your own values do is for your doctor to say.
Can I stop my blood pressure tablets if my reading falls?+
Not on your own: Blood Pressure UK says do not stop your medicines just because your home reading has fallen, and to talk to your doctor first. Whether a tablet starts, stops or changes is your doctor's decision. Sam gives no dosing advice.
Can these medicines cause dizziness?+
Yes. In the Wegovy weight-management trials, dizziness was reported by about 8% of people on the medicine versus around 3% to 4% on placebo, and low blood pressure or dizziness on standing was also reported. If dizziness keeps happening, tell your practice.
How often should I measure my blood pressure while on the medicine?+
When you start treatment or change it, it can help to measure more often, as Blood Pressure UK describes, for example morning and evening for a week. The AHA says to take two readings one minute apart; Blood Pressure UK says three, one to two minutes apart. Whether a measuring week fits around a new dose step is something you agree with your practice.
Can an Apple Watch measure my blood pressure?+
No, the American Heart Association recommends a validated upper-arm cuff monitor for a reliable home reading, not a wrist or watch device. Sam does not measure blood pressure. You enter the values from your monitor, or Sam reads them if your monitor stores them in Apple Health.
Why do I occasionally feel dizzy when I stand up?+
The prescribing information for these medicines lists low blood pressure or dizziness on standing among the reported reactions. Note the date, time and situation, and mention it to your practice. If you faint and do not recover quickly, use your local emergency number (112 in the EU, 999 in the UK, 911 in the US).
Do the labels say anything about my blood pressure tablets?+
The prescribing information gives no instruction about blood pressure tablets. Changes to your tablets are your doctor's decision, even while you lose weight. Bring a dated home log and let the practice read the numbers.