PRACTICAL GLP-1 SUPPORT
GLP-1 side effects: common does not mean ignore everything
Nausea, vomiting, diarrhoea and constipation are commonly reported with GLP-1 and related weight-management medicines. Some symptoms improve as the body adjusts; severe, persistent or worsening symptoms need advice. Social-media remedies are not a substitute for the treating service.
Quick takeaways
- Follow the prescribed dose schedule.
- Hydration and adequate intake matter.
- Do not copy somebody else's medication or side-effect remedy.
- Severe abdominal pain, repeated vomiting or dehydration need prompt help.
The bits blokes actually talk about
The official side-effect lists matter, but real life is usually less tidy. Matt’s own experience included nausea, stomach cramps and the dreaded “eggy breath”. For him those difficult bits settled, but that is one person’s experience — not a prediction of what will happen to you.
If something is new, severe, persistent or getting worse, treat it as information for the service looking after your prescription rather than something you have to “push through”.
Eggy breath: what actually helps
Those sulphur-smelling burps can be grim. A slowed-down stomach can make rich meals sit around longer, so the boring fixes are often the useful ones: eat smaller portions, eat more slowly, keep fluids going, and notice whether very fatty or heavy meals make it worse. Staying upright after eating can also be easier than flopping straight onto the sofa.
Do not try to “tough it out” if the burps arrive with repeated vomiting, severe or persistent tummy pain, a swollen abdomen, or you cannot keep fluids down. Those are reasons to contact the service looking after your medicine or seek urgent medical help depending on severity.
This is practical symptom support, not a diagnosis. If it keeps happening or is getting worse, tell your prescriber or pharmacist rather than endlessly changing food around it.
Nausea and reduced appetite
Smaller meals, slower eating and avoiding foods that clearly worsen symptoms may help some people. The aim is not to stop eating altogether. Regular inability to meet fluid or nutrition needs should be discussed with the treating service.
Symptoms after a dose change are useful information for the prescriber; they are not a challenge to endure silently.
Constipation
Lower food intake, less fibre, dehydration and reduced movement can contribute. Fluids, appropriate fibre and activity may help, but advice must account for the individual and their other conditions or medicines.
Persistent constipation, significant pain, vomiting or inability to pass stool or wind needs medical advice.
Vomiting and diarrhoea
Repeated vomiting or diarrhoea can cause dehydration. Follow sick-day advice relevant to your health and medicines, and contact the treating service where symptoms persist.
Do not take extra doses after vomiting or alter the schedule without instructions.
Fluids, salts and electrolytes
Keep drinking regularly. If you feel sick, small sips may be easier. Vomiting or diarrhoea can cause you to lose water and salts (electrolytes). Ask a pharmacist whether an oral rehydration solution is appropriate for you, especially if you have other conditions or take other medicines. There is no general requirement to take an electrolyte supplement after every injection.
If you cannot keep fluids down, are passing much less urine, or dizziness when standing does not go away, get urgent medical advice. Severe, persistent stomach pain that may spread to your back, with or without sickness, needs urgent medical help because it can be a sign of pancreatitis. Do not wait for a company inbox.
Follow the current leaflet for your medicine and your clinical team’s advice. NHS: dehydration and oral rehydration · MHRA: medicine risks and when to get help. Guidance checked 2 October 2026.
Missed dose, changed day or not sure what to do?
There is not one universal GLP-1 missed-dose rule, so do not guess and do not double up.
- Mounjaro (tirzepatide) weekly injection: the UK leaflet says take the missed dose as soon as possible if it is 4 days or less late. If more than 4 days have passed, skip it and use the next dose on your usual day. Leave at least 3 days between doses.
- Wegovy (semaglutide) weekly injection: the UK leaflet says take it as soon as possible if it is 5 days or less late. If more than 5 days have passed, skip it and continue on the usual day.
- Wegovy tablets: if you forget a dose, skip it and take your normal dose the next day.
Never take a double dose to make up for one you missed. The current leaflet for the exact product in your hand—and your prescriber or pharmacist—wins if anything here differs from your own instructions.
Shift can help you organise food, fluids, movement and what to remember; it does not replace prescribing advice.
Red flags
Seek urgent medical help for severe or persistent abdominal pain, signs of serious dehydration, collapse, breathing difficulty, swelling suggesting an allergic reaction, or rapidly worsening symptoms.
This page cannot determine whether a symptom is caused by the medicine.
Frequently asked questions
Is nausea normal on GLP-1 treatment?
It is commonly reported, especially around dose escalation, but persistent, severe or worsening nausea should be discussed with the treating service.
What helps constipation on GLP-1 medication?
Fluids, suitable fibre and movement may help some people, but persistent or concerning symptoms require individual advice.
Sources you can inspect
These sources support general information. They do not determine individual diagnosis, eligibility or treatment.
Sort the practical bit
If food is the problem today, use Grub to work with what you can actually manage. For medicine, dose or persistent/worrying symptoms, use your prescriber or appropriate NHS help.