Almost everyone gets something, and almost all of it is digestive. It is worst in the days after starting or stepping up a dose, and for most people it eases within one to two weeks as the body adjusts.
Nausea leads the list, followed by feeling full very quickly, constipation, reflux and sometimes diarrhoea. Fatigue and headache turn up too, often because intake has dropped faster than people realise.
The pattern matters more than the list. These effects arrive in the days after a dose increase and fade as your body adjusts. Something that arrives out of nowhere at a steady dose, weeks in, is worth reporting rather than assuming.
A great deal of it responds to eating differently: smaller portions, more often, protein first, and stopping when full rather than when the plate is empty. The detail sits in Nausea and digestion, Nutrition on a GLP-1 and Dosing and titration.
The pattern
Managing them
Handling common side effects week by week
Expect the first week
The days after your first dose and after each increase are when symptoms bunch up. Knowing that in advance stops people quitting in week one.
Change how you eat
Smaller and more often, protein first, less fat and less at once. This does more for nausea than anything else available.
Hold rather than push
If a dose is not settling, holding it is standard. Almost everyone with a miserable experience went up too fast.
Report what does not fit
Anything severe, anything new at a steady dose, or anything on the red-flag list is a call rather than something to wait out.
Less obvious
The effects people do not expect
Constipation is under-reported and easy to fix if it is mentioned. So is dehydration, which follows naturally when appetite and drinking both drop, and which explains a lot of the headaches and fatigue.
Food aversion is the other one: specific things you used to like becoming unappealing. It is common, it usually settles, and it is worth mentioning because it affects what you can realistically eat. Worth reading next: Serious side effects, Protein and muscle loss and What to expect.
ConstipationUnder-reported
DehydrationEasy to miss
Food aversionUsually settles
Side effects
Other side effect topics
Nausea in detail, the red flags, interactions and mood.
How long they last, whether they mean it is working, and when to worry.
Usually one to two weeks after starting or after a dose increase, then they ease. If something is not easing after that, the dose is generally the thing to adjust rather than a symptom to endure.
Not reliably. Plenty of people lose weight with very little nausea, and plenty feel unwell without much effect. They are separate things, so severity is not a progress measure.
Eating less at once and more often, protein first, and cutting back on fatty or very large meals. Most people find that does more than anything else available to them.
Report it rather than stopping unilaterally. Most of the time holding the dose fixes it. The exception is the red-flag list, where stopping and seeking care the same day is correct.
Often mildly, for a few days after each step. That is expected and is why the schedule spaces increases out rather than moving quickly.
