Your first 90 days on a GLP-1
Week by week: what the starter dose actually feels like, when appetite changes show up, when your provider will titrate, and the three weeks most people find hardest.
Most people start a GLP-1 with a vague expectation that the weight will simply come off. What actually happens is more gradual, more physical, and more manageable than that — provided you know what is coming. Here is the honest version.
Weeks 1–4: the starter dose does almost nothing, on purpose
Your first dose is not a treatment dose. It exists to let your gut adjust. Semaglutide starts at 0.25 mg and tirzepatide at 2.5 mg, and neither is expected to drive meaningful weight loss. If you step on the scale at week three and feel disappointed, you have misunderstood the schedule, not failed at it.
What you will notice is subtler. Meals start feeling larger than they are. You may put your fork down with food still on the plate — an experience some patients find genuinely disorienting the first few times.
The most common mistake in month one is pushing for a faster titration. Going up before your gut has adapted is the single biggest predictor of quitting over side effects.
Weeks 5–8: the first real dose
This is where most people feel the medication properly. Appetite drops noticeably. Food noise — the background mental chatter about what and when you will eat next — quiets down, and for many patients that is more striking than the physical fullness.
It is also when side effects peak. Nausea is most likely in the 24 to 48 hours after your injection. Constipation builds quietly and catches people off guard around week six.
- Eat smaller portions more often rather than three full meals
- Stop eating at the first sign of fullness, not when the plate is clear
- Fibre and water are not optional — start before constipation does
- Avoid high-fat and fried food on injection day
Weeks 9–12: momentum, and the first plateau scare
Weight loss becomes consistent and visible. Clothes change before the scale does anything dramatic, which is why measurements and photos beat daily weigh-ins.
Somewhere in here most patients hit a week where the scale does not move. This is normal. Weight loss is not linear, and a flat week after four good ones is not a plateau — it is a Tuesday.
What to bring to your check-in
Your provider is adjusting based on two things: how much weight you have lost and how well you are tolerating the dose. Come with specifics.
- Weight trend, not a single reading
- Which side effects, how severe, and how long after dosing
- Whether you are hitting protein targets
- Anything that changed — new medication, illness, travel
The three hardest weeks
In our experience the difficult ones are week two, week six and week ten. Week two is when the novelty wears off and nothing has happened yet. Week six is peak side effects. Week ten is the first flat week.
None of these means the treatment is not working. All three are the point where people quit.
This is education, not a prescription. Doses, targets and schedules described here are illustrative. What is right for you depends on your history, your labs and your provider’s judgement.