Learn · GLP-1 guides
Your first month on a GLP-1, week by week
Month one is the accumulation month: you start on a low intentionally sub-therapeutic dose (0.25 mg semaglutide / 2.5 mg tirzepatide), your level climbs each week toward steady state, appetite effects appear gradually, and mild GI side effects — if any — usually cluster after dose days and ease as your body adapts. Track from day one; your week-12 self will thank you.
Before week 1: what the starter dose is (and isn’t)
Semaglutide starts at 0.25 mg weekly, tirzepatide at 2.5 mg weekly — and both labels are explicit that these starter doses exist for tolerability, not effect. If week one feels underwhelming, nothing is wrong. Your treatment hasn’t really started yet; your gut is being introduced to it politely.
Week 1: the introduction
- Level: a single dose’s worth — the lowest it will ever be. Peaks 1–3 days after injection.
- Appetite: some people notice quieter “food noise” within days; many notice nothing yet. Both are normal.
- Side effects: if any, usually mild queasiness or fatigue in the 48 hours after the shot.
- Worth doing: log your starting weight, a baseline appetite score, and your injection site. Baselines are the one thing you can’t backfill honestly.
Week 2: the stack begins
Your second dose lands on top of roughly half of the first — average levels are now ~50% higher than week one’s. Appetite effects often become noticeable here: smaller portions feel sufficient, snacking impulses thin out. GI side effects, if present, still cluster after dose day. Rotate your injection site — abdomen, thigh, or upper arm, a different spot than last week.
Weeks 3–4: approaching the first plateau (the good kind)
By week 4 you’re at ~90% of the starter dose’s steady state. Patterns become readable: maybe appetite dips hardest on days 2–4 and rebounds slightly before your next shot — that’s the sawtooth, and it’s worth seeing on a chart rather than doubting yourself. Constipation can appear around here as eating volume drops; fluids and fiber are the standard first response.
End of month: the first escalation decision
Labeled schedules move to the next step after 4 weeks (0.25→0.5 mg semaglutide; 2.5→5 mg tirzepatide) — but the real-world decision is shared between you and your prescriber, and it leans heavily on tolerability. This is where a month of honest logs pays off: “nausea peaked at 4/10 the day after shots and faded by day three” is a decision-grade sentence. “It was okay, I think” is not.
What’s actually worth tracking in month one
| Track | Why it matters later |
|---|---|
| Weight (consistent rhythm) | The trend line every later conversation is built on. |
| Doses + injection sites | Adherence math and healthy rotation. |
| Appetite / food noise (0–10) | The earliest, most sensitive signal the medication is working. |
| Side effects (0–10 severity) | Escalation decisions hinge on this curve. |
| Protein + water | The two intake numbers that quietly fall when appetite drops. |
Red flags that skip the tracking and go straight to a clinician
- Severe or persistent abdominal pain (with or without vomiting)
- Repeated vomiting or signs of dehydration
- Symptoms of an allergic reaction (swelling, breathing difficulty)
- Severe hypoglycemia symptoms if you also use insulin or sulfonylureas
These are label-level warnings, not app material. For everything milder, a good record turns month one from a blur into a baseline.
Sources
- FDA Prescribing Information — Wegovy, Ozempic, Mounjaro, Zepbound — starter doses, titration, common adverse reactions
- Wilding et al., NEJM 2021 (STEP 1) — semaglutide 2.4 mg — GI side-effect timing: mostly mild-to-moderate, early, transient
- Jastreboff et al., NEJM 2022 (SURMOUNT-1) — tirzepatide — adverse-event pattern during escalation
This article is educational and is not medical advice, diagnosis or treatment. Medication decisions — including dose changes and what to do after a missed dose — belong with your prescriber. If you experience severe symptoms, seek medical care.