GLP-1 side effects, week by week

GLP-1 side effects follow a predictable pattern: heaviest in the first two weeks, returning at each dose escalation, then easing through maintenance. The most common are nausea, fatigue, appetite suppression, and GI symptoms — all dose-dependent and self-limiting in most users.[¹][²] This page covers what to expect week by week, and the symptoms that warrant a call to your doctor.

Weeks 1–4 — starting dose

Typical starting dose for semaglutide is 0.25 mg weekly; tirzepatide is 2.5 mg weekly. Symptoms users commonly report:

• Mild to moderate nausea, especially day 1–2 after the injection
• Fatigue — particularly afternoon energy dips
• Loss of appetite — most users report dramatic reduction in hunger by week 2
• Constipation
• Headaches in the first 7–10 days

Weeks 5–12 — first titration steps

Dose escalates: semaglutide to 0.5 then 1.0 mg; tirzepatide to 5.0 then 7.5 mg. Each escalation typically brings a fresh wave of GI symptoms for 5–10 days.

• Nausea returns at each step-up — usually milder than week 1 but real
• "Sulphur burps" or "egg burps" reported by ~10–15% of users at higher doses
• Continued appetite suppression
• Possible reflux or heartburn

Weeks 13–24 — approaching peak dose

Dose escalates further: semaglutide to 1.7 then 2.4 mg; tirzepatide to 10 then 12.5 then 15 mg. Most users reach their peak dose somewhere in this window.

• GI symptoms generally easier than during escalation
• Fatigue may persist or improve depending on individual
• Plateaus possible — weight loss is rarely linear
• First reports of "Ozempic face" appearance in users who lost weight fastest

Months 7–12 — maintenance phase

Most users settle into a rhythm. Side effects are typically minimal at this stage. New issues that may emerge:

• Reduced enjoyment of food — some users miss the social pleasure
• Loose skin if weight loss has been rapid
• "Ozempic face" appearance — most pronounced in users who lost weight fastest
• Plateaus that may require a Plateau Breaker reset

When to call your doctor

• Severe abdominal pain (especially if persistent) — possible pancreatitis
• Vomiting that prevents you from keeping liquids down
• Signs of dehydration — dark urine, dizziness on standing
• Vision changes
• Signs of gallbladder issues — right upper-quadrant pain, fever

What Muscle Guard tracks for you

The Personal Coach surfaces side-effect clusters before they derail your week. The Clinical Report colour-codes symptoms by severity, clustered by week — so when you do bring this to your doctor, they see the pattern in 60 seconds, not 12 weeks of guessing.

Muscle Guard is a self-tracking companion and coach. Not a medical device. Not medical advice. Always consult your healthcare provider for personal decisions.