GLP-1 side effects week by week

A week-by-week walkthrough of what most GLP-1 users experience during titration, peak dose, and plateau. Every body is different — this is a typical pattern, not a prediction. Track yours with Muscle Guard and bring the data to your next consult.

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 — common, mitigated by hydration and fibre
• Occasional headaches

Action: focus on hydration (2-3 L water daily), protein (start the day with at least 25 g), and walking (light activity helps GI symptoms).

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
• First visible weight loss — typically 4-8% of starting weight
• Sleep disruption in some users (vivid dreams especially)

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
• "Food blankness" — nothing sounds good, even foods you love
• Muscle loss becomes visible if not actively prevented

Action: this is when protein and training matter most. Aim for the upper end of the 1.2-1.6 g/kg/day range and consistent resistance training.

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
• Hormonal shifts reported in some users (menstrual changes, mood)

When to call your prescriber

• 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
• Severe mood changes or thoughts of self-harm
• Persistent or worsening fatigue

For non-urgent concerns, log them in Muscle Guard and bring the Doctor PDF to your next consult. The timeline view makes the conversation much faster.

Track your side effects with Muscle Guard →