GLP-1 Side Effects: A Week-by-Week Survival Guide for Your First 90 Days

GLP-1 drugs slow gastric emptying. Food that used to leave your stomach in 90 minutes now takes 3–4 hours. Add reduced appetite signaling in the brain and the result is the same set of symptoms in almost everyone: early fullness, nausea, constipation, and a sharp drop in fluid intake that compounds the constipation.

Your body adapts. By week 10–12 most users have minimal day-to-day symptoms. The trick is surviving weeks 1–6.

Mild nausea peaks 36–48 hours after injection. Take your shot in the evening so you sleep through the worst window.

• Eat half your normal portion size. Force yourself to stop when 60% full.
• Avoid greasy/fried food and alcohol for the first 72 hours after each dose.
• Drink 80–100 oz water daily. Add electrolytes if you're light-headed.

Nausea typically returns for 3–5 days after each titration. Constipation peaks here.

• Start a daily magnesium glycinate (300–400 mg) and 2 tbsp ground flax
• Walk 20+ minutes after every meal — motility is movement-dependent
• If you go more than 3 days without a bowel movement, add a stool softener (Colace) before reaching for stimulant laxatives

By now appetite is dramatically lower and you're at risk of under-eating protein.

• Hit 0.7–1.0 g protein per pound of goal body weight
• Lift weights 2–3x/week — without resistance training, 25–40% of your weight loss will be lean mass
• Watch for 'sulfur burps' on tirzepatide: a sign food is sitting in your stomach too long. Smaller, drier meals fix it.

• Severe upper-right abdominal pain (possible gallbladder)
• Persistent vomiting beyond 24 hours
• Dark urine, dizziness, or rapid heart rate (dehydration)
• Sudden severe back pain radiating around the side (possible pancreatitis)