Injection Day Playbook (Wegovy / Mounjaro): What to Do Before, On the Day, and After Your Dose

Injection day can feel intimidating at first, especially if you’ve had nausea, reflux, or fatigue before. The goal of an “injection day playbook” isn’t to overthink it. It’s to make the day predictable, reduce avoidable side effects, and help you stay consistent.

This guide is a practical routine you can repeat weekly for Wegovy (semaglutide) or Mounjaro (tirzepatide). Always follow your prescriber’s instructions and the patient leaflet for your specific pen.

The night before: set yourself up for an easier dose day

1) Choose a sensible meal
A common side-effect trigger is a heavy, high-fat dinner before injection day. Keep your evening meal:

• smaller than usual

• lower in grease and spice

• balanced (protein + carbs + veg)

2) Hydrate earlier (not all at once)
Aim for steady fluids during the afternoon/evening. Going into injection day slightly dehydrated can worsen headaches, nausea, and constipation.

3) Keep alcohol minimal (or skip it)
Alcohol can worsen dehydration, reflux, and nausea, especially around dose day.

4) Sleep is part of the plan
Poor sleep increases cravings and nausea sensitivity. Even a 20–30-minute earlier bedtime helps.

The morning of injection day: keep it calm and simple

1) Eat something light
Some people feel better with a small meal first; others prefer a light snack. Either way, avoid injecting on a completely empty stomach if that makes you nauseous.

Good options:

• yoghurt / skyr

• toast + egg

• banana + a few nuts

• a small bowl of porridge

2) “Protein first” without forcing it
If your appetite is low, aim for a small protein anchor rather than a big meal.

3) Plan your day
If you tend to get side effects, choose a dose time that gives you a calmer window afterwards (for many people: evening before a quieter day, or morning when you can keep meals simple).

Injection step-by-step: reduce mistakes and anxiety

1) Pick your injection site
Common sites include the abdomen, thigh, or upper arm (depending on your product instructions). Rotate sites weekly to reduce irritation.

2) Check your pen and dose

• Confirm it’s the correct medication and dose.

• Check expiry date and storage instructions.

• If anything looks unusual (cloudiness when it shouldn’t, damage), don’t use it, contact your pharmacy/clinic.

3) Inject slowly and steadily
Rushing increases anxiety and can cause technique errors. Follow the manufacturer’s holding time guidance (your leaflet will specify how long to keep the pen pressed).

4) Don’t rub the site
If there’s mild redness, leave it alone. Rubbing can irritate the skin.

The first 24 hours after your injection: side-effect prevention mode

This is where most people win or lose injection day comfort.

1) Keep meals smaller
Big portions (especially fatty foods) can trigger nausea and reflux. Think “light and steady.”

• soups, rice, toast

• lean protein

• cooked veg

• avoid greasy takeaways on dose day if you’re prone to symptoms

2) Eat slowly
GLP-1s slow stomach emptying, fast eating is a fast track to feeling overfull.

3) Hydrate like it’s your job
Sip regularly. If you’ve had vomiting/diarrhoea, consider oral rehydration (check suitability with a pharmacist).

4) Plan a constipation strategy early
Constipation can build over days. Start early with:

• fluids

• gentle movement (short walks)

• gradual fibre (don’t suddenly overload fibre if you bloat easily)

5) Keep reflux triggers low
For reflux-prone people:

• avoid lying down after meals

• keep dinner smaller

• reduce spicy/fatty foods and late-night snacks

“If X happens, do Y” quick fixes

ü  If nausea hits: smaller meals, bland foods, ginger/peppermint tea if tolerated, avoid greasy foods.

ü  If reflux hits: smaller meals, upright posture after eating, avoid late dinner.

ü  If constipation builds: fluids + walking + gradual fibre; speak to a pharmacist if persistent.

ü  If fatigue/headache hits: fluids + protein; check you’re not severely under-eating.

Red flags: when to contact your clinic urgently

Get same-day medical advice if you have:

• severe, persistent abdominal pain (especially radiating to the back)

• repeated vomiting and inability to keep fluids down

• signs of dehydration (dizziness, very dark urine, fainting)

• blood in vomit/stool or black stools

• symptoms of allergic reaction (swelling, wheezing, breathing difficulty)

Weekly routine: make injection day sustainable

A simple “repeatable” pattern works best:

• Day before: lighter dinner + hydrate

• Injection day: small protein-based meals + steady fluids

• Day after: normalise protein + add a walk + watch constipation

Quick FAQ

1.     Should I change my injection day?
If side effects disrupt work/life, ask your prescriber about switching to a day that gives you a calmer window.

2.     Can I exercise on injection day?
Light movement is usually fine, but if you feel dizzy or under-fuelled, prioritise hydration and food first.

3.     Do I need to eat a “special” meal?
No, just keep it smaller, lower-fat, and easy to digest.

The best injection day playbook is boring, small meals, steady hydration, slower eating, and a calm schedule. Boring is exactly what keeps side effects manageable and helps you stay consistent.