Overview
This article explains the potential side effects of Mounjaro® (tirzepatide), including common, uncommon, and rare reactions, as well as serious symptoms that require urgent medical attention. Use this guide to understand what side effects to expect, when they are most likely to occur, and when to seek medical advice while using Mounjaro for weight loss.
We’re here to support you throughout your weight loss journey with Mounjaro® (tirzepatide), including helping you understand possible side effects and how to manage them.
General information about Mounjaro side effects
While Mounjaro has helped many people reach their health goals, side effects can occur. Most side effects are:
Mild to moderate
More likely when starting Mounjaro or increasing the dose
Likely to improve over time as your body adjusts
Very common side effects of Mounjaro
(May affect more than 1 in 10 people)
Nausea
Vomiting
Diarrhoea
Stomach (abdominal) pain
Constipation
low blood sugar when tirzepatide is used for the treatment of type 2 diabetes
Common side effects of Mounjaro
(May affect up to 1 in 10 people)
Dizziness
Low blood pressure
Indigestion
Heartburn
Bloating
Burping
Flatulence
Fatigue
Injection site reactions (redness, swelling, or pain at the injection site)
Allergic skin reactions (such as rash, itching, or eczema)
Hair loss (often associated with weight loss rather than Mounjaro itself)
Uncommon side effects of Mounjaro
(May affect up to 1 in 100 people)
Injection site pain
Changed sense of taste
Increased heart rate
If any Mounjaro side effects persist, worsen, or cause concern, seek medical advice.
🔴 Serious side effects of Mounjaro – seek urgent medical attention
🔴 Acute pancreatitis
Acute pancreatitis is inflammation of the pancreas. Symptoms may include:
Severe and persistent stomach pain that may spread to the back
Severe vomiting (for example, vomiting three or more times in one day)
Vomit that looks like coffee grounds or contains blood
🔴 Call 999 or attend A&E immediately if you experience symptoms of acute pancreatitis while using Mounjaro.
🔴 Acute gallbladder disease (cholecystitis)
Acute gallbladder disease can cause:
Sudden, sharp pain in the upper right side of the abdomen
Pain that worsens when breathing deeply
A very tender abdomen
🔴Call 999 or attend A&E immediately if you experience symptoms of gallbladder disease while using Mounjaro.
Rare side effects of Mounjaro
(May affect up to 1 in 1,000 people)
🔴 Severe allergic reaction (anaphylaxis)
Symptoms of a severe allergic reaction may include:
Difficulty breathing
Swelling of the lips, tongue, or throat
Difficulty swallowing
Rapid heartbeat
🔴 Call 999 or attend A&E immediately if you experience symptoms of a severe allergic reaction.
Managing Mounjaro side effects
Mounjaro side effects are most common when starting treatment or increasing your dose
Many Mounjaro side effects improve with time
If you experience any side effects , whether listed here or not, please visit our weight loss guide for guidance on what to do
If you are ever unsure or worried about symptoms while taking Mounjaro, seek medical advice promptly.
If you still need help after reviewing the information above, additional assistance is available.