Tirzepatide
Copies two natural gut hormones that control blood sugar and appetite. Used for type 2 diabetes, weight management and sleep apnoea with obesity.
Brand names
- Mounjaro (weekly injection pen)
How it works
Tirzepatide acts on two hormone receptors, GIP and GLP-1, released after eating. Together they boost insulin when blood sugar is high, lower glucagon, slow stomach emptying and reduce appetite. Acting on both receptors is thought to explain its larger effect on weight.
Used for
- Type 2 diabetes, alongside diet and exercise
- Weight management in people with obesity, or overweight with a weight-related condition, alongside diet and activity
- Moderate to severe obstructive sleep apnoea in adults with obesity
Side effects
How often, from the official product information. Bold = serious.
Very common more than 1 in 10
- Nausea
- Diarrhoea
- Vomiting, constipation and tummy pain, especially at weight-loss doses
- Less appetite
- Low blood sugar, if also on insulin or a sulfonylurea
Common 1 in 10 to 1 in 100
- Allergic reactions such as rash or itch
- Dizziness
- Low blood pressure
- Indigestion, reflux, burping, wind or bloating
- Gallstones or gallbladder inflammation
- Hair thinning
- Injection-site reactions
- Tiredness
- Faster heart rate
- Raised pancreatic enzymes on blood tests
Uncommon 1 in 100 to 1 in 1,000
- Pancreatitis (inflamed pancreas)
- Slower stomach emptying
- Altered taste or unusual skin sensations
- Injection-site pain
Rare 1 in 1,000 to 1 in 10,000
- Anaphylaxis (severe allergic reaction)
- Angioedema (swelling of the face, lips or throat)
Get help urgently if
- Severe tummy pain that won’t settle, sometimes going through to the back (possible pancreatitis)
- Pain under the right ribs, fever or yellow skin (possible gallstones)
- Vomiting or diarrhoea so bad you can’t keep fluids down (risk of dehydration and kidney problems)
- Swelling of the face or throat, or trouble breathing
- Shakiness, sweating or confusion if you also take insulin or a sulfonylurea (low blood sugar)
Good to know
- Can make the contraceptive pill less effective. Use a non-pill method or condoms for 4 weeks after starting and after each dose increase.
- Not for use in pregnancy. Stop at least 1 month before trying to get pregnant.
- Not suitable with a personal or family history of medullary thyroid cancer or MEN2.
- Tell your doctor before any surgery or anaesthetic.
- Weight often returns after stopping. Protein and strength exercise help protect muscle.
Information only. Not a recommendation or endorsement of any product. Whether a medicine suits you depends on your health and other medicines, so talk to your doctor or pharmacist. In an emergency, call 000.
More information
maladywise.com/drugs/tirzepatide/