Weight Loss Injections and Pancreatitis: What UK Patients Should Know (October 2026)

01 · The core answer

Can weight loss injections cause pancreatitis?

Pancreatitis is listed as a warning in the product information for Mounjaro, so it should be treated as a real possibility rather than dismissed.¹ The patient leaflet lists acute pancreatitis as uncommon (up to 1 in 100 people).¹³

A warning means prescribers screen for risk and patients know what to watch for. It does not mean most people will be affected. Regulators monitor reports continuously, which is why the Yellow Card scheme exists.¹⁹ You can read our wider guide to pancreatitis and weight loss drugs for more background.

02 · Your decision

Is this relevant to me, and what should I do next?

It is most relevant if you have had pancreatitis before, or if you develop new symptoms on treatment. If you have severe, persistent stomach pain, stop using Mounjaro and get medical help straight away. If you have a past history, do not start a weight loss injection without discussing it with a prescriber who can see your full history. That is exactly what the consultation is for.

If you are well and considering treatment, the sensible next step is a consultation with a GPhC-registered prescriber. Our weight loss clinic explains the process, and you can see the Mounjaro pen, prices and consultation when you are ready.

Related guides: Government weight loss injections and Colostrum weight loss injections.

03 · Warning signs to act on

Early warning signs and what pancreatitis feels like

The signs that matter most are severe stomach pain that does not settle, particularly with vomiting: get medical help straight away. Pain that spreads towards the back is another reason to get medical help straight away.

Ordinary early side effects are different. Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle.¹ The difference is severity and persistence. Mild queasiness that eases is expected. Intense pain that keeps building is not.

If you are unsure, get medical help straight away and tell the clinician which injection you use. Report suspected side effects via the Yellow Card scheme.¹⁹

04 · Before you start

Can you take weight loss drugs if you have pancreatitis?

A history of pancreatitis is a reason to speak to a prescriber before treatment, not something to work out alone. Whether a weight loss injection is suitable depends on your history, and the product information is the reference point.¹

Be open in your consultation about past pancreatitis, gallbladder problems, other conditions and all medicines you take. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

If you want a broader overview of how ordering works, see our guide to weight loss injections register online.

05 · Lowering your risk

Pancreatitis risk and warning signs on Mounjaro

There is no proven way to prevent pancreatitis or gallbladder problems while taking Mounjaro. Before you start, tell your prescriber if you have ever had pancreatitis, gallstones or gallbladder disease, or severe problems with your digestion. Learn the warning signs: severe, persistent stomach pain that may spread to the back, with or without being sick, could be pancreatitis — stop using Mounjaro and get medical help straight away.

Pain in the upper right of the abdomen, fever or yellowing of the skin or eyes could be a gallbladder problem: get medical help straight away. Signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing also need immediate medical help.

06 · Different injections

Which injection is most likely to cause pancreatitis?

Mounjaro, Wegovy and Saxenda each have their own warnings, and it is not possible to say one is safer than another. Mounjaro (tirzepatide), Wegovy (semaglutide) and daily liraglutide products such as Saxenda all work on gut-hormone pathways, and each product's SmPC sets out its own warnings.¹¹⁸ Be wary of anyone claiming one brand is safe and another dangerous.

Be especially careful with unregulated sellers, including those offering to supply without a consultation or prescription. Those products may be counterfeit, with unknown contents and no safety screening.

For wider context, read weight loss injections FAQs.