I spent three years paying £200 a month for Mounjaro. Then a friend sent me a link that changed the maths entirely.

It's the same compound, in the same kind of weekly pen, at less than half the price. Here's what's actually going on, and what to check before you make the switch.

The tirzepatide weekly pen: the same active compound as Mounjaro, in the same kind of self-injection.

When Claire, a 41-year-old teacher from Manchester, got her first Mounjaro prescription in early 2023, she considered herself lucky. She'd spent years trying to shift the weight she'd put on during her forties, and the 2.5mg weekly injection felt, almost immediately, like it was working. The problem was the bill.

"At 5mg a week I was paying £199 a month. When my dose went up to 7.5mg, it went up to £249. It just kept climbing." By the time she was at 10mg, which her GP said was the right dose for her, she was paying £279 a month. That's over £3,300 a year. "At that point you start thinking: how long can I realistically keep this up?"

A lot of Mounjaro patients are having exactly that conversation right now. And an increasing number of them are arriving at the same answer.

Tirzepatide, the active compound in Mounjaro, is now available through regulated providers as a weekly pen or a lower-cost vial. The mechanism is identical: the same dual GIP/GLP-1 receptor agonist action, the same weekly injection, the same titration from 2.5mg upwards. What's different is the supply chain. That difference is what drives the price.

Branded Mounjaro is manufactured by Eli Lilly and distributed through licensed pharmacies. Compounded tirzepatide is produced by licensed pharmaceutical manufacturers under 503A/B and EU Annex 1 standards, independently batch tested for sterility and potency, and supplied following a clinical assessment. The active compound is the same. You are simply not paying for the Eli Lilly margin, the branded packaging, or the pharmacy markup on top.

What does it actually cost?

This is where it gets interesting, and where the Mounjaro pricing trips people up. A Mounjaro KwikPen holds four weekly doses. So the "2.5mg" KwikPen is actually 10mg of tirzepatide in total, and at a typical pharmacy it costs around £169. That works out at roughly £17 per mg. The same tirzepatide through Elva works out at well under a third of that per mg, and your exact price for each format is shown in the free assessment.

There are two ways to get it: a vial or a pen. The vials come direct from Elva. The pens come from providers that Elva has independently checked and verified. The pens are not always as cheap as the vials, but for most people both still work out well below a branded Mounjaro KwikPen. Rather than guess here, the free assessment shows your recommended option, how long it lasts at your dose, and your exact price.

For most people switching at the lower doses, the same compound works out far cheaper than a branded Mounjaro KwikPen, often a saving of several hundred pounds a year or more. Your exact figures depend on your dose and format, which is why the assessment works them out for you.

But the cost isn't the only thing people ask about. "The first thing everyone wants to know is whether it's the same," says one patient who has been using the pen format for six months. "I can tell you from experience: it is. Same feeling, same pen mechanism, same weekly schedule."

What's included, and what to check

The thing that surprises most people when they switch is that it doesn't feel like a downgrade. If anything, the support tends to be better, because the providers are competing on service rather than brand recognition.

• Your choice of format. A ready-to-inject pen, or a lower-cost vial for those happy with simple reconstitution
• Monthly needles and syringes. Shipped to your door automatically, no separate order needed
• Alcohol wipes. Included with every shipment
• Registered dietitian access. Included, not charged separately
• Patient support team. Available seven days a week
• Full dosing guidance. Step-by-step, from first injection through titration