Does Your Body Get Used to Tirzepatide and Stop Working? (October 2026)

01 · Next steps

What to do if your weight loss stalls

Start with the basics, because a stall is usually a plateau rather than a failed treatment. Weight loss on Mounjaro is not linear, and plateaus of a few weeks are normal as the body adapts to a lower weight.

A plateau is not a reason to double doses or add unlicensed products.¹ Your first 2.5mg pen costs £129.99 with code FIRST40 (standard price £169.99), and you can see every strength on the Mounjaro pen page. If you would like a prescriber to review your progress, start your free consultation.

02 · Reality check

Is it adaptation or has it stopped working?

Most stalls are adaptation, and trial averages show why patience matters. Three months in, most people are still on the lower rungs of the dose ladder, so a sensible expectation is mid single digits as a percentage of body weight, with wide individual variation. In SURMOUNT-1, average loss built month by month, with the full averages measured at 72 weeks.² Slower early progress does not predict failure.

See also our guides on whether Mounjaro stops working and getting used to GLP-1 medicines.

Related guide: Buy Mounjaro.

03 · Trial results and pace

What the trials show about pace

In SURMOUNT-1 (2,539 adults), people taking tirzepatide alongside diet and exercise lost on average 15% of body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone. For someone starting at 100 kg, 20.9% is about 21 kg. These are trial averages and individual results vary.²

Think in months, not days, and judge progress by trend rather than single weigh-ins. The first weeks on 2.5mg are an adjustment phase, and most measurable progress builds from 5mg onward.¹ Our guide to how long it takes to get used to Mounjaro covers the early weeks.

04 · When prescribers step in

When your prescriber will review

If you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, your prescriber will discuss whether continuing or stopping is right for you.¹ Our ongoing monthly clinical reviews are included, and repeat orders re-check suitability. Read more on Mounjaro over time.

05 · Stopping and regain

Why stopping is not the answer to a plateau

Mounjaro manages weight; it does not cure the biology behind it. In SURMOUNT-4, people who stopped tirzepatide after 36 weeks regained on average 14% of body weight over the following year, while those who continued lost a further 5.5%.¹⁴ Plan any stop with your prescriber. Regular activity also helps protect against regain.¹