Your GLP-1 Stopped Working: A Plateau Troubleshooting Guide

It is one of the most common questions asked about this medication, usually somewhere between months four and nine: it was working, and now it isn't.

Almost always, something specific and identifiable is going on. Here is the order a clinician would work through it, starting with the causes that are both most common and easiest to fix.

First: is it actually a plateau?

A genuine plateau is no meaningful change over four to six weeks. Two weeks of a static scale is normal variation, not a stall.

Weight fluctuates by one to two kilograms across a week from fluid, glycogen, salt intake, the menstrual cycle and bowel habit. If you are also strength training, you may be gaining muscle while losing fat — the scale stays still while your body composition improves. Waist measurements and how clothes fit are more informative during this period than weight alone.

Second: have you missed doses?

This is the most common cause and the one people are least likely to volunteer. A delayed or skipped weekly dose interrupts the steady drug levels the treatment depends on, and the effect on appetite is noticeable within days.

Supply problems, travel, holidays and simply forgetting all contribute. This is the specific problem GLP-1 companion apps like Zenday App are built to prevent — dose prompts plus a record of what you actually took and when. That record is also what lets you answer the question honestly, which is harder than it sounds from memory. Never double up to compensate for a missed dose; ask your prescriber what to do.

“A plateau is four to six weeks without change. Two weeks of a static scale is just a week with a lot of salt in it.”WomenWelly, Weight Loss desk

Third: are you at a therapeutic dose?

Plenty of people plateau simply because they stopped escalating — often because side effects were difficult at the time, and the conversation never got picked back up.

Maintenance doses differ by drug and by indication. If you are below the licensed maintenance dose and tolerating your current one well, that is a straightforward conversation to have. See our dose escalation guide.

Fourth: energy requirements have genuinely fallen

This is real physiology rather than a problem to solve. A smaller body needs less energy, so the deficit that produced steady loss at 95kg is not a deficit at 78kg. Weight loss slows and eventually stops at a new equilibrium.

Some additional adaptation occurs beyond what body size predicts, though it is consistently overstated online — our piece on metabolic adaptation covers the actual numbers. The practical response is to protect muscle and raise daily movement rather than cut food further.

Fifth: intake has crept up

As nausea settles and appetite partially returns, intake rises — usually without any conscious decision. Self-reported intake is systematically underestimated, by 20 to 50 percent in validated studies, and this affects dietitians as much as anyone.

Two weeks of honest logging is diagnostic. You are not looking to cut drastically; you are looking to see what changed since month two.

Sixth: the things that are not the medication

Poor sleep raises appetite hormones and lowers energy expenditure. New medications — some antidepressants, steroids, beta blockers — cause weight gain. Untreated thyroid disease matters. Alcohol adds calories that are easy not to count.

A plateau that arrives suddenly alongside fatigue, cold intolerance or hair loss deserves blood tests rather than a stricter diet.

What not to do

Do not cut calories drastically. On a GLP-1 you are likely already eating substantially less than before, and going lower accelerates muscle loss, which lowers the metabolic rate you are trying to protect.

Do not add hours of cardio to a body that is already under-fuelled. Do not change your own dose. And consider whether this is a plateau or an endpoint — arriving at a weight your body will maintain is a successful outcome, not a stalled one.