Most of the time a drug that seems to have stopped working has not. Weight loss slows as you get lighter because a smaller body needs less energy, and intake tends to creep back up as side effects fade. Both are expected. True loss of drug effect is a different and less common explanation.
A plateau and tolerance are not the same thing. A plateau is your energy balance reaching equilibrium. Tolerance would mean the medication itself producing less effect at the same dose. The first is common and expected; the second is invoked far more often than it is demonstrated.
For how this fits into the wider titration picture, see GLP-1 Dosing and Titration: The Complete Guide.
Why loss slows as you go
A lighter body burns less energy at rest and less doing the same activity. So the deficit that produced steady loss at your starting weight produces less at your current one, without anything having changed in what you eat.
This is arithmetic rather than failure, and it happens with every method of weight loss.
The body also adapts beyond the simple size effect, and hormonal signals that promote intake tend to increase after weight loss. This is part of why maintaining loss is harder than achieving it, and part of why medication is often continued rather than stopped at goal.
The intake drift nobody notices
Early on, side effects suppress intake substantially. As they settle, eating becomes comfortable again, and portions quietly return toward where they were.
Nothing about this is a lapse. It is what happens when nausea stops making the decisions.
If you tracked intake at the start and not since, tracking honestly for a few days now is the fastest way to find out whether this is your explanation. Most people are surprised.
The things worth checking first
Dose stage. If you are still titrating, you may simply not be at a dose expected to do much yet.
Storage. A pen that has been frozen or overheated can be degraded while looking entirely normal. Worth reviewing if a plateau coincided with a new pen or a disrupted fridge.
Technique. Incomplete injections happen, particularly if the pen is removed too quickly. Worth having someone watch you once.
Muscle loss. Losing lean mass lowers your energy needs faster than fat loss alone would, which brings the plateau forward. Protein and resistance work address this.
Other causes. Thyroid problems, some medications, and fluid retention all affect the scale independently. If a plateau is prolonged and unexplained, these are worth excluding.
Is a plateau actually a problem
Sometimes it is where you were heading anyway. A stable weight well below where you started, with improved blood pressure, blood sugar or sleep, is a result rather than a stall.
Whether to push further is a clinical conversation about what you are treating, not a foregone conclusion. More loss is not automatically the goal.
What your prescriber can consider
If further loss is clinically indicated, the options include reviewing whether you are at an appropriate dose, addressing muscle loss and protein intake, checking for other causes, and in some cases changing product.
What is not an option is deciding any of this yourself. Increasing your own dose to break a plateau is the single most common self-directed error here, and it produces side effects rather than results.
Plateaus are usually energy balance rather than tolerance, explained in the plateau guide. Raising your own dose is the common error, and what actually signals a dose problem sets out the difference. Storage and technique are worth ruling out too, via storing pens and injection technique.
Frequently asked questions
Do people build tolerance to these drugs?
Plateaus are usually explained by energy balance and intake rather than by loss of drug effect. Discuss your own situation with your prescriber.
Should I increase my dose?
Not on your own judgement. That is a prescriber decision, and a plateau is not automatically a dosing problem.
How long is a normal plateau?
Weeks of stability are common. Months without change, when further loss is intended, is worth investigating.
Would switching drugs help?
Sometimes, and it means re-titrating. Worth discussing rather than assuming.
Could my pen be faulty?
Storage or technique problems are more common than faulty product. Both are worth checking.
Is it worth staying on it if I have stopped losing?
Often yes, since maintaining loss is itself an outcome. That is a conversation about your goals rather than a default answer.