Plateau on Wegovy or Mounjaro: Why Weight Loss Stalls (and What to Tweak Before You Assume it’s “Stopped Working”)

If you’ve been losing weight on Wegovy (semaglutide) or Mounjaro (tirzepatide) and then the scale suddenly stops moving, it can feel frustrating and confusing. A plateau doesn’t always mean the medication has failed. In most cases, it’s your body adapting, your routine shifting without you noticing, or a few “hidden” factors stacking up.

Here are the most common reasons plateaus happen and the practical changes that often restart progress.

First: what counts as a plateau?

A true plateau is usually 4+ weeks with no meaningful change in weight (or waist measurements), despite consistent dosing and routine. A week or two of slower loss is common, especially after a dose change, illness, travel, or a stressful period.

Why plateaus happen on GLP-1s

1) Your daily movement (NEAT) drops without you realising

GLP-1s reduce appetite and often reduce overall energy intake. That can unintentionally lower NEAT (non-exercise activity thermogenesis): walking less, sitting more, fewer errands, less fidgeting. NEAT can make a big difference over weeks.

Try this:

• Add a simple baseline: 20–30 minutes walking daily or a step target you can keep.

• “Movement snacks”: 5 minutes after meals, short stairs/walk breaks.

2) You may be eating too little (yes, that can stall loss)

When appetite is very low, it’s easy to under-eat protein and overall calories. That can increase fatigue, reduce movement, and in some people increase water retention and constipation. It can also increase muscle loss, which slows metabolism over time.

Try this:

• Go “protein first”: aim for a protein portion at every meal.

• Use small, easy options if appetite is low: yoghurt, eggs, tofu, lentils, fish, protein shakes (if suitable for you).

3) Protein is low and muscle is dropping

Rapid early weight loss can include lean mass if protein and resistance training are missing. Less muscle = lower energy burns at rest.

Try this:

• Add 2–3 sessions/week of basic resistance training (home workouts count).

• Prioritise protein consistently, not only “good days.”

4) Constipation and slow gut can mask fat loss

On Wegovy/Mounjaro, constipation is common. If you’re backed up, the scale can look “stuck” even when you’re losing fat.

Try this:

• Hydration first, then fibre gradually, then movement.

• If constipation persists, speak to a pharmacist/clinician for safe options.

5) Sleep and stress are quietly blocking progress

Poor sleep increases cravings, reduces daytime movement, and can increase water retention. Stress can do the same.

Try this:

• A simple wind-down routine: same bedtime, screens off 30 minutes earlier, magnesium only if appropriate for you.

• Aim for consistency over perfection.

6) “Calories creep” returns (small bites count)

When side effects fade and appetite returns a bit, your intake can rise without you noticing a handful here, a latte there, extra oil while cooking, grazing at night.

Try this:

• Do a 3-day reality check (not forever tracking): note drinks, snacks, sauces, oils.

• Swap “liquid calories” first: sugary drinks, alcohol, fancy coffees.

7) You may need more time at a dose (or a review)

Some people respond better by staying longer at a dose rather than moving up quickly. Others may need a clinician review to check dosing, adherence, or whether another factor is interfering.

Try this:

• Keep a simple log for 2 weeks: dose day, side effects, protein, steps, bowel pattern, sleep.

• Use that log to have a more productive conversation with your prescriber.

What to do this week: a simple plateau reset plan

For the next 7 days, focus on the basics:

1. Protein-first meals (3–4 protein “anchors” daily)

2. Daily walking (20–30 min or a realistic step target)

3. Strength training 2x (15–25 min sessions)

4. Hydration + constipation support

5. Sleep routine (same bedtime/wake time most days)

If your plateau is mostly “scale stuck,” also track waist measurement and how clothes fit. Body composition can improve even when the scale lags.

When to contact your clinic

Speak to your prescriber if:

• plateau lasts more than 4–6 weeks despite routine changes

• you can’t eat enough to function (fatigue, dizziness, weakness)

• persistent vomiting, severe reflux, or ongoing diarrhoea/constipation

• you suspect your injection technique, timing, or dose schedule is off

Quick FAQ

1.     Is a plateau normal?
Yes, very common after early rapid loss.

2.     Should I jump up a dose to break it?
Not without clinician guidance. Fix routine factors first.

3.     Does exercise matter if I’m on GLP-1?
Yes, especially strength training to protect muscle and metabolism.

Bottom line: Wegovy and Mounjaro are powerful tools, but plateaus usually respond best to protein, movement, strength training, sleep, and gut regularity before dose changes.