Weight-loss plateau

A weight-loss plateau is a stretch — weeks or months — where the scale stops moving even though you’re still taking your medication and haven’t changed anything. On GLP-1 treatment, a plateau isn’t a malfunction. It’s built into the shape of the results.

The trial curves flatten too

Look at the weight curves from STEP 1 (semaglutide) or SURMOUNT-1 (tirzepatide): steep loss in the first months, then a gradual flattening, with average weight essentially stable from around week 60 onward. Trial participants — with perfect adherence, at full dose — plateaued. That flat section isn’t the medication failing; it’s the new equilibrium between the medication’s appetite effect and your body’s energy needs at a lower weight.

Why plateaus happen

As you lose weight, your body burns fewer calories at rest (a smaller body needs less energy), an effect amplified by metabolic adaptation — the body’s tendency to lower energy expenditure beyond what the weight change alone predicts. Eventually intake and expenditure meet again, and weight stabilizes.

A plateau vs a fluctuation

Two weeks of a flat or bouncing scale is usually water, sodium, hormones, or measurement noise — not a plateau. A real plateau shows up as a flat trend line over 4+ weeks. This distinction is exactly why a weight trend (weekly average) tells you more than any single weigh-in, and why panicking at day-to-day noise is the most common self-inflicted misery of treatment.