“Your body builds a tolerance and it stops working.”
What the evidence shows
Weight loss on a GLP-1 does slow and level off — but that's expected physiology, not the drug losing its power. In the two-year STEP 5 trial, semaglutide 2.4 mg produced about 15% weight loss that plateaued around week 60 and was then sustained through week 104, with minimal regain while treatment continued. A plateau reflects a new energy-balance equilibrium (a smaller body burns fewer calories, and appetite partially adapts), not tachyphylaxis of the medicine. Some drug effects genuinely do fade with time — notably the delayed stomach-emptying that drives early nausea — but the weight and blood-sugar benefits persist as long as the drug is taken.
What we still don’t know
A minority of people plateau earlier or lower than average, and the reasons — dose ceiling, set-point differences, rare immune responses to the drug, or lifestyle drift — aren't always separable in an individual. Whether switching agents, adjusting dose, or intensifying lifestyle reliably restarts loss is common clinical practice but not cleanly proven in head-to-head trials.
Why the claim misleads
"Builds a tolerance and stops working" borrows the language of opioids or caffeine and misapplies it. The scale stops moving because you've reached a new balance point, not because the medicine quit. The benefit is still being delivered — which is exactly why stopping the drug typically leads to regain. A stalled number is a reason for a clinician conversation about expectations or dose, not evidence the drug has worn off.
Graded by The Peptide Era · evidence, not hype