This is a Bayesian re-analysis of published timepoint data from six studies, 10 treatment arms and 1,776 participants who stopped semaglutide or tirzepatide. Observed follow-up ran from 4 to 52 weeks. The model estimated weight at the point of stopping, the monthly regain rate, and the time to give back half the loss.
Weight loss at cessation averaged 15.35 kg (95% credible interval 11.18 to 19.60). Regain then ran at 1.04 kg per month (95% credible interval 0.80 to 1.29). Half the lost weight was projected back by 7.50 months (5.05 to 10.57), and full return to baseline by 15.00 months (10.10 to 21.13). Tirzepatide regained numerically faster in unadjusted analysis, but no clear drug-specific difference survived adjustment. Larger initial loss trended towards faster regain, and behavioural support towards slower regain, but both intervals included no effect.
This matters because stopping is common and rarely planned. In Indian practice, where these drugs are paid for out of pocket and monthly cost drives most discontinuations, a patient who stops after a good year is on a predictable trajectory back to where they started. The consultation that follows a stop is not a routine review — it is the intervention.
When a patient signals that cost, supply or side effects will end treatment, plan the exit before it happens: a maintenance dose if any dose is affordable, a resistance training and protein plan, and a weight check at six to eight weeks rather than at the next annual visit. Say plainly that the weight will return without a plan, so a patient who regains does not read it as personal failure.
- Ask at every visit whether the patient can still afford the next three months — the answer predicts the trajectory better than the current weight does
- Before a planned stop, agree a maintenance plan: lowest affordable dose if possible, protein target, progressive resistance exercise
- Book a weight check six to eight weeks after stopping, not at the next routine review
- Re-check HbA1c after cessation in patients with type 2 diabetes — glycaemia tracks the weight back up
- Tell the patient the regain is pharmacological, not a failure of willpower, before it starts
The statistics, in plain English
The regain rate itself is well estimated: a credible interval of 0.80 to 1.29 kg per month means the data are consistent only with clinically meaningful regain. The longer projections are weaker. Observed follow-up stopped at 52 weeks, so the 15-month return-to-baseline figure comes from assuming the regain line stays straight — a real possibility is that it flattens as weight approaches the old set point. Treat the monthly rate as evidence and the two-year picture as a model.
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