Verbatim response from Perplexity
On GLP-1 medications, weight loss is usually not immediate but starts within weeks, with appetite changes often appearing in the first few days to a few weeks and more measurable weight loss building over months.[4] In many studies and clinical summaries, people lose about 10%–15% of body weight over several months on semaglutide-class treatment, while tirzepatide trials have shown losses up to about 20% at higher doses.[3][6]
Whether it is sustainable depends on whether you stay on treatment. The strongest evidence says weight loss is much more durable while taking the drug, but a lot of regain happens after stopping, including a semaglutide trial extension in which participants regained about two-thirds of prior weight loss within 1 year after discontinuation.[1][5] At the same time, more recent follow-up data suggest some people keep off at least part of the weight even 2 years after stopping, but a meaningful share still regain fully.[2]
What this means in practice:
- Fastest early change: appetite suppression in days to weeks.[4]
- Typical visible weight loss: often noticeable by 3–6 months, with larger losses by ~1 year.[3][4]
- Most sustainable pattern: best results usually come from long-term use plus diet, activity, and behavior changes.[1][3][6]
- If you stop: expect some regain risk, and for many people, substantial regain unless other supports are in place.[5][6]
A practical benchmark from Cleveland Clinic is that losing more than 5% of body weight in the first 3–4 months suggests a better chance of maintaining loss over time.[4] For tirzepatide, losing 10%–15% by 6 months is also associated with better 1-year maintenance.[4]
If you want, I can also give you a month-by-month expectation for semaglutide vs tirzepatide, or help you estimate a realistic range based on your starting weight.