GLP-1 by the numbers

GLP-1 statistics and key facts

The most-cited numbers on GLP-1 medications like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), each with its source. Trial averages describe groups, not individuals; your own results depend on dose, diet, activity, and biology. This is general information, not medical advice.

Average weight loss by medication

These are average results from the main phase 3 obesity trials, alongside lifestyle changes. Individual results vary widely.

~15%average body-weight loss with semaglutide 2.4 mg (Wegovy) over 68 weeks (STEP 1, NEJM 2021)

~20 to 21%average body-weight loss with tirzepatide over 72 weeks, up to about 22.5% at the highest dose (SURMOUNT-1, NEJM 2022)

~8%average body-weight loss with liraglutide 3.0 mg (Saxenda) over 56 weeks (SCALE, NEJM 2015)

Cardiovascular and other outcomes

GLP-1 medications are studied for more than weight, including heart and sleep outcomes.

20% lowerrisk of major adverse cardiovascular events with semaglutide in people with cardiovascular disease and overweight or obesity, without diabetes (SELECT, NEJM 2023)

Superiorblood-sugar (A1c) reduction with tirzepatide compared with semaglutide 1 mg in type 2 diabetes (SURPASS-2, NEJM 2021)

Approvedtirzepatide (Zepbound) for moderate-to-severe obstructive sleep apnea in adults with obesity (SURMOUNT-OSA, 2024)

How they work

GLP-1 medications mimic gut hormones that reduce appetite and slow stomach emptying.

~1 weekhalf-life of semaglutide, which is why it is injected only once weekly (Semaglutide prescribing information)

2 receptorstirzepatide activates both GIP and GLP-1 receptors, while semaglutide targets GLP-1 alone (Prescribing information)

~5 weeksroughly how long it takes semaglutide to mostly clear the body after the last dose, about five half-lives (Semaglutide pharmacokinetics)

US approval timeline

When each brand was first approved by the FDA.

2017Ozempic (semaglutide) approved for type 2 diabetes (FDA)

2021Wegovy (semaglutide) approved for chronic weight management (FDA)

2022Mounjaro (tirzepatide) approved for type 2 diabetes (FDA)

2023Zepbound (tirzepatide) approved for chronic weight management (FDA)

What happens after stopping

GLP-1 medications treat weight as a chronic condition, so stopping usually reverses part of the progress.

~two-thirdsof lost weight was regained on average within a year of stopping semaglutide in the trial extension (STEP 1 extension, 2022)

Common questions

How much weight do you lose on semaglutide?

In the STEP 1 trial, adults on semaglutide 2.4 mg (Wegovy) lost about 15% of their body weight on average over 68 weeks, alongside lifestyle changes. Individual results ranged widely.

Is tirzepatide more effective than semaglutide for weight loss?

On average, tirzepatide produced greater weight loss in trials, about 20 to 21% over 72 weeks in SURMOUNT-1 versus about 15% for semaglutide over 68 weeks in STEP 1, though the trials were separate and results vary by person.

Do you gain the weight back after stopping a GLP-1?

Often, in part. In the STEP 1 extension, participants regained about two-thirds of their lost weight on average within a year of stopping semaglutide, which is why these are viewed as long-term treatments.

Sources are the published phase 3 trials (NEJM) and FDA approval records named beside each figure. For the detail behind these numbers, read our GLP-1 guides or try the weight-loss calculator. DoseLog helps you track how your own results compare over time.