Semaglutide (and Cagrilintide Context) Results Timeline: What Studies Measured, and When

Questions about how quickly semaglutide "works" are, in the published literature, questions about trial design: investigators chose measurement timepoints in advance, and those timepoints determine what is known. This page walks through the schedule used in major randomised trials — which endpoints were assessed at which week, in which populations, and what the researchers reported. This page is for educational purposes only and is not medical advice; consult a licensed physician about any medical condition, medication or treatment decision. Semaglutide is a prescription medicine, and every question about whether, when or how it might be used belongs with a prescribing clinician.

What a "results timeline" means in trial terms

Randomised trials do not observe participants continuously. They specify a primary endpoint at a fixed week, plus secondary endpoints at intermediate visits. A 68-week trial reports its headline number at week 68; the shape of the curve before that is descriptive. Group averages also hide wide individual variation — the published mean change is not a forecast for any single person. With that framing, the timepoints below are what the cited trials actually measured.

The shortest timepoints: appetite, energy intake and gastric emptying

Mechanistic trials used far shorter horizons than weight-loss trials. A randomised controlled trial of oral semaglutide in adults living with obesity measured ad libitum energy intake, appetite ratings, control of eating and gastric emptying, and the researchers reported reduced energy intake and improved control-of-eating scores with oral semaglutide compared with placebo (PMID 39082206). For context on how such endpoints are timed in a related drug class, a 28-week study in people with type 2 diabetes measured appetite, energy intake and fat mass with tirzepatide and reported reductions in all three (PMID 36857477). These designs show that intake-related endpoints were assessed over weeks, while body-composition and outcome endpoints required far longer.

Week 20: the one trial that measured a mid-course timepoint by design

STEP 4 is unusual because its design made week 20 a formal measurement point. All participants received escalating once-weekly semaglutide to 2.4 mg during a 20-week run-in, and the study reported a mean weight loss of about 10.6% from baseline by week 20 before randomisation (PMID 33755728). Participants were then randomised to continue semaglutide 2.4 mg or switch to placebo for a further 48 weeks, and researchers reported a further mean change of −7.9% with continued treatment versus +6.9% with placebo from week 20 to week 68 (PMID 33755728). That contrast is the clearest published illustration that the trajectory measured in these trials depended on continued treatment.

Weeks 68 to 72: the primary weight endpoints

Most of the large obesity trials chose 68 or 72 weeks as the primary timepoint.

• In adults with overweight or obesity without diabetes, the study randomised participants to once-weekly semaglutide 2.4 mg or placebo plus lifestyle intervention for 68 weeks, and reported a mean body-weight change of −14.9% versus −2.4% with placebo at week 68 (PMID 33567185).
• In adults with overweight or obesity and type 2 diabetes, researchers reported mean weight changes at week 68 of −9.6% with semaglutide 2.4 mg, −7.0% with 1.0 mg and −3.4% with placebo (PMID 33667417). The smaller magnitude in the diabetes population is one of the clearest population effects in this literature.
• In adults with obesity and knee osteoarthritis, the trial measured both body weight and pain at week 68 and reported a mean weight change of −13.7% with semaglutide 2.4 mg versus −3.2% with placebo, alongside a greater reduction in WOMAC pain score (PMID 39476339).
• A phase 3b trial of once-weekly semaglutide 7.2 mg in adults with obesity used a 72-week treatment period and compared 7.2 mg with 2.4 mg and placebo, with researchers reporting greater mean weight reduction at the higher dose (PMID 40961952).

A head-to-head trial comparing tirzepatide with semaglutide for the treatment of obesity also used a 72-week timepoint, and the study reported greater mean weight reduction with tirzepatide than with semaglutide at that visit (PMID 40353578). Comparative framing of this kind only holds at the timepoint and in the population actually studied.

Months to years: cardiovascular and outcome endpoints

Outcome trials operate on a completely different clock, because they count events rather than measure a variable at a visit. In patients with type 2 diabetes at high cardiovascular risk, a trial of semaglutide 0.5 mg or 1.0 mg once weekly ran for 104 weeks and reported a primary composite outcome in 6.6% of the semaglutide group versus 8.9% of the placebo group (hazard ratio 0.74) (PMID 27633186). In adults with obesity and established cardiovascular disease but without diabetes, researchers reported a primary cardiovascular composite endpoint in 6.5% with semaglutide 2.4 mg versus 8.0% with placebo (hazard ratio 0.80) over a mean follow-up of about 39.8 months (PMID 37952131). A prespecified analysis of that same trial examined participants with prevalent heart failure and reported that cardiovascular findings were consistent in that subgroup (PMID 39181597). None of these timelines is a "results" timeline in the everyday sense; they are statistical accrual periods lasting years.

After stopping: what the extension measured

One extension study followed participants after treatment ended. Researchers reported that one year after withdrawal of once-weekly semaglutide 2.4 mg and lifestyle intervention, participants had regained about two-thirds of their prior weight loss, with cardiometabolic variables reverting toward baseline in parallel (PMID 35441470). Read alongside the withdrawal arm of STEP 4, in which switching to placebo was followed by a mean +6.9% weight change from week 20 to week 68 (PMID 33755728), this is the part of the timeline most often omitted from popular summaries.

Timepoint reference table

Cagrilintide context: what this page's evidence set does and does not contain

Cagrilintide is an investigational amylin analogue that has not been approved as a medicine. Plainly stated: no cagrilintide trial appears in this page's verified citation set, and therefore no cagrilintide results timeline — alone or in combination with semaglutide — is described here. Readers encountering timeline claims about cagrilintide or combination products elsewhere should check whether those claims are attached to a specific published trial, its population and its measurement week, since none of the semaglutide timepoints above transfer to a different molecule or a different combination.

Adverse Events: What Studies Report

Tolerability findings also arrive on a timeline. In the 68-week trial in adults with overweight or obesity, researchers reported that nausea and diarrhoea were the most common adverse events with semaglutide, that they were typically transient and mild to moderate in severity, and that more participants discontinued because of gastrointestinal events with semaglutide than with placebo (PMID 33567185). The trial in participants with type 2 diabetes similarly reported that gastrointestinal adverse events were more frequent with semaglutide than placebo over 68 weeks (PMID 33667417). Over the longer 104-week horizon, the study in type 2 diabetes reported a higher rate of diabetic retinopathy complications with semaglutide than placebo (PMID 27633186). The higher-dose phase 3b trial of semaglutide 7.2 mg likewise assessed safety and tolerability alongside its 72-week weight endpoint (PMID 40961952). Adverse-event profiles are population- and dose-specific and are a matter for a prescribing clinician, not for self-interpretation.

Why the same drug produced different timelines

Three design features explain most of the variation across these trials. First, population: the week-68 mean weight change was smaller in participants with type 2 diabetes (PMID 33667417) than in participants without diabetes (PMID 33567185). Second, endpoint type: an intake or appetite endpoint can be measured within weeks (PMID 39082206), whereas a cardiovascular composite required years of event accrual (PMID 37952131). Third, continuation: the withdrawal data show that measured changes were tied to ongoing treatment (PMID 35441470).

Regulatory status, stated factually

Semaglutide is a prescription medicine, available in regulated markets in once-weekly injectable and daily oral formulations under brand names authorised for specific indications; the dosing regimens studied above were investigational protocols within controlled trials, not general-use instructions. Cagrilintide remains investigational. Nothing on this page describes an unapproved use, and nothing here is a recommendation. Anyone with questions about eligibility, monitoring, interactions or duration should raise them with a licensed physician who can review their full history.

References

• Once-Weekly Semaglutide in Adults with Overweight or Obesity (New England Journal of Medicine, 2021)
• Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial (JAMA, 2021)
• Semaglutide 2·4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2): a randomised, double-blind, double-dummy, placebo-controlled, phase 3 trial (Lancet, 2021)
• Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension (Diabetes, Obesity & Metabolism, 2022)
• Once-weekly semaglutide 7·2 mg in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial (The Lancet Diabetes & Endocrinology, 2025)
• Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (New England Journal of Medicine, 2023)
• Semaglutide and cardiovascular outcomes in patients with obesity and prevalent heart failure: a prespecified analysis of the SELECT trial (Lancet, 2024)
• Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (New England Journal of Medicine, 2016)
• Once-Weekly Semaglutide in Persons with Obesity and Knee Osteoarthritis (New England Journal of Medicine, 2024)
• Effect of oral semaglutide on energy intake, appetite, control of eating and gastric emptying in adults living with obesity: A randomized controlled trial (Diabetes, Obesity & Metabolism, 2024)
• Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (New England Journal of Medicine, 2025)
• Tirzepatide Reduces Appetite, Energy Intake, and Fat Mass in People With Type 2 Diabetes (Diabetes Care, 2023)