Incretin-Based Medicines: Which Clinical Outcomes Have Been Measured
Which clinical outcomes trials of GLP-1 and GIP-based medicines have measured, from weight and blood sugar to heart events, with the limits and drug-specific differences.
Content last updated . This page has not been medically reviewed.
Quick answer
Medicines based on incretin hormones have been studied for several different outcomes. "GLP-1 drug" is not one product with one set of results, and trial findings in one population do not carry over to another. This page lists what was measured and where the evidence is limited. It gives no dosing, switching or prescribing advice; those belong to the prescriber and the regulator's label. Product details are on GLP-1 medicines. The biology is on GLP-1 and GIP biology.
Evidence labels: approved medicine (named regulator and indication), established, promising but limited, mixed, insufficient evidence.
Outcome types, kept apart
| Outcome type | Examples | Note |
|---|---|---|
| Biomarker | Blood sugar measures, blood pressure, lipids | Not the same as events people feel or experience |
| Body weight | Percent weight loss | A measured outcome, but not by itself a health event |
| Clinical events | Heart attack, stroke, cardiovascular death, heart failure | Direct measures of benefit or harm |
| Safety | Stomach side effects, stopping the drug | Reported alongside benefits |
Weight outcomes
A 2025 pipeline review reports typical weight loss of 6 to 8 percent for liraglutide 3.0 mg, about 12 to 15 percent for semaglutide 2.4 mg, and about 20 percent for tirzepatide in people with obesity but without diabetes. [1] These are percentages from the labeled products and trials, not promises for individuals, and the review notes the open question of maintaining weight loss, possibly requiring long-term treatment. [1] Another review reports weight loss up to 24 percent for newer agents. [2]Heart and blood vessel outcomes
- People with obesity and heart disease, no diabetes. The SELECT trial enrolled 17,604 patients aged 45 or older with preexisting cardiovascular disease and a BMI of 27 or more. A main event (cardiovascular death, nonfatal heart attack or nonfatal stroke) occurred in 6.5 percent on semaglutide 2.4 mg and 8.0 percent on placebo (hazard ratio 0.80; 95 percent CI 0.72 to 0.90). Treatment stopped because of adverse events in 16.6 percent versus 8.2 percent. The trial was funded by Novo Nordisk. [3] Label: promising, with strong trial evidence for this specific population and product.
- People with type 2 diabetes. An umbrella review of 17 meta-analyses covering 432 randomized trials found reduced risk of heart failure and peripheral artery disease (both low certainty), and drug-specific benefits for liraglutide, albiglutide and dulaglutide on specific cardiovascular events. [4] The certainty varied by outcome.
- Real-world studies are observational. One 2026 analysis of US records reported lower all-cause mortality with GLP-1 use in people with heart disease and overweight, but such data cannot prove cause. [5]
Other outcomes in the literature
Reviews link GLP-1-based medicines to obesity complications including diabetes, fatty liver disease, heart failure and atherosclerosis, but describe mechanisms as well as outcomes, and development of newer combinations is still in phase 2 and 3. [2][1] For brain diseases such as Alzheimer's and Parkinson's, incretin receptors are described as a promising strategy; evidence there is early (trials underway), so label it insufficient evidence of benefit for now. [6]What the evidence does not show
- It does not show that results from one drug apply to a different drug, a compounded copy or an unapproved product. See compounded and unapproved GLP-1 products.
- SELECT was funded by the manufacturer, and its mean follow-up was about 40 months, so longer-term outcomes are less certain. [3]
- Weight, glucose and cardiovascular events are different outcomes; improvement in one does not guarantee improvement in another. See biomarker changes versus meaningful health outcomes.
Related reading
Weight research and evidence and prediabetes, type 2 diabetes and metabolic syndrome.Frequently asked questions
Do all GLP-1 medicines have the same results?
No. Drug-specific analyses show different effects on cardiovascular events for liraglutide, albiglutide and dulaglutide, and weight loss differs by product. [4][1]
Did semaglutide reduce heart events in people without diabetes?
In SELECT, in adults with existing heart disease and overweight or obesity, the main event rate was lower on semaglutide 2.4 mg than placebo (hazard ratio 0.80). [3]
How much weight did people lose?
Review figures are roughly 6 to 8 percent for liraglutide 3.0 mg, 12 to 15 percent for semaglutide 2.4 mg and about 20 percent for tirzepatide, in specific trial populations. [1]
What are the usual side effects?
Mainly nausea, vomiting, constipation or diarrhea. Ask the prescriber about your own situation. [1]
Is weight loss a clinical outcome?
It is a measured outcome, but patient-relevant events like heart attack or stroke are separate outcomes that need their own trials. [3]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety signals
Reported side effects are mainly gastrointestinal: nausea, vomiting, constipation or diarrhea. [1] In SELECT, discontinuation because of adverse events was higher than placebo. [3] Reviews also raise concern about loss of lean body mass. [7] Full safety information is in each product's label.
References
- The promise of GLP-1 receptor agonists for the treatment of obesity: phase 2 and 3 pipelines. Expert Opinion on Investigational Drugs 2025. Read 2026-10-22.
- GLP-1-based medications: Mechanisms involved in obesity treatment. Medicina Clinica 2025. Read 2026-10-22.
- Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. New England Journal of Medicine 2023 (SELECT). Read 2026-10-22.
- Efficacy and safety of GLP-1 receptor agonists across all health outcomes in type 2 diabetes: an umbrella review. Diabetes, Obesity and Metabolism 2026. Read 2026-10-22.
- GLP-1 receptor agonists and cardiovascular outcomes in patients with ASCVD and obesity without diabetes. American Journal of Cardiology 2026. Read 2026-10-22.
- Antidiabetic agents as a novel treatment for Alzheimer's and Parkinson's disease. Ageing Research Reviews 2023. Read 2026-10-22.
- Amylin: emergent therapeutic opportunities in overweight, obesity and diabetes mellitus. Nature Reviews Endocrinology 2025. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.