What the published science says about GLP-1s and peptides
We track independent, peer-reviewed and conference-presented research on this drug class as it is published, and summarise it in plain language. Every entry links to its original source so you can read it yourself.
Featured findings
May 2026·ASCO 2026
GLP-1 receptor agonists associated with 31–50% lower risk of metastatic progression in obesity-related cancers
Propensity-matched cohort (12,000+ patients)
A propensity-matched cohort study of more than 12,000 patients with stage 1–3 cancer, presented at ASCO 2026, found that starting a GLP-1 receptor agonist after diagnosis was associated with a 31–50% reduction in progression to metastatic disease across seven obesity-related cancers, including breast, lung, colorectal, and liver cancer. In non-small cell lung cancer, progression occurred in 10% of GLP-1-treated patients versus 22% of controls.
Aon analysis: GLP-1 users show 40%+ reduction in major adverse cardiac events and lower cancer incidence in women
Actuarial claims analysis
Aon's longitudinal analysis of self-funded employer claims found GLP-1 users experienced a more than 40% reduction in major adverse cardiac events versus matched non-users, with female users showing a 47% reduction in cardiovascular hospitalizations, approximately 50% lower incidence of ovarian cancer, and 14% lower incidence of breast cancer.
SELECT trial: semaglutide reduced major cardiovascular events by 20% in adults with obesity without diabetes
Randomized controlled trial (17,604 participants)
In the landmark SELECT trial, semaglutide 2.4 mg weekly reduced the composite of cardiovascular death, nonfatal heart attack, and nonfatal stroke by 20% versus placebo in adults with established cardiovascular disease and overweight or obesity, without diabetes — the first demonstration that a weight-management medication improves hard cardiovascular outcomes.
Tumor GLP-1 receptor expression linked to 33% lower risk of death
Biomarker analysis
High tumor expression of the GLP-1 receptor was associated with a 33% lower risk of death compared with low expression, and a 45% lower risk in breast cancer specifically — an early signal of the biological mechanisms now under investigation in metabo-oncology.
GLP-1 use associated with 30% lower incidence of breast cancer in women without prior cancer
Observational cohort
Observational data presented alongside the ASCO 2026 metastasis findings suggest women taking GLP-1 receptor agonists without a prior cancer diagnosis had an approximately 30% lower incidence of breast cancer, raising the possibility of a preventive effect that is now the subject of prospective study.
SURMOUNT-1: tirzepatide produced up to 20.9% mean weight loss at 72 weeks
Randomized controlled trial
In SURMOUNT-1, adults with obesity (without diabetes) receiving weekly tirzepatide lost 15.0–20.9% of body weight at 72 weeks depending on dose, versus 3.1% with placebo — among the largest reductions recorded in a weight-management trial, with accompanying improvements in cardiometabolic risk factors.