Contents
Key findings
- 1The cardiovascular benefit is separate from the weight benefit — SELECT enrolled adults with cardiovascular disease and overweight but without diabetes, and found a 20% reduction in major adverse cardiovascular events.
- 2FLOW showed a 24% relative reduction in major kidney disease events in people with type 2 diabetes and chronic kidney disease.
- 3Tirzepatide reduced apnoea-hypopnoea index substantially in SURMOUNT-OSA and gained an FDA indication for obstructive sleep apnoea with obesity in December 2024.
- 4Heart failure with preserved ejection fraction improved on both drugs in dedicated trials (STEP-HFpEF, SUMMIT), a population with few effective options.
- 5These are six different benefits proven in six different populations. None of them generalises automatically to a healthy person taking the drug for appearance.
Evidence level
Each benefit described here rests on its own randomised controlled trial with a prespecified clinical endpoint, and several have led to distinct FDA indications. This is the strongest benefit evidence base of any peptide class.
Regulatory status
Semaglutide is FDA-approved for type 2 diabetes, chronic weight management and cardiovascular risk reduction; tirzepatide for type 2 diabetes, chronic weight management and obstructive sleep apnoea with obesity. Other uses described here are investigational or newly approved.
The weight-loss numbers made these drugs famous. The more interesting development is what has happened since: a series of separate trials, each testing a different organ system, each with its own prespecified endpoint. Most of them read out positive. This is what each one actually showed.
Why "beyond weight loss" is the right frame
A drug that only made people lighter would be a cosmetic drug. What has made the incretin class genuinely important in medicine is that it has been taken into cardiology, nephrology, hepatology and sleep medicine and tested properly in each — with hard or validated endpoints, in populations who were already sick.
That also means something specific for readers: each benefit belongs to the trial that produced it. Below, every claim is tagged with who was studied.
The cardiovascular benefit
Who was studied: 17,604 adults aged 45+, with established cardiovascular disease and BMI ≥27, and explicitly without diabetes.
What happened: over a mean 39.8 months, major adverse cardiovascular events — cardiovascular death, non-fatal heart attack, non-fatal stroke — fell by 20% versus placebo[1].
Study details: Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT)
- Study type
- Randomised, double-blind, placebo-controlled cardiovascular outcomes trial
- Population
- Adults ≥45 with established cardiovascular disease and BMI ≥27, without diabetes
- Sample size
- 17604
- Primary result
- Major adverse cardiovascular events reduced 20% (HR 0.80, 95% CI 0.72–0.90) over mean 39.8 months.
- Limitations
- Mechanism of benefit not fully explained by weight loss; population was predominantly male and white.
- Year
- 2023
- Source
- New England Journal of Medicine(link not yet independently re-verified)
This is the single most consequential result in the class, because it moved semaglutide from a metabolic drug to a cardiovascular one and produced a distinct FDA indication. One nuance worth carrying: the event curves separated earlier than weight loss alone would easily explain, which has driven interest in direct vascular and anti-inflammatory mechanisms. The trial was not designed to settle that, so it stays an open question.
The kidney benefit
Who was studied: 3,533 adults with type 2 diabetes and chronic kidney disease.
What happened: major kidney disease events — kidney failure, sustained large drops in eGFR, kidney or cardiovascular death — fell 24%[2]. The trial was stopped early because the benefit was clear.
Study details: Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes (FLOW)
- Study type
- Randomised, double-blind, placebo-controlled outcomes trial
- Population
- Adults with type 2 diabetes and chronic kidney disease
- Sample size
- 3533
- Primary result
- 24% relative reduction in major kidney disease events; trial stopped early for efficacy.
- Limitations
- Type 2 diabetes population only; does not establish benefit in non-diabetic kidney disease.
- Year
- 2024
- Source
- New England Journal of Medicine(link not yet independently re-verified)
Chronic kidney disease in diabetes has had few genuinely disease-modifying options, which is what makes this notable. It does not establish anything about kidney disease in people without diabetes.
The sleep apnoea benefit
Who was studied: 469 adults with moderate-to-severe obstructive sleep apnoea and obesity, in two trials — one in people using PAP therapy, one in people not using it.
What happened: substantial reductions in apnoea-hypopnoea index at 52 weeks versus placebo[3], leading to an FDA indication for tirzepatide in December 2024.
Study details: Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity (SURMOUNT-OSA)
- Study type
- Two randomised, double-blind, placebo-controlled phase 3 trials
- Population
- Adults with moderate-to-severe obstructive sleep apnoea and obesity, with and without PAP therapy
- Sample size
- 469
- Primary result
- Substantial reductions in apnoea-hypopnoea index versus placebo at 52 weeks.
- Limitations
- Did not compare directly against PAP therapy as an alternative.
- Year
- 2024
- Source
- New England Journal of Medicine(link not yet independently re-verified)
Worth stating plainly: the trials did not test tirzepatide against PAP therapy, so this is a new option rather than a demonstrated replacement for an existing one.
The heart failure benefit
Who was studied: 529 adults with heart failure with preserved ejection fraction (HFpEF) and BMI ≥30, without diabetes.
What happened: larger improvements in heart-failure symptoms, physical limitation scores and six-minute walk distance versus placebo at 52 weeks[4]. A companion trial of tirzepatide (SUMMIT) in a similar population reported improvements including fewer heart-failure events.
Study details: Semaglutide in Patients with Heart Failure with Preserved Ejection Fraction and Obesity (STEP-HFpEF)
- Study type
- Randomised, double-blind, placebo-controlled
- Population
- Adults with HFpEF and BMI ≥30, without diabetes
- Sample size
- 529
- Primary result
- Larger improvements in heart-failure symptoms and physical limitations, and in 6-minute walk distance, versus placebo at 52 weeks.
- Limitations
- Symptom and function endpoints rather than hospitalisation or mortality.
- Year
- 2023
- Source
- New England Journal of Medicine(link not yet independently re-verified)
HFpEF is a condition where very little has worked, so symptom and function gains matter. These are patient-reported and functional endpoints rather than mortality, which is the appropriate way to describe them.
The liver benefit
Who was studied: adults with biopsy-confirmed metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis.
What happened: in the ESSENCE interim analysis, more participants achieved resolution of steatohepatitis without worsening fibrosis, and more achieved fibrosis improvement, than on placebo at 72 weeks[5].
Study details: Semaglutide in Metabolic Dysfunction-Associated Steatohepatitis (ESSENCE)
- Study type
- Randomised, double-blind, placebo-controlled phase 3 (interim analysis)
- Population
- Adults with biopsy-confirmed MASH and fibrosis
- Sample size
- 800
- Primary result
- Higher rates of steatohepatitis resolution without worsening fibrosis, and of fibrosis improvement, versus placebo at 72 weeks.
- Limitations
- Interim analysis of an ongoing trial; histological endpoints.
- Year
- 2025
- Source
- New England Journal of Medicine(link not yet independently re-verified)
The benefit everyone forgets to mention
Weight reduction itself remains the anchor: 14.9% mean loss over 68 weeks in STEP 1[6], with tirzepatide higher still. Everything above happened in populations who were also losing weight, which is part of why disentangling mechanism is difficult — and part of why the benefits are real regardless.
What has not worked
Cognition. Observational data and animal work suggested GLP-1 agonists might protect against neurodegeneration, and two large phase 3 trials of oral semaglutide in early Alzheimer's disease tested it directly. In November 2025 the sponsor reported that neither met its primary endpoint[7].
Including this is not hedging. A benefit list that only contains successes tells you nothing about how reliable the list is.
Benefits at a glance
| Benefit | Drug | Population studied | Grade |
|---|---|---|---|
| Weight reduction | Both | Adults with overweight/obesity | Established evidenceSTEP 1, SURMOUNT-1 |
| Fewer cardiovascular events | Semaglutide | CVD + overweight, no diabetes | Established evidenceSELECT, n=17,604 |
| Slower kidney disease | Semaglutide | T2D + chronic kidney disease | Established evidenceFLOW, n=3,533 |
| Reduced sleep apnoea severity | Tirzepatide | Moderate-severe OSA + obesity | Established evidenceSURMOUNT-OSA; approved |
| Heart failure symptoms (HFpEF) | Both | HFpEF + obesity | Promising evidenceSTEP-HFpEF, SUMMIT |
| MASH resolution / fibrosis | Semaglutide | Biopsy-confirmed MASH | Promising evidenceESSENCE interim |
| Slowing Alzheimer's disease | Semaglutide (oral) | Early Alzheimer's disease | Unsupported evidenceevoke/evoke+ negative |
Two caveats that belong on every benefit list
Where to go next
- Peptide benefits: what the evidence supports — the whole category, ranked.
- GLP-1 peptides: established uses versus emerging research — the fuller analysis including safety and open questions.
- Semaglutide vs tirzepatide — head-to-head.
- Semaglutide profile · Tirzepatide profile
Frequently asked questions
- Do GLP-1 drugs protect the heart independently of weight loss?
- SELECT found the cardiovascular benefit appeared earlier than the weight curves would predict, which suggests mechanisms beyond weight alone. The trial was not designed to separate the two, so this remains an open question rather than a settled finding.
- Which GLP-1 benefits are FDA-approved indications?
- For semaglutide — type 2 diabetes, chronic weight management, and cardiovascular risk reduction. For tirzepatide — type 2 diabetes, chronic weight management, and obstructive sleep apnoea with obesity.
- Do these benefits apply if I am not in the trial population?
- Not automatically. Every benefit here was demonstrated in a specific group — people with cardiovascular disease, or kidney disease, or sleep apnoea. Extending a result beyond its trial population is an assumption, not a finding.
- Is there anything GLP-1 drugs have failed at?
- Yes. Two large phase 3 trials of oral semaglutide in early Alzheimer's disease reported in November 2025 that it did not slow cognitive decline.
References
Numbered in order of first use. Study type is shown for every source; see our methodology for how we rank evidence.
- 1.
Lincoff AM, Brown-Frandsen K, Colhoun HM, et al.. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT) New England Journal of Medicine, 2023.
Randomized controlled trialAdults ≥45 with established cardiovascular disease and BMI ≥27, without diabetesn = 17604
Result: Major adverse cardiovascular events reduced 20% (HR 0.80, 95% CI 0.72–0.90) over mean 39.8 months.
Limitations: Mechanism of benefit not fully explained by weight loss; population was predominantly male and white.
↑ back to text - 2.
Perkovic V, Tuttle KR, Rossing P, et al.. Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes (FLOW) New England Journal of Medicine, 2024.
Randomized controlled trialAdults with type 2 diabetes and chronic kidney diseasen = 3533
Result: 24% relative reduction in major kidney disease events; trial stopped early for efficacy.
Limitations: Type 2 diabetes population only; does not establish benefit in non-diabetic kidney disease.
↑ back to text - 3.
Malhotra A, Grunstein RR, Fietze I, et al.. Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity (SURMOUNT-OSA) New England Journal of Medicine, 2024.
Randomized controlled trialAdults with moderate-to-severe obstructive sleep apnoea and obesity, with and without PAP therapyn = 469
Result: Substantial reductions in apnoea-hypopnoea index versus placebo at 52 weeks.
Limitations: Did not compare directly against PAP therapy as an alternative.
↑ back to text - 4.
Kosiborod MN, Abildstrøm SZ, Borlaug BA, et al.. Semaglutide in Patients with Heart Failure with Preserved Ejection Fraction and Obesity (STEP-HFpEF) New England Journal of Medicine, 2023.
Randomized controlled trialAdults with HFpEF and BMI ≥30, without diabetesn = 529
Result: Larger improvements in heart-failure symptoms and physical limitations, and in 6-minute walk distance, versus placebo at 52 weeks.
Limitations: Symptom and function endpoints rather than hospitalisation or mortality.
↑ back to text - 5.
Sanyal AJ, Newsome PN, Kliers I, et al.. Semaglutide in Metabolic Dysfunction-Associated Steatohepatitis (ESSENCE) New England Journal of Medicine, 2025.
Randomized controlled trialAdults with biopsy-confirmed MASH and fibrosisn = 800
Result: Higher rates of steatohepatitis resolution without worsening fibrosis, and of fibrosis improvement, versus placebo at 72 weeks.
Limitations: Interim analysis of an ongoing trial; histological endpoints.
↑ back to text - 6.
Wilding JPH, Batterham RL, Calanna S, et al.. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1) New England Journal of Medicine, 2021.
Randomized controlled trialAdults with overweight or obesity without diabetesn = 1961
Result: Mean weight change −14.9% vs −2.4% placebo at 68 weeks.
↑ back to text - 7.
Novo Nordisk announces results from evoke and evoke+ trials of oral semaglutide in early Alzheimer's disease Novo Nordisk (company announcement), 2025.
Source
Result: Trials did not meet the primary endpoint of slowing progression on CDR-SB.
Limitations: Company announcement; full publication pending at our last check.
↑ back to text - 8.
FDA's concerns with unapproved GLP-1 drugs used for weight loss U.S. Food and Drug Administration, 2025.
Regulatory source
Result: Describes shortage resolution, adverse events reported with compounded products, and counterfeit products.
↑ back to text
Review status: Editorially reviewed against primary sources. This article was fact-checked against the primary sources listed in the references by our editorial team, and it has not been reviewed by a licensed clinician. It is educational content, not medical advice. Read our editorial policy and methodology. Spotted an error? Tell us.
