GLP-1 benefits and uses

What sources report

Each finding below names its evidence: an FDA label, or a randomized trial with its design or phase, size and length. Uses that are not approved are marked as such, and retatrutide is not an approved drug for any use.²³

Blood sugar in type 2 diabetes

• Ozempic label: in a 30-week trial of semaglutide alone, HbA1c fell 1.4 points on 0.5 mg and 1.6 on 1 mg.⁴ It fell 0.1 on placebo.⁴
• SURPASS-2 (phase 3, 1,879 adults on metformin, 40 weeks): HbA1c fell 2.01 to 2.30 points on tirzepatide 5 to 15 mg.⁵⁹ It fell 1.86 on semaglutide 1 mg.⁵
• TRANSCEND-T2D-1 (phase 3, 537 adults, 40 weeks): HbA1c fell 1.69 to 1.94 points on retatrutide, against 0.81 on placebo.⁶ No severe low blood sugar was reported.⁶

Heart and blood vessels

• SELECT (randomized, placebo-controlled): 17,604 adults with heart disease and overweight or obesity but no diabetes, followed for a mean of 39.8 months.¹ The hazard ratio for a major cardiovascular event was 0.80 with semaglutide 2.4 mg.¹
• SUSTAIN-6 (randomized, placebo-controlled, 3,297 people with type 2 diabetes, 104 weeks): major cardiovascular events affected 6.6% on semaglutide against 8.9% on placebo.⁷ Nonfatal stroke affected 1.6% against 2.7%.⁷
• SURPASS-CVOT (double-blind, against dulaglutide): 13,299 people with type 2 diabetes and atherosclerotic cardiovascular disease, followed for a median of 210 weeks.⁸⁹ Major cardiovascular events occurred in 12.2% on tirzepatide against 13.1% on dulaglutide.⁸ Tirzepatide was noninferior but not shown to be better.⁸ In August 2026 the Mounjaro label added heart risk reduction for high-risk adults with type 2 diabetes.⁹
• SUMMIT (randomized, placebo-controlled): 731 patients with obesity and heart failure with preserved ejection fraction, median 104 weeks.¹⁰ Cardiovascular death or worsening heart failure occurred in 9.9% on tirzepatide against 15.3% on placebo.¹⁰ Heart failure is not among Zepbound's approved uses.¹¹

Kidneys

• FLOW (randomized, placebo-controlled): 3,533 people with type 2 diabetes and chronic kidney disease, median 3.4 years.² The trial stopped early after a planned interim analysis.² The hazard ratio for the main kidney outcome was 0.76 on semaglutide 1 mg.² The Ozempic label now covers lowering the risk of kidney decline, end-stage kidney disease and cardiovascular death in this group.⁴

Liver

• ESSENCE (phase 3 interim analysis): 800 patients with MASH and moderate to advanced fibrosis, 72 weeks.¹² Steatohepatitis resolved without worsening fibrosis in 62.9% on semaglutide 2.4 mg, against 34.3% on placebo.¹² Fibrosis improved without worsening steatohepatitis in 36.8%, against 22.4%.¹² Wegovy holds an accelerated approval for this use, and continued approval may depend on a confirmatory trial.¹³
• SYNERGY-NASH (phase 2, 190 participants, 52 weeks): MASH resolved without worsening fibrosis in 44% to 62% on tirzepatide 5 to 15 mg, against 10% on placebo.¹⁴ MASH is not an approved use of Mounjaro or Zepbound.⁹¹¹
• Retatrutide phase 2a (98 participants with fatty liver disease): at 24 weeks, liver fat fell 82.4% on 12 mg, against a 0.3% rise on placebo.¹⁵

Sleep apnea

• SURMOUNT-OSA (two phase 3 trials, 52 weeks): 469 adults with obesity and moderate to severe obstructive sleep apnea.³¹¹ Breathing interruptions fell by 25.3 and 29.3 events per hour on tirzepatide, against 5.3 and 5.5 on placebo.³ Zepbound is approved for this use.¹¹
• TRIUMPH-1-OSA (phase 3, 80 weeks): adults with moderate to severe sleep apnea, a BMI of 27 or more and no diabetes.¹⁶ Events fell by 22.9 to 34.3 per hour across retatrutide doses, against 9.9 on placebo.¹⁶

Diabetes prevention

• SURMOUNT-1 three-year analysis (phase 3, 176 weeks): 1,032 adults with obesity and prediabetes.¹⁷ Type 2 diabetes was diagnosed in 1.3% on tirzepatide, against 13.3% on placebo.¹⁷ Diabetes prevention is not among Zepbound's approved uses.¹¹

Knee pain

• TRIUMPH-1 subgroup (phase 3, 80 weeks): 574 adults with obesity and knee osteoarthritis.¹⁸ Knee pain scores (WOMAC) fell 3.2 to 3.6 points on retatrutide, against 1.9 points on placebo.¹⁸

Weight

In STEP 1 and SURMOUNT-1, average loss at 68 to 72 weeks was about 15% to 21% on the approved doses.¹⁹²⁴ Placebo groups lost 2% to 3%.¹⁹²⁴ Trial-by-trial results, and what happened after people stopped, are on GLP-1 and weight loss.

Limits of the evidence

Trial results are group averages under medical supervision, and individual responses vary. A heart benefit of retatrutide has not been shown.²⁰ TRIUMPH-3, in adults with severe obesity and established cardiovascular disease, is so far a company report: Lilly says detailed results will go to medical meetings and peer-reviewed journals.²⁰ Major cardiovascular events were fewer than expected in both the retatrutide and placebo groups.²⁰ Lilly's five-part measure (death from any cause, heart attack, stroke, heart failure event or coronary revascularization) counted 44 events on retatrutide 9 and 12 mg combined against 52 on placebo.²⁰ The hazard ratio was 0.82, with a 95% confidence interval of 0.55 to 1.22 that includes no effect.²⁰ The same trials that show these benefits also report frequent side effects, listed on GLP-1 side effects.

Read next

The class overview is What is GLP-1?, and the label schedules are on GLP-1 dosage. Compound and brand pages carry more detail: semaglutide benefits, tirzepatide benefits, Ozempic benefits, Wegovy benefits, Mounjaro benefits and Zepbound benefits.