SUSTAIN-7: Semaglutide Against Dulaglutide
Last verified May 2026 · Phase 3b · Finished; published February 1, 2018 · NCT02648204 ↗
Head-to-head trials between drugs in the same class are rare because manufacturers have little incentive to run them and much to lose. SUSTAIN-7 is one of the exceptions, and matched dose levels rather than each drug's ceiling, which makes the comparison fair on its own terms. The result contributed to semaglutide displacing dulaglutide as the default weekly GLP-1 in diabetes, a commercial shift that later carried into the obesity market.
- Enrollment
- 1,201
- Duration
- 40 weeks on randomized treatment, then a five-week safety window closing at week 45
- Drug
- Semaglutide (vs dulaglutide once-weekly, head-to-head)
- Population
- Adults 18 and over whose type 2 diabetes ran at an HbA1c of 7.0% to 10.5%, holding a steady metformin dose and nothing else for at least 90 days. ⚠ Who was kept out shapes the safety table: nobody with previous pancreatitis, nobody with medullary thyroid cancer in themselves or the family, nobody with reduced kidney function, severe heart failure or advanced eye disease. Across the four arms, average HbA1c 8.2%, average weight 95.2 kg at a BMI near 33, and about 7.4 years since diagnosis.
Primary endpoint
How far three-month average blood sugar fell over 40 weeks, comparing the two drugs at matched dose tiers
Treatment arm
Semaglutide 0.5 mg: −1.5 percentage points (SE 0.06); semaglutide 1.0 mg: −1.8 percentage points (SE 0.06)
Comparator
Dulaglutide 0.75 mg: −1.1 percentage points (SE 0.05); dulaglutide 1.5 mg: −1.4 percentage points (SE 0.06)
Treatment difference: Low-dose comparison (sema 0.5 vs dula 0.75): ETD −0.40 pp (95% CI −0.55 to −0.25; P<0.0001). High-dose comparison (sema 1.0 vs dula 1.5): ETD −0.41 pp (95% CI −0.57 to −0.25; P<0.0001).
★ Semaglutide won at both tiers by about 0.4 points. The comparison people quote is the top pairing, because those were the highest approved diabetes doses for each drug at the time — which makes this a fair fight rather than one drug held back.
Secondary endpoints
| Endpoint | Treatment | Comparator | Difference |
|---|---|---|---|
| Weight lost at the lower dose of each drug Roughly double — 4.6 kg against 2.3 — from an average starting weight near 96 kg. | Semaglutide 0.5 mg: −4.6 kg (SE 0.28) | Dulaglutide 0.75 mg: −2.3 kg (SE 0.27) | ETD −2.26 kg (95% CI −3.02 to −1.51; P<0.0001 for superiority) |
| Weight lost at the higher dose of each drug ★ A 3.5 kg gap, and the finding that changed prescribing. When someone has both diabetes and excess weight, this row is why semaglutide became the default and dulaglutide did not. | Semaglutide 1.0 mg: −6.5 kg (SE 0.28) | Dulaglutide 1.5 mg: −3.0 kg (SE 0.27) | ETD −3.55 kg (95% CI −4.32 to −2.78; P<0.0001 for superiority) |
| How many reached the standard blood-sugar target Nearly four in five on the higher semaglutide dose, against two in three on the higher dulaglutide dose. | Semaglutide 0.5 mg: 68%; semaglutide 1.0 mg: 79% | Dulaglutide 0.75 mg: 52%; dulaglutide 1.5 mg: 67% | Odds ratio favored semaglutide at both tiers; P<0.0001 vs dulaglutide for both comparisons |
| How many reached the stricter target some specialists use ★ The gap widens as the bar rises: two thirds against fewer than half. The harder the target, the more the potency difference shows. | Semaglutide 0.5 mg: 47%; semaglutide 1.0 mg: 67% | Dulaglutide 0.75 mg: 30%; dulaglutide 1.5 mg: 45% | Odds ratio favored semaglutide at both tiers; P<0.0001 |
| Lost at least 5% of body weight 63% against 30% at the higher doses — twice as many. | Semaglutide 0.5 mg: 44%; semaglutide 1.0 mg: 63% | Dulaglutide 0.75 mg: 23%; dulaglutide 1.5 mg: 30% | Odds ratio favored semaglutide at both tiers; P<0.0001 |
| Lost at least a tenth of body weight ★ More than one in five on semaglutide against fewer than one in twelve. At the ambitious end the two drugs are not close. | Semaglutide 0.5 mg: 14%; semaglutide 1.0 mg: 22% | Dulaglutide 0.75 mg: 3%; dulaglutide 1.5 mg: 8% | Odds ratio favored semaglutide at both tiers; P<0.0001 |
| Blood sugar after an overnight fast Better on semaglutide at both tiers, though the difference is smaller than on the three-month average. | Semaglutide 0.5 mg: −2.2 mmol/L; semaglutide 1.0 mg: −2.8 mmol/L | Dulaglutide 0.75 mg: −1.9 mmol/L; dulaglutide 1.5 mg: −2.2 mmol/L | Reductions favored semaglutide at both tiers |
| Top blood-pressure number ⚠ Modest in every arm and broadly similar between drugs — a useful reminder that not everything separates just because the headline does. | Semaglutide 0.5 mg: −2.7 mmHg; semaglutide 1.0 mg: −5.0 mmHg | Dulaglutide 0.75 mg: −2.3 mmHg; dulaglutide 1.5 mg: −4.3 mmHg | Similar small reductions across arms; not a primary differentiator |
| Cholesterol and blood fats Small reductions on both, slightly larger on semaglutide. Nothing in this class is a substitute for a statin. | Total cholesterol, LDL, and triglycerides decreased modestly with semaglutide at both doses; HDL essentially unchanged | Comparable directional changes with dulaglutide at both doses; smaller magnitudes | Numerical differences favored semaglutide on triglycerides; lipid changes were not prespecified primary differentiators |
| Hitting target blood sugar without a dangerous low and without gaining weight ★ The most practically meaningful row, and the one formulary committees quote: 74% managed all three on the higher semaglutide dose against 53% on the higher dulaglutide dose. Older diabetes drugs delivered target blood sugar by trading away the other two. | Semaglutide 0.5 mg: 60%; semaglutide 1.0 mg: 74% | Dulaglutide 0.75 mg: 41%; dulaglutide 1.5 mg: 53% | Odds ratio favored semaglutide at both tiers; P<0.0001 |
Adverse events
| Event | Treatment rate | Comparator rate |
|---|---|---|
| Any stomach or bowel problem ★ The row that surprises people: at matched top doses the burden was effectively the same — 44% against 48%. The stronger drug was not the harder one to take. | Semaglutide 0.5 mg: 43% (129/301); semaglutide 1.0 mg: 44% (133/300) | Dulaglutide 0.75 mg: 33% (100/299); dulaglutide 1.5 mg: 48% (143/299) |
| Nausea Around 20 to 22% on semaglutide against 13 to 20% on dulaglutide, mostly mild to moderate and worst while the dose was climbing. | Semaglutide 0.5 mg: ≈20%; semaglutide 1.0 mg: ≈22% | Dulaglutide 0.75 mg: ≈13%; dulaglutide 1.5 mg: ≈20% |
| Diarrhea Much the same across all four arms. | Semaglutide 0.5 mg: ≈13%; semaglutide 1.0 mg: ≈15% | Dulaglutide 0.75 mg: ≈12%; dulaglutide 1.5 mg: ≈17% |
| Vomiting ⚠ Actually more common on the higher dulaglutide dose than on either semaglutide dose. | Semaglutide 0.5 mg: ≈7%; semaglutide 1.0 mg: ≈8% | Dulaglutide 0.75 mg: ≈5%; dulaglutide 1.5 mg: ≈11% |
| Severe or confirmed symptomatic low blood sugar Uncommon everywhere and similar between drugs. ⚠ That is a fact about the design as much as the drugs: everyone was on metformin alone. Add insulin or a sulfonylurea and this row would look very different for both. | Semaglutide 0.5 mg: 1.7%; semaglutide 1.0 mg: 0.7% | Dulaglutide 0.75 mg: 1.3%; dulaglutide 1.5 mg: 2.0% |
| Stopped the drug early over a side effect 10% against 7% at the higher doses, with stomach and bowel problems the reason in every arm. | Semaglutide 0.5 mg: 8%; semaglutide 1.0 mg: 10% | Dulaglutide 0.75 mg: 4%; dulaglutide 1.5 mg: 7% |
| Diabetic eye disease getting worse ⚠ A small numerical excess on semaglutide, echoing the clearer signal from the semaglutide cardiovascular trial. It is the basis for the eye precaution on the label, and the reason to have your eyes checked before starting if you already have retinopathy. | Semaglutide 0.5 mg: 1.3%; semaglutide 1.0 mg: 2.3% | Dulaglutide 0.75 mg: 1.0%; dulaglutide 1.5 mg: 0.7% |
| Deaths during the trial Six in all, split two on semaglutide and four on dulaglutide, none judged by investigators to be related to treatment. | Semaglutide 0.5 mg: 1 death; semaglutide 1.0 mg: 1 death | Dulaglutide 0.75 mg: 2 deaths; dulaglutide 1.5 mg: 2 deaths |
Clinical significance
For a weight-management reader this is background rather than a decision, since neither drug at these doses is what you would be prescribed for weight. Its value is in establishing the potency ordering within the class, which is the same ordering the obesity trials later confirmed. ⚠ These are diabetes doses in a diabetes population; the weight figures are not obesity-trial figures.
Who sells semaglutide, and for how much
This trial tested Semaglutide (vs dulaglutide once-weekly, head-to-head). Across the 556 sellers on this register, 283 publish a standing monthly cash price for compounded semaglutide, from $79 a month, with a median of $174.
⛔ None of those sellers was in this trial. A compounded preparation is not the product studied here: no agency has reviewed that specific preparation for safety, effectiveness or manufacturing quality, and its concentration is set by whichever pharmacy filled it. The result above is the strongest evidence available for semaglutide and it was generated on something else. Every seller, with its price record.
Frequently Asked Questions
References
- 1.Pratley RE, Aroda VR, Lingvay I, et al.; SUSTAIN 7 investigators. Semaglutide versus dulaglutide once weekly in patients with type 2 diabetes (SUSTAIN 7): a randomised, open-label, phase 3b trial. Lancet Diabetes Endocrinol. 2018. PMID: 29397376.
- 2.U.S. National Library of Medicine. Efficacy and Safety of Semaglutide Versus Dulaglutide as add-on to Metformin in Subjects With Type 2 Diabetes (SUSTAIN 7) — Study Record. ClinicalTrials.gov, NCT02648204. 2018. https://clinicaltrials.gov/study/NCT02648204
- 3.Frías JP, Davies MJ, Rosenstock J, et al.; SURPASS-2 Investigators. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med. 2021. PMID: 34170647.
- 4.U.S. Food and Drug Administration. Ozempic (semaglutide) injection — Original FDA Approval Letter and Prescribing Information (December 5, 2017). Drugs@FDA, NDA 209637. 2017. https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/209637lbl.pdf