Semaglutide vs. tirzepatide for type 2 diabetes: A1C, heart, kidneys

In diabetes care, semaglutide is sold as Ozempic, a weekly shot of 0.25 mg rising to as much as 2 mg, and as daily tablets. The tablets are Rybelsus (3, 7 or 14 mg) and the newer Ozempic tablets (1.5, 4 or 9 mg), and the two are not interchangeable milligram for milligram. Tirzepatide is Mounjaro, a weekly shot from 2.5 mg to 15 mg. It is also approved for children aged 10 and older, with a 10 mg ceiling.

On glucose, both drugs raise insulin output only when blood sugar is high and lower glucagon, the hormone that tells the liver to release sugar. Tirzepatide adds a second receptor, GIP, which is thought to add to the glucose and appetite effect. Both labels now list lowering major cardiovascular events in adults with type 2 diabetes. Ozempic also lists slowing kidney decline in people with type 2 diabetes and chronic kidney disease.

SURPASS-2 (Frías et al., NEJM 2021) is the direct comparison. It randomized 1,879 adults on metformin, with a starting HbA1c of 8.28%, to tirzepatide 5, 10 or 15 mg or semaglutide 1 mg for 40 weeks. HbA1c fell by 2.01, 2.24 and 2.30 points on tirzepatide and 1.86 points on semaglutide. Tirzepatide also cut weight by 1.9 to 5.5 kg more. Semaglutide was capped at 1 mg, half of Ozempic's current 2 mg maximum, and the trial was open-label and funded by Lilly. A 2026 meta-analysis in Clinical Obesity that included people with diabetes found HbA1c 0.29 points lower with tirzepatide overall.

Heart and kidney outcomes come from separate trials. For semaglutide, SUSTAIN-6 found a 26% lower rate of major cardiovascular events than placebo. SOUL found 14% fewer with oral semaglutide. FLOW found a 24% lower risk of kidney failure, major eGFR loss or death from kidney or heart causes in people with chronic kidney disease. For tirzepatide, SURPASS-CVOT followed 13,299 people with diabetes and heart disease for a median of about 4 years. Events occurred in 12.2% on tirzepatide and 13.1% on dulaglutide (hazard ratio 0.92). That proved noninferiority but not superiority, and it led to Mounjaro's cardiovascular indication on August 28, 2026. No outcomes trial has pitted tirzepatide against semaglutide directly.

Stomach effects lead for both. In SURPASS-2, nausea affected 17% to 22% of people on tirzepatide and 18% on semaglutide. Diarrhea affected 13% to 16% versus 12%, and vomiting 6% to 10% versus 8%. Most cases were mild to moderate.

Low blood sugar is the diabetes-specific risk. On metformin alone it was rare in SURPASS-2 (0.2% to 1.7% on tirzepatide, 0.4% on semaglutide). The labels warn the risk rises with insulin or a sulfonylurea, and those doses are often cut when either drug starts. Serious adverse events were reported in 5% to 7% on tirzepatide and 3% on semaglutide.

Eyes: SUSTAIN-6 saw more diabetic retinopathy complications with semaglutide (hazard ratio 1.76). Both labels advise monitoring if you already have retinopathy. Both also warn about pancreatitis, gallbladder disease and kidney injury from dehydration, and carry the rodent thyroid C-cell tumor boxed warning.

Tirzepatide (Mounjaro) may suit you if your HbA1c is well above target and weight loss would also help, since it beat semaglutide 1 mg on both in SURPASS-2. It also fits a child aged 10 or older who needs an injectable option, where Mounjaro is approved.

Semaglutide may suit you if you have chronic kidney disease, because FLOW is the only kidney-outcomes trial of the two and it backs Ozempic's kidney indication. It is also the choice if you prefer a daily tablet to a weekly injection.

Both are reasonable if heart protection is the priority. Each now carries a cardiovascular indication, from different trial designs.

Neither is right with a personal or family history of medullary thyroid carcinoma or MEN2. If you use insulin or a sulfonylurea, plan the dose changes with your prescriber before you start, not after a low. Compounded versions are not FDA-approved and carry none of these indications. If cost decides it, compounded semaglutide at Temi starts at $59.99 per 7.5 mg vial plus a $39 service fee [usetemi.com/medications/compounded-semaglutide-injectable, verified Sep 28, 2026].