Semaglutide and tirzepatide each hold two separate marketing authorizations. One is for glycemic control in type 2 diabetes and one is for chronic weight management, and each carries its own brand name, its own labeled dose range and its own body of trial evidence. A compounded vial arrives with none of that attached, which is why the distinction matters more to buyers on the semaglutide board than it does to anyone filling a branded prescription.
The dose ceilings are not the same drug on both sides
For semaglutide the two ladders end in different places. SUSTAIN FORTE randomized 961 adults with inadequately controlled type 2 diabetes to once-weekly semaglutide at 2.0 mg or 1.0 mg for 40 weeks, the trial that established the higher of the two diabetes doses.[1]Weight management runs to 2.4 mg, a rung above that ceiling.
For tirzepatide the milligram figures coincide — 5, 10 and 15 — and the difference is the escalation schedule and the indication rather than the number on the pen. Either way, a prescriber choosing between them is choosing a protocol, not merely a molecule, and the climb through it is where the two diverge in practice.
The diabetes trials were asking about glucose
SURPASS-2 assigned 1,879 patients with type 2 diabetes to tirzepatide at 5 mg, 10 mg or 15 mg or to semaglutide at 1 mg for 40 weeks. The primary endpoint was change in glycated hemoglobin, which fell by 2.01, 2.24 and 2.30 percentage points on tirzepatide against 1.86 on semaglutide, with mean baseline glycated hemoglobin of 8.28%.[2]
Weight came second in that design and was reported in kilograms rather than percentages: treatment differences against semaglutide of 1.9, 3.6 and 5.5 kg.[2] A kilogram figure from a glucose trial and a percentage from an obesity trial cannot be laid side by side, which is the most common misreading of this literature and the reason the molecule comparison treats that trial carefully.
What a higher diabetes dose actually bought
SUSTAIN FORTE is unusually clean on this point because it changed one thing. Going from 1.0 mg to 2.0 mg moved glycated hemoglobin from a 1.9 to a 2.2 percentage-point reduction. It moved body weight from −6.0 kg to −6.9 kg, an estimated difference of 0.93 kg.[1]
Roughly a kilogram, over 40 weeks, for doubling the dose. Dose escalation inside the diabetes indication is built to chase glucose, and the weight effect that comes with it is real but modest. That is a different engineering goal from the obesity ladder, which was designed around percentage of body weight from the start.
The population explains part of the gap as well. SUSTAIN FORTE enrolled people whose glycated hemoglobin sat between 8.0% and 10.0% on metformin, with a mean body-mass index of 34.6.[1] They were recruited because their glucose was not controlled, not because they wanted to lose weight, and the endpoints follow from that.
The obesity trials changed the question
STEP 2 makes the split visible inside a single protocol. It randomized 1,210 adults with overweight or obesity and type 2 diabetes into three arms: semaglutide 2.4 mg, semaglutide 1.0 mg, or placebo, for 68 weeks. The trial describes that middle arm as the dose approved for diabetes treatment, and percentage change in body weight was a coprimary endpoint.[3]
Estimated change on 2.4 mg was −9.6% against −3.4% on placebo, and a reduction of 5% or more was reached by 68.8% against 28.5%, an odds ratio of 4.88 (95% CI, 3.58 to 6.64).[3] The endpoint, the ladder and the comparator all belong to weight management, even though every participant had diabetes.
The same product does less in people with diabetes
That is the finding buyers are least often told. SURMOUNT-2 gave tirzepatide 10 mg and 15 mg to 938 adults with a body-mass index of 27 or higher and glycated hemoglobin between 7% and 10% for 72 weeks, producing −12.8% and −14.7% against −3.2% on placebo.[4]The same 15 mg dose over the same 72 weeks reached −20.9% in adults without diabetes.[5]
Semaglutide shows the same direction and a similar size of gap, as the semaglutide figures set out. A person with type 2 diabetes reading a marketing page built on the non-diabetes trial is reading a number that was not measured in anyone like them.
The gap does not make treatment less worth having. SURMOUNT-2 still moved 79% to 83% of treated participants past a 5% reduction, against 32% on placebo.[4] It means the expectation being set at intake should come from the trial that enrolled people with the same diagnosis, and telehealth intake forms that ask about diabetes rarely change the number on the landing page that follows.
Where the outcome evidence sits
The oldest and largest trials in this class were run in diabetes, at diabetes doses, for cardiovascular endpoints. SUSTAIN-6 randomized 3,297 patients with type 2 diabetes to semaglutide 0.5 mg or 1.0 mg or placebo over 104 weeks.[6] Those doses are below the obesity ladder entirely, which is worth holding in mind whenever a cardiovascular claim is attached to a weight-management product — the detail is in the outcome-trial article.
What a vial with no indication inherits
None of this transfers automatically to compounded product. A compounded preparation is made against a prescription and is not FDA-approved for either indication, so neither dose ceiling constrains it and neither trial describes it. What a seller is really choosing is which ladder to copy, and that choice is often invisible on the checkout page — see what compounding does and does not change.
Two questions settle most of it before money moves. Which milligram schedule does the prescriber intend, and does the monthly price hold as that number climbs. Sellers that answer the second one plainly are listed on the flat-dose board, and how any of these figures gets established before publication is described in the methodology.