Compounded tirzepatide vs. compounded semaglutide

Semaglutide copies GLP-1, a gut hormone that slows stomach emptying, releases insulin when glucose is high and reduces appetite. Tirzepatide activates the GLP-1 receptor and a second one, GIP, which is why it is described as a dual agonist. The doses are on different scales: semaglutide's weight-management pen tops out at 2.4 mg a week (7.2 mg for Wegovy HD), while tirzepatide runs from 2.5 mg to 15 mg a week.

As compounded products they look alike. Both arrive as vials with a separate syringe, both are injected under the skin once a week, and both are escalated over months. Neither is FDA-approved, and in each case the label on the vial, not a device, tells you the concentration. At Temi, the listed semaglutide vial is 5 mg/mL and the tirzepatide vial 17 mg/mL (usetemi.com, checked 28 Sep 2026), so the same number of units delivers very different amounts of drug.

The only direct comparison used the brands, not compounded products. SURMOUNT-5 (NEJM 2025) randomised 751 adults with obesity and without type 2 diabetes to the highest tolerated dose of tirzepatide (10 or 15 mg) or semaglutide (1.7 or 2.4 mg) for 72 weeks. Mean weight change was −20.2% with tirzepatide and −13.7% with semaglutide; waist circumference fell 18.4 cm against 13.0 cm. The trial was open-label, meaning participants knew which drug they were taking.

Cardiovascular evidence points the other way for people without diabetes. SELECT showed semaglutide 2.4 mg lowered major cardiovascular events by 20% in adults with established heart disease and overweight or obesity. Tirzepatide's outcome trial, SURPASS-CVOT, was run in type 2 diabetes against another GLP-1 drug, dulaglutide: events occurred in 12.2% against 13.1%, which met non-inferiority but not superiority.

None of these trials used a compounded preparation, so they tell you about the molecules, not about any pharmacy's vial.

The two molecules share a class profile. In SURMOUNT-5, the most common adverse events with both were gastrointestinal, mostly mild to moderate and concentrated during dose escalation. Both labels list nausea, diarrhoea, vomiting, constipation and abdominal pain among the common reactions, and tirzepatide's also names indigestion, injection-site reactions and fatigue. Both carry warnings for pancreatitis, gallbladder disease and kidney injury from dehydration, and the rodent thyroid C-cell boxed warning applies to both.

What differs in practice is arithmetic. Because the tirzepatide vial is more concentrated, a small misread on the syringe moves more drug: at 17 mg/mL, five extra units is about 0.85 mg of tirzepatide; at 5 mg/mL, it is 0.25 mg of semaglutide. Nobody can predict in advance which molecule a given person will tolerate better.

Tirzepatide suits people whose main goal is weight reduction, who have no cardiovascular reason to prefer semaglutide, and who can absorb the higher monthly cost.

Semaglutide suits people with established heart disease, where SELECT supports it; people who want the lowest monthly cost; and people who have already done well on it.

Cost separates them more than the per-vial price suggests. Using Temi's listed prices (usetemi.com, checked 28 Sep 2026), semaglutide works out at $8.00 per mg and tirzepatide at $11.50 to $12.35 per mg. Four weeks at 2.4 mg of semaglutide is 9.6 mg, about $77 of drug; four weeks at 10 mg of tirzepatide is 40 mg, about $460. Both figures exclude the $39 service fee and any vial discarded at 28 days, and your dose may differ.

Neither is appropriate with a personal or family history of medullary thyroid carcinoma or MEN 2.