Tirzepatide

A dual incretin agonist with the strongest average weight-loss among currently approved peptide medicines. SURMOUNT and SURPASS programs are the evidence base. Same incretin-class cautions as GLP-1 monotherapy, plus the need to treat it as a prescription drug, not a wellness peptide.

Dual agonist at GIP and GLP-1 receptors. The GIP arm appears to add insulinotropic and adipose effects on top of classic GLP-1 pharmacology, which is the leading explanation for larger average weight-loss in head-to-head work versus semaglutide.

SURPASS (diabetes) and SURMOUNT (obesity) are large, multi-trial programs. SURMOUNT-1 showed double-digit mean weight loss at the higher doses. Head-to-head data versus semaglutide generally favor tirzepatide on weight, with a similar GI adverse-event pattern.

FDA-approved as Mounjaro (type 2 diabetes) and Zepbound (weight management, and later OSA in adults with obesity). Prescription only.

Prescription of Mounjaro (type 2 diabetes) or Zepbound (weight management; also OSA in adults with obesity). Same compounding rule as other approved GLP-1/GIP products: a shortage workaround is not a standing generic.

Same four pathways as the Sourcing guide.

Mounjaro follows diabetes prior-auth pathways. Zepbound for obesity is commercial-plan dependent. Under the Medicare GLP-1 Bridge (1 July 2026–31 December 2027), Zepbound KwikPen is covered at $50/month for eligible Part D members; single-dose Zepbound vials and pens are not in that program. Confirm the device, not just the molecule.

Same underground as semaglutide: compounded dual-agonist vials, research-chemical listings, and counterfeit pens. Dual-agonist compounding is not equivalent to Zepbound.

Strand does not list vendors. See the grey market.

GI effects dominate. Same MTC/MEN2 contraindication as GLP-1 agonists. Hypoglycemia risk rises when combined with insulin or sulfonylureas. Gallbladder events and a pancreatitis caution apply. Not for pregnancy.

• GI effects dominate; hypoglycemia risk rises with insulin or sulfonylureas.
• Same MTC/MEN2 contraindication as GLP-1 agonists.
• Gallbladder events and a pancreatitis caution apply. Not for pregnancy.
• Device-specific coverage (KwikPen vs vial) is a real access constraint.

• SURMOUNT-1 · 2022 · N Engl J Med

  Jastreboff et al. Tirzepatide once weekly for the treatment of obesity. PMID 35658024.

• SURPASS-2 · 2021 · N Engl J Med

  Frías et al. Tirzepatide versus semaglutide once weekly in type 2 diabetes. PMID 34170647.

• FDA labels

  Prescribing information for Mounjaro and Zepbound.