Tirzepatide

Overview

Tirzepatide activates both the GLP-1 and the GIP receptors. In the head-to-head SURMOUNT-5 Phase 3b RCT (published in the New England Journal of Medicine, 2025), tirzepatide produced greater average weight loss than semaglutide over 72 weeks (approximately 20.2% vs 13.7% reduction in body weight). The dual mechanism is hypothesized to influence fat oxidation, but lean-mass loss can still occur with rapid weight reduction, so protein intake and resistance training are commonly emphasized. Like semaglutide, this is a prescription medication that must be prescribed and supervised by a licensed clinician; the information here is educational only.

Commonly Reported Uses

These are uses commonly discussed or marketed by users and vendors — not a list of proven or approved benefits, and not a recommendation.

• Chronic weight management (FDA-approved as Zepbound)
• Type 2 diabetes glycemic control (FDA-approved as Mounjaro)
• Discussed for body-recomposition / 'cutting' goals — supervised, off-label discussions only

What to Track

Data points you and your clinician might monitor. For observation only — not a diagnostic protocol.

• Body weight — daily smart-scale trend with 7-day rolling average
• Body composition — InBody/DEXA skeletal muscle mass and body-fat mass every 2–4 weeks; track lean-mass preservation closely
• Nutrition — MyFitnessPal protein intake and caloric adherence
• Labs — HbA1c, fasting glucose, fasting insulin, lipid panel at baseline and follow-up
• Whoop — resting heart rate, recovery, sleep quality
• Subjective — appetite, GI tolerance, energy

Sources & References

1. [1]Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5) — PubMed
2. [2]SURMOUNT-5: greater loss of weight and waist circumference with tirzepatide — American College of Cardiology
3. [3]Lilly press release — tirzepatide superior to semaglutide (20.2% vs 13.7%)
4. [4]FDA — Zepbound (tirzepatide) approval information