The Definitive Peptide Research Reference Guide — Compound Review

SURMOUNT-1 Trial (Zepbound, 15 mg)

Tirzepatide Before & After

Clinical Trial Results Week by Week

Tirzepatide (Mounjaro/Zepbound) produces the largest weight loss of any approved medication in clinical trials — averaging 22.5% of body weight over 72 weeks in the SURMOUNT-1 trial at the highest dose.

Clinical Trial Results at a Glance

22.5%
Average Weight Loss (15 mg)
of body weight at 72 weeks (SURMOUNT-1)
21.4%
Average Weight Loss (10 mg)
of body weight at 72 weeks
91%
Responders ≥5%
of patients lost ≥5% body weight (15 mg)
63%
Responders ≥15%
of patients lost ≥15% body weight (15 mg)
57%
Responders ≥20%
of patients lost ≥20% body weight (15 mg)

Source: SURMOUNT-1 Trial (Zepbound, 15 mg) | Duration: 72 weeks | Individual results vary.

Important: Results shown are from clinical trials and represent averages. Individual results vary significantly based on dose, diet, exercise, metabolic health, and adherence. This page is for informational purposes only. Consult a qualified healthcare professional before use.

Week-by-Week Results Timeline

Weeks 1–4Dose Escalation

Starting dose: 2.5 mg/week. Appetite suppression begins within the first week. Weight loss during this phase is typically 1–4 lbs. GI side effects are most prominent during this initial phase.

Weeks 4–12Early Response

Dose increases from 2.5 mg to 5 mg/week. Average weight loss of 5–7% of body weight by week 12 in clinical trials. Appetite suppression becomes more pronounced. GI side effects typically begin to improve.

Weeks 12–28Accelerated Loss

Dose escalation continues (5 mg → 10 mg → 15 mg). Most users experience the fastest rate of weight loss during this phase. Average cumulative loss of 14–16% of body weight by week 28.

Weeks 28–52Sustained Loss

Maintenance dose of 10–15 mg/week reached. Weight loss continues at a steady rate. Average cumulative loss of 18–20% by week 52. Significant improvements in metabolic markers (blood glucose, lipids, blood pressure).

Weeks 52–72Maximum Results

Average total loss of 20.9–22.5% at week 72 in the SURMOUNT-1 trial (dose-dependent). Visceral fat reduction is particularly pronounced. Maintaining the dose is required to sustain results.

Factors That Affect Your Results

Dose

The 15 mg dose produces significantly more weight loss than the 5 mg or 10 mg doses. Tolerating dose escalation is key to maximizing results.

Diet Quality

SURMOUNT-1 included dietary counseling. Users who maintain a reduced-calorie diet achieve better outcomes.

Exercise

Resistance exercise helps preserve lean muscle mass. Tirzepatide produces greater fat loss relative to lean mass compared to semaglutide.

Metabolic Health

Patients with type 2 diabetes lose slightly less weight than non-diabetic patients, but still achieve clinically significant results.

Adherence

Consistent weekly dosing and completing the full dose escalation schedule are critical for maximum results.

Frequently Asked Questions

How much weight can I lose on tirzepatide?

Clinical trials show an average weight loss of 22.5% of body weight over 72 weeks with tirzepatide 15 mg (Zepbound/SURMOUNT-1). This is the largest weight loss ever recorded in a clinical trial for an approved obesity medication.

How quickly does tirzepatide work?

Most users notice appetite suppression within the first 1–2 weeks. Measurable weight loss (5–7%) typically occurs within 8–12 weeks. Maximum results are typically achieved at 52–72 weeks.

Is tirzepatide better than semaglutide for weight loss?

Yes. The SURMOUNT-5 head-to-head trial showed tirzepatide produced approximately 47% more weight loss than semaglutide (20.2% vs 13.7% at 72 weeks).

What happens when you stop tirzepatide?

Like semaglutide, most patients regain significant weight after stopping tirzepatide. The SURMOUNT-4 trial showed patients regained approximately 14% of body weight in the year after stopping.

Does tirzepatide preserve muscle mass?

Tirzepatide appears to produce a higher proportion of fat loss relative to lean mass compared to semaglutide, possibly due to its glucagon receptor agonism. Resistance exercise further helps preserve muscle.

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Medical Disclaimer: All content on this site is for educational and research purposes only. Research peptides are not FDA-approved for human use. Always consult a qualified healthcare professional before considering any peptide or supplement protocol. Nothing on this site constitutes medical advice, diagnosis, or treatment.