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Head-to-head evidence comparison — which supplement is right for you?
Tirzepatide wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
Shared outcomes (2)
Outcomes where both Retatrutide and Tirzepatide have evidence — compare verdict strength side-by-side.
Investigational — NO approved dose. Phase-2 trials used once-weekly subcutaneous injection with stepwise escalation (e.g. start 2 mg) up to 8-12 mg maintenance. There is no approved regimen; do not self-dose an unapproved drug.
once-weekly
Once-weekly subcutaneous injection (investigational only)
Once-weekly subcutaneous injection, started at 2.5 mg and escalated by 2.5 mg every 4 weeks to a maintenance dose of 5, 10, or 15 mg (per the prescribing physician and approved indication)
any
Once-weekly subcutaneous injection (Mounjaro / Zepbound)
Progressive over 24-48 weeks
By 24 weeks
By 24-36 weeks
Especially during dose escalation
Weeks to months
Months (dose-escalated over ~20 weeks)
Weeks to months
Mostly during titration
Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial.
N Engl J Med (2023) · Rct · n=338
Phase-2, double-blind, randomized, placebo-controlled trial in 338 adults with obesity (or overweight + a weight-related condition), once-weekly subcutaneous retatrutide 1-12 mg vs placebo for 48 weeks
Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA.
Lancet (2023) · Rct · n=281
Phase-2, double-blind, double-dummy, placebo- and active-comparator (1.5 mg dulaglutide)-controlled trial in 281 adults with type 2 diabetes, once-weekly retatrutide 0.5-12 mg over 36 weeks
Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial.
Nat Med (2024) · Rct · n=98
Phase-2a, randomized, double-blind, placebo-controlled MASLD substudy (n=98) of the obesity trial, in participants with ≥10% liver fat, once-weekly retatrutide 1-12 mg vs placebo
Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes.
N Engl J Med (2021) · Rct · n=1879
Open-label 40-week phase-3 head-to-head RCT (SURPASS-2) in 1879 patients with type 2 diabetes, tirzepatide 5/10/15 mg vs semaglutide 1 mg
Tirzepatide Once Weekly for the Treatment of Obesity.
N Engl J Med (2022) · Rct · n=2539
72-week phase-3 double-blind RCT (SURMOUNT-1) in 2539 adults with obesity (without diabetes), tirzepatide 5/10/15 mg vs placebo
Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.
N Engl J Med (2025) · Rct · n=751
Phase-3b open-label head-to-head RCT (SURMOUNT-5) in 751 adults with obesity but without diabetes, max-tolerated tirzepatide vs max-tolerated semaglutide
Tirzepatide has a higher evidence score (7.8/10 vs 5.5/10) and wins in 2 of 3 categories.
No known interactions between Retatrutide and Tirzepatide have been documented in our database. However, always consult a healthcare provider before combining supplements.