Retatrutide vs Tirzepatide
Written by Aaron CuhaReviewed Sep 2026
The short answer
A drug still in testing that hits three switches, against the approved drug that hits two.
- Retatrutide people
- 1,345
- Retatrutide nulls
- 0
- Tirzepatide people
- 22,802
- Tirzepatide nulls
- 0
Dose
Trial titration, not approved: 1, 2, 4, 8 and 12 mg
1, 2, 4, 8 and 12 mg
Doses used across the retatrutide trials, in mg. Not an approved ladder.
Dose
Approved titration: 2.5, 5, 7.5, 10, 12.5 and 15 mg
2.5, 5, 7.5, 10, 12.5 and 15 mg
The approved tirzepatide ladder, in mg.
First-hand reports are counted on each profile and never added together. This page sets two published records side by side. It does not pick a winner.
Column A
RetatrutideRetatrutide (triple GLP-1/GIP/glucagon agonist)
A weekly shot that is still being tested. It works on three hunger and blood sugar signals. It has led to the most weight loss of any drug in studies so far.
Column B
TirzepatideTirzepatide (dual GIP/GLP-1 receptor agonist)
A once a week shot that works on two hunger and blood sugar signals, GIP and GLP-1. In studies it led to more weight loss and lower blood sugar than drugs that work on GLP-1 alone.
Side by side, on the facts we can check
| What we compare | Retatrutide | Tirzepatide |
|---|---|---|
| Category | Metabolic | Metabolic |
| FDA status | Investigational, not FDA-approved. Results from TRIUMPH-1, a final-stage study, came out in May 2026. The maker expects to ask the FDA for approval in late 2026 | FDA-approved (Mounjaro for type 2 diabetes and, from August 2026, to lower the risk of major heart and blood vessel problems in people with type 2 diabetes; Zepbound for weight management and sleep apnea) |
| Half-life | ~6 days | ~5 days |
| Molecular weight | ~4,731 Da | 4,813.5 Da |
| How it works | It switches on three receptors: GLP-1, GIP and glucagon. The glucagon part makes the body burn more energy and burn more fat in the liver. The other two turn down hunger and help the body release insulin. | It switches on two receptors at once, GIP and GLP-1. Both answer gut hormones after a meal. Together they make the body release insulin when blood sugar is high, hold back glucagon, slow how fast the stomach empties and turn down hunger. The GIP part is thought to add its own effect on how the body handles sugar and fat. |
| Studies in people | 11 | 11 |
| Evidence | Strong: 5 completed trials, 1,345 people given it | Strong: 9 completed trials, 22,802 people given it |
| Legal status, US | Investigational, not approved for any use | FDA-approved, prescription only |
Frequently asked questions
What is the difference between Retatrutide and Tirzepatide?
Retatrutide: A weekly shot that is still being tested. It works on three hunger and blood sugar signals. It has led to the most weight loss of any drug in studies so far. Tirzepatide: A once a week shot that works on two hunger and blood sugar signals, GIP and GLP-1. In studies it led to more weight loss and lower blood sugar than drugs that work on GLP-1 alone.
Which has stronger research evidence, Retatrutide or Tirzepatide?
Each compound gets a band worked out from facts we counted, with the math shown. Retatrutide is Strong (5 completed trials, 1,345 people given it). Tirzepatide is Strong (9 completed trials, 22,802 people given it). That counts how much has been done in people. It does not rate whether either one works, and neither one is called the winner.
Are Retatrutide and Tirzepatide FDA-approved?
Retatrutide: Investigational, not FDA-approved. Results from TRIUMPH-1, a final-stage study, came out in May 2026. The maker expects to ask the FDA for approval in late 2026. Tirzepatide: FDA-approved (Mounjaro for type 2 diabetes and, from August 2026, to lower the risk of major heart and blood vessel problems in people with type 2 diabetes; Zepbound for weight management and sleep apnea).
Related posts
Blog articles that cover Retatrutide or Tirzepatide, newest first.
- Dispatch / Sep 27, 2026 / 8 minDispatch 001: Five Retatrutide Phase 3 Trials Have Finished And None Has Posted Results
- Metabolic / Sep 27, 2026 / 8 minTesofensine Is Not a Peptide: What It Is, the Trials, and the Heart-Rate Issue
- Metabolic / Sep 27, 2026 / 10 minOral GLP-1s in 2026: Wegovy Pill vs Foundayo (Orforglipron) vs Rybelsus, and What Is Coming
- Metabolic / Sep 27, 2026 / 9 minMariTide (Maridebart Cafraglutide): The Once-Monthly GLP-1 Agonist and GIP Blocker, Explained
Reviewed Sep 2026. This page puts two published records side by side. It is for learning, and it is not medical advice. When this site shows a dose, it is the dose a trial or a clinic actually used, or what people say they did, with the source attached. None of it tells you what to take.