Orforglipron vs Retatrutide
One approved pill and one investigational injection, pulling in opposite directions: an oral small molecule chasing access, and a triple agonist chasing maximum effect.
Short answer
In their pivotal trials, retatrutide led to 24.2% at 48 weeks in a published Phase 2 obesity trial, and orforglipron to 11.2% at 72 weeks in ATTAIN-1. Those figures come from separate trials, not a head-to-head study. Only orforglipron is FDA-approved; retatrutide is still investigational in the US.
Orforglipron
~11% in ATTAIN-1; a scalable oral pill whose appeal is access, not peak efficacy. FDA-approved for weight management (Foundayo, 2026) — the type-2 diabetes indication is still under review.
Full Orforglipron evidence reviewRetatrutide
Up to ~28% at 80 weeks in its Phase 3 topline — the largest figure reported for any incretin, but not approved anywhere.
Full Retatrutide evidence reviewOrforglipron vs Retatrutide: head to head
- FDA status / approved use
Orforglipron
FDA-approved April 2026 as Foundayo for chronic weight management; diabetes indication still under reviewRetatrutide
Investigational, in Phase 3; not approved anywhere- Marketed for
Orforglipron
Weight loss, type-2 diabetesRetatrutide
Weight loss- Outcome areas
Orforglipron
Weight loss / appetite; Blood sugar / insulin sensitivityRetatrutide
Weight loss / appetite- Evidence grade
Orforglipron
FDA-approvedRetatrutide
Clinical data- How it works
Orforglipron
Small-molecule, non-peptide GLP-1 receptor agonist that survives digestionRetatrutide
Activates GIP, GLP-1 and glucagon receptors at once- Route and dosing
Orforglipron
Oral tablet, once daily (Foundayo label); maintenance 5.5 mg or higher once daily, by response and tolerabilityRetatrutide
Once-weekly injection- Headline human result
Orforglipron
11.2% mean weight loss vs 2.1% on placebo at 72 weeks (ATTAIN-1, 36 mg daily)Retatrutide
24.2% mean weight loss vs 2.1% on placebo at 48 weeks (Phase 2 (obesity), 12 mg weekly)- Strongest evidence
Orforglipron
ATTAIN-1, NEJM 2025Orforglipron evidence reviewPubMed 40960239Retatrutide
Phase 2, NEJM 2023Retatrutide evidence reviewPubMed 37366315- Key safety signal
Orforglipron
Dose-related nausea, vomiting and diarrhea; no long-term cardiovascular or renal outcomes trial yetRetatrutide
Common, dose-related nausea, vomiting and diarrhea; long-term safety of the glucagon component unknown- How it is obtained
Orforglipron
Prescription drugRetatrutide
Legitimately available only inside clinical trials; vials sold online are gray-market research chemicals
| Orforglipron | Retatrutide | |
|---|---|---|
| FDA status / approved use | FDA-approved April 2026 as Foundayo for chronic weight management; diabetes indication still under review | Investigational, in Phase 3; not approved anywhere |
| Marketed for | Weight loss, type-2 diabetes | Weight loss |
| Outcome areas | Weight loss / appetite; Blood sugar / insulin sensitivity | Weight loss / appetite |
| Evidence grade | FDA-approved | Clinical data |
| How it works | Small-molecule, non-peptide GLP-1 receptor agonist that survives digestion | Activates GIP, GLP-1 and glucagon receptors at once |
| Route and dosing | Oral tablet, once daily (Foundayo label); maintenance 5.5 mg or higher once daily, by response and tolerability | Once-weekly injection |
| Headline human result | 11.2% mean weight loss vs 2.1% on placebo at 72 weeks (ATTAIN-1, 36 mg daily) | 24.2% mean weight loss vs 2.1% on placebo at 48 weeks (Phase 2 (obesity), 12 mg weekly) |
| Strongest evidence | ATTAIN-1, NEJM 2025Orforglipron evidence reviewPubMed 40960239 | Phase 2, NEJM 2023Retatrutide evidence reviewPubMed 37366315 |
| Key safety signal | Dose-related nausea, vomiting and diarrhea; no long-term cardiovascular or renal outcomes trial yet | Common, dose-related nausea, vomiting and diarrhea; long-term safety of the glucagon component unknown |
| How it is obtained | Prescription drug | Legitimately available only inside clinical trials; vials sold online are gray-market research chemicals |
marks a row where the two differ. “Not established” marks a cell the available evidence does not answer. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
- FDA-approved:
- Approved by the FDA for a defined indication, on the strength of pivotal human trials.
- Clinical data:
- Tested in humans — but investigational, discontinued, or proven only on a surrogate marker (not the marketed outcome).
Our verdict
Orforglipron can now be prescribed: the FDA approved it for weight management in April 2026 as Foundayo. Retatrutide is still investigational and legitimately available only inside a clinical study. Retatrutide has the far larger effect. In its 48-week Phase 2 obesity trial the 12 mg dose produced about 24.2% mean weight loss, and in the Phase 3 TRIUMPH-1 trial Lilly reported 25.0% at 80 weeks versus 3.9% on placebo across everyone randomized (28.3% among people who stayed on treatment), results not yet peer-reviewed. Orforglipron produced about 11% in ATTAIN-1, but it is a once-daily non-peptide tablet with no food or water restrictions, which is the entire point of the molecule. They have not been compared directly, and neither has long-term cardiovascular or renal outcomes data.
Orforglipron fits if
You think the binding constraint on GLP-1 therapy is manufacturing, cost, and adherence rather than peak efficacy.
Retatrutide fits if
You are following the upper limit of what incretin pharmacology can do and accept a drug that is not yet approved, with Phase 3 results still awaiting peer review.
Orforglipron vs Retatrutide: common questions
- Is orforglipron FDA-approved but retatrutide not?
- Yes. Orforglipron was FDA-approved in April 2026 as Foundayo for chronic weight management; diabetes indication still under review. Retatrutide is investigational, in Phase 3; not approved anywhere.
- Which has stronger human evidence, orforglipron or retatrutide?
- Orforglipron. It has approval-level evidence (key source: ATTAIN-1, NEJM 2025), while retatrutide has human clinical data (key source: Phase 2, NEJM 2023).
- What are the main safety concerns with orforglipron and retatrutide?
- For orforglipron, watch for dose-related nausea, vomiting and diarrhea; no long-term cardiovascular or renal outcomes trial yet. For retatrutide, watch for common, dose-related nausea, vomiting and diarrhea; long-term safety of the glucagon component unknown.
Key studies behind each
Orforglipron
- Frias JP, Hsia S, Eyde S, et al. (2023). Efficacy and safety of oral orforglipron in patients with type 2 diabetes: a multicentre, randomised, dose-response, phase 2 study. Lancet. PubMed 37369232
- Wharton S, et al. (2025). Treatment with orforglipron, an oral glucagon-like peptide-1 receptor agonist, is associated with cardiometabolic improvements. Cardiovasc Diabetol. PubMed 40481478
- Rosenstock J, Frias JP, Rodbard HW, et al. (2025). Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist, in Early Type 2 Diabetes. N Engl J Med. PubMed 40544435
- Wharton S, Aronne LJ, Wadden TA, et al. (2025). Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment. N Engl J Med. PubMed 40960239
Retatrutide
- Jastreboff AM, Kaplan LM, Frías JP, et al. (2023). Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med. PubMed 37366315
- Rosenstock J, Frias J, Jastreboff AM, et al. (2023). 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. PubMed 37385280
The full evidence reviews
- Orforglipron: the oral non-peptide GLP-1, and what the trials actually show
A once-daily small-molecule GLP-1 pill with no food restrictions — from Phase 2 proof of concept to the Phase 3 read-outs. The evidence, graded.
Updated August 2026
- Retatrutide: the triple agonist and what its Phase 2 data actually show
A single peptide hitting GIP, GLP-1 and glucagon produced the largest weight-loss numbers yet reported — in Phase 2. A straight read of the evidence and its limits.
Updated August 2026