Mechanism Comparison
| Property | Orforglipron | Retatrutide |
|---|---|---|
| Class | Non-peptide GLP-1 agonist | Triple GLP-1+GIP+GCGR agonist |
| Administration | Oral (tablet) | Subcutaneous injection |
| Half-life | ~5 days | ~6 days |
| Frequency | Once daily (oral) | Once weekly (injection) |
| GLP-1R activity | Yes | Yes |
| GIPR activity | No | Yes |
| GCGR activity | No | Yes |
Efficacy Data
Phase 2/3 data for Orforglipron (Eli Lilly) showed approximately 14.7% weight reduction at 36 weeks in the highest dose arm (45 mg daily). Retatrutide's Phase 2 data showed up to 22.8% weight reduction at 48 weeks in the 12 mg weekly arm — making Retatrutide the more potent compound by body weight reduction metrics to date.
However, Orforglipron's key advantage is oral bioavailability. Unlike injectable GLP-1 peptides (including semaglutide and tirzepatide), Orforglipron does not require cold chain storage or injection equipment, which dramatically changes the research logistics profile.
Side Effect Profiles
Both compounds share the expected GLP-1 class GI side effects (nausea, vomiting, diarrhoea). Orforglipron's GI adverse event rates were slightly lower than those of Retatrutide at equivalent efficacy tiers — largely because GIP and glucagon receptor co-activation by Retatrutide amplifies early GI symptoms during titration.
Orforglipron showed no significant injection site reactions (as expected for an oral compound). Retatrutide injection site reactions were mild and self-limiting in approximately 7–10% of Phase 2 participants.
Research Context: Which to Choose?
For researchers studying the comparative pharmacology of GLP-1 class compounds, Retatrutide is the more powerful tool for understanding triple-receptor agonism — a mechanism unique among currently researched compounds. Its glucagon receptor activity creates distinct metabolic effects (enhanced fat oxidation, greater energy expenditure) not achievable with GLP-1 mono or dual agonists.
Orforglipron is of interest primarily for research into oral peptide bioavailability — how a non-peptide small molecule can activate the same receptor as a large peptide like semaglutide. Both compounds are available from QSC for research purposes.
Availability from QSC
QSC supplies both Retatrutide (injectable, 10 mg vials) and Orforglipron (oral tablets, 10 mg) for research use. Both ship from domestic US, EU, UK, AU, CA, and Asia warehouses with ≥99% HPLC purity and Janoshik COA documentation on every batch.
Source Research-Grade Retatrutide
QSC Retatrutide (RT10) — 10 mg vials, ≥99% HPLC purity, Janoshik COA on every batch. Domestic US, EU, UK, AU, CA, and Asia warehouses.
View Retatrutide at QSC →