Orforglipron vs Substance P
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Orforglipron
Orforglipron (LY3502970) is a non-peptide, oral GLP-1 receptor agonist developed by Eli Lilly. Unlike oral semaglutide (which is a peptide requiring special formulation), orforglipron is a small molecule — the first of a new class of oral GLP-1 drugs that can be taken without fasting restrictions. It is in Phase 3 trials for obesity and type 2 diabetes, with an FDA decision expected in 2026. Projected to reach $16 billion in annual sales by 2031.
Full details →Substance P
Substance P is an 11-amino acid neuropeptide involved in pain transmission, inflammation, and various neurological processes. While not used therapeutically itself, understanding it is crucial for pain research.
Full details →Side-by-Side Comparison
| Aspect | Orforglipron | Substance P |
|---|---|---|
| Dose Range | 12 mg–45 mg | 35 mcg–350 mcg |
| Frequency | 1x daily | 1x daily |
| Cycle Length | — | 1 weeks |
| Route | oral | subcutaneous |
| Mechanism | Orforglipron is a small-molecule agonist that binds and activates the GLP-1 receptor through the same signaling cascade as peptide GLP-1 agonists (cAMP elevation, insulin secretion, appetite suppression) but with a fundamentally different molecular structure. Being a non-peptide, it does not require protection from enzymatic degradation (no fatty acid conjugation needed), can be absorbed without special formulation, and has no fasting restrictions for administration. Once-daily oral dosing with a half-life of ~25-65 hours. | Binds primarily to NK1 receptors to transmit pain signals from peripheral nerves to the CNS. Also promotes inflammation, causes vasodilation, and stimulates immune cells. |
| Typical Dosage | Phase 2 trial doses: 12 mg, 24 mg, 36 mg, and 45 mg daily. The 36 mg and 45 mg doses showed greatest efficacy. Phase 3 trials are evaluating doses of 12-60 mg daily. No fasting requirement — can be taken with or without food at any time of day. Final approved dosing not yet established. | Not used as a therapeutic agent. NK1 receptor antagonists (blocking Substance P) are used clinically for chemotherapy-induced nausea. |
| Administration | Oral tablet, once daily. No fasting restrictions required (a major advantage over oral semaglutide). Phase 3 trials ongoing. Expected FDA decision in 2026. Not yet commercially available. | Research compound only. Therapeutic applications focus on blocking rather than administering Substance P. |
| Side Effects | Phase 2 data: nausea (up to 35%), vomiting (up to 19%), diarrhea (up to 18%), constipation, decreased appetite. GI side effects were dose-dependent and generally transient, decreasing with continued use. Discontinuation rates due to GI events were 6-12%. | Administration would cause pain, inflammation, and neurogenic responses. Not given therapeutically. |
| Best For |
Key Differences
Unique to Orforglipron:
Unique to Substance P:
Key Studies
Orforglipron
- Efficacy and safety of once-daily oral orforglipron compared with oral semaglutide in adults with type 2 diabetes (ACHIEVE-3): a multinational, multicentre, non-inferiority, open-label, randomised, phase 3 trial.
Lancet (London, England), 2026
- Orforglipron for maintenance of body weight reduction: the double-blind, randomized phase 3b ATTAIN-MAINTAIN trial.
Nature medicine, 2026
- Orforglipron Added to Titrated Insulin Glargine in Type 2 Diabetes: The ACHIEVE-5 Randomized Clinical Trial.
JAMA, 2026
Substance P
- Revisiting the role of Substance P and CGRPα.
eLife, 2025
- Biochemistry, Substance P.
2023
- Substance P-Friend or Foe.
Journal of clinical medicine, 2022
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