What Are GLP-1 Peptides?
GLP-1 (glucagon-like peptide-1) receptor agonists are a class of peptides that mimic incretin hormones to regulate blood sugar, slow gastric emptying, and reduce appetite. Originally developed for type 2 diabetes, they became a cultural phenomenon after demonstrating significant weight loss in clinical trials. Three compounds dominate this space — each targeting a different number of receptors.
GLP-1 medications have reshaped the treatment landscape for obesity and type 2 diabetes. Understanding the clinical differences between semaglutide, tirzepatide, and retatrutide is essential for patients exploring their options.
The Three GLP-1 Peptides at a Glance
| Property | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Developer | Novo Nordisk | Eli Lilly | Eli Lilly |
| Brand Names | Ozempic, Wegovy, Rybelsus | Mounjaro, Zepbound | N/A (investigational) |
| Mechanism | GLP-1 only (single) | GLP-1 + GIP (dual) | GLP-1 + GIP + Glucagon (triple) |
| Molecular Weight | ~4,114 Da | ~4,810 Da | ~4,605 Da |
| FDA Approved | Yes | Yes | No |
| Max Weight Loss (trials) | ~15-17% | ~20-22.5% | ~26-29% (Phase 3) |
Semaglutide — The Market Leader
Semaglutide is the most commercially successful peptide in history. It's the only GLP-1 available in three FDA-approved forms: Ozempic (T2D, injectable), Wegovy (weight management, injectable), and Rybelsus (T2D, oral tablet).
Brand Pricing & Savings
| Product | Indication | List Price | With Savings Programs |
|---|---|---|---|
| Ozempic | Type 2 diabetes | $800-1,200/month | Insurance often covers |
| Wegovy | Weight management | $1,300-1,600/month | As low as $149/month (eligible patients, through Aug 2026) |
| Rybelsus | Type 2 diabetes (oral) | $800-1,000/month | Insurance may cover |
Coming soon: Novo Nordisk announced list price cuts of ~35-50% effective January 1, 2027, bringing all three to approximately $675/month.
Semaglutide Access — What Changed
The FDA removed semaglutide from the drug shortage list on February 21, 2025. This has significantly changed the landscape for patients seeking affordable access:
- Brand-name products (Ozempic, Wegovy, Rybelsus) remain the primary FDA-approved options
- Manufacturer savings programs can significantly reduce out-of-pocket costs for eligible patients
- Insurance coverage continues to expand, particularly for type 2 diabetes indications
Valitide connects patients to direct-pay semaglutide via NovoCare Pharmacy at Novo Nordisk's published self-pay rate — no insurance billing required.
Tirzepatide — The Dual Agonist
Tirzepatide targets two receptors (GLP-1 + GIP), which is why clinical trials showed greater weight loss than semaglutide. Approved as Mounjaro (T2D, May 2022) and Zepbound (weight management, November 2023). Zepbound also received a second approval in December 2024 for moderate-to-severe obstructive sleep apnea in adults with obesity.
Access Options
The FDA declared the tirzepatide shortage resolved (initially October 2024, re-confirmed December 2024). The primary options for tirzepatide are brand Mounjaro or Zepbound. While retail pricing exceeds $1,000/month, Eli Lilly's direct-pay pharmacy LillyDirect ships Zepbound at $299–$499/month — Valitide routes prescriptions there for patients who prefer to skip insurance entirely.
Retatrutide — The Triple Agonist (Investigational)
Retatrutide is the newest and most potent of the three, targeting GLP-1, GIP, and glucagon receptors simultaneously. The glucagon component actively increases energy expenditure and promotes fat oxidation — adding a calorie-burning element the others lack.
Trial Results
- Phase 2 (NEJM): 24.2% weight loss at 48 weeks
- Phase 3 TRIUMPH-4 (Dec 2025): 26.4% at 9mg, 28.7% at 12mg over 68 weeks
- Dose-dependent response confirmed across both phases
Availability
Retatrutide is currently in Phase 3 clinical trials and is not yet FDA-approved. No legitimate pharmaceutical-grade product exists on the market. An NDA filing from Eli Lilly is anticipated but unconfirmed as of early 2026.
Valitide will update this guide when FDA-approved options for retatrutide become available. In the meantime, patients interested in triple-agonist therapy should discuss the clinical trial landscape with their provider.
How Valitide Helps
Valitide connects you with licensed providers who prescribe FDA-approved GLP-1 medications and routes your prescription directly to LillyDirect (for Zepbound) or NovoCare Pharmacy (for Wegovy) at the manufacturer's self-pay rate. No insurance billing, no prior-authorization waits.
- Ongoing care — your provider manages dosing, monitors progress, and adjusts treatment as needed
Join the waitlist — we'll notify you as soon as we begin accepting patients.