Retatrutide vs VIP (Vasoactive Intestinal Peptide)
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Retatrutide
Retatrutide (LY3437943) is a first-in-class triple agonist peptide targeting GIP, GLP-1, and glucagon receptors simultaneously. Developed by Eli Lilly, it is currently in Phase 3 clinical trials and has demonstrated the highest weight loss of any obesity medication to date — up to 28.7% body weight reduction at 48 weeks. The triple-receptor mechanism represents the next evolution beyond dual agonists like tirzepatide.
Full details →VIP (Vasoactive Intestinal Peptide)
VIP is a 28-amino acid neuropeptide with wide-ranging effects throughout the body. It acts as a neurotransmitter, neuromodulator, and immune regulator with particular importance in gut and lung function.
Full details →Side-by-Side Comparison
| Aspect | Retatrutide | VIP (Vasoactive Intestinal Peptide) |
|---|---|---|
| Mechanism | Retatrutide is a synthetic peptide that activates three incretin/metabolic hormone receptors: (1) GLP-1 receptor — appetite suppression, insulin secretion, delayed gastric emptying, (2) GIP receptor — enhanced insulin sensitivity, improved fat metabolism, (3) Glucagon receptor — increased energy expenditure, hepatic fat mobilization, thermogenesis. The glucagon receptor component is the key differentiator, adding an energy-expenditure mechanism absent from GLP-1 and dual GIP/GLP-1 agonists. The molecule uses a C20 fatty diacid for albumin binding, enabling once-weekly dosing. | Binds to VPAC1 and VPAC2 receptors to modulate immune responses, regulate circadian rhythms, promote vasodilation, and support barrier function in gut and lungs. Has potent anti-inflammatory effects. |
| Typical Dosage | Phase 2 trial doses: 0.5 mg, 4 mg, 8 mg, and 12 mg weekly. The 12 mg dose produced maximum weight loss (28.7%). Phase 3 trials are evaluating doses up to 12 mg. Dose escalation schedule similar to other GLP-1s (start low, increase every 4 weeks). Final approved dosing not yet established — Phase 3 trials ongoing. | Intranasal: 50-200mcg 1-3 times daily for chronic inflammatory conditions. Some protocols use subcutaneous administration. Dosing varies by condition. |
| Administration | Subcutaneous injection, once weekly. Phase 3 trials use pre-filled single-dose pens. Not yet commercially available — estimated FDA approval ~2027-2028. | Intranasal is most common for inflammatory conditions. Subcutaneous injection also used. Must be stored cold and protected from light. |
| Side Effects | Phase 2 data: nausea (up to 25%), diarrhea (up to 22%), vomiting (up to 15%), constipation, decreased appetite. GI side effects were dose-dependent and generally mild-to-moderate. Lower rates of nausea compared to semaglutide, potentially due to GIP component. Increased heart rate observed at higher doses. | May cause nasal irritation, flushing, headache, or temporary diarrhea. Generally well-tolerated at standard doses. |
| Best For |
Key Differences
Unique to Retatrutide:
Unique to VIP (Vasoactive Intestinal Peptide):
Detailed Analysis
Commonalities
Retatrutide and VIP (Vasoactive Intestinal Peptide) are used for different purposes and have limited overlap in their applications.
Which Should You Choose?
Choose Retatrutide for Fat Loss. Choose VIP (Vasoactive Intestinal Peptide) for Sleep Quality, Immune Support, Gut Health.
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