Compare Peptides
Select any two compounds for a side-by-side comparison of mechanism, uses, risks, and FDA regulatory status.
Popular comparisons
A 28-amino-acid neuropeptide naturally produced throughout the body, with particularly high concentrations in the gut, lungs, and nervous system. VIP has potent anti-inflammatory, vasodilatory, and immunomodulatory properties. It gained significant attention during COVID-19 as aviptadil (synthetic VIP) was studied for acute respiratory distress. In integrative medicine, it is widely used for chronic inflammatory response syndrome (CIRS) and mold illness protocols.
A thymic peptide that plays a central role in immune system regulation. Approved as a drug in over 35 countries (though not in the US) for hepatitis B and C treatment and as an immune booster.
Binds to VPAC1 and VPAC2 receptors, activating cAMP-dependent pathways that suppress pro-inflammatory cytokines (TNF-α, IL-6, IL-12) while promoting anti-inflammatory cytokines (IL-10). Also acts as a potent vasodilator, bronchodilator, and neuroprotective agent. In the lungs, VIP protects alveolar type II cells from inflammatory damage.
Enhances T-cell function, promotes dendritic cell maturation, and modulates cytokine production. Acts as an immune system regulator rather than a simple stimulant, helping to balance immune responses.
- Chronic inflammatory response syndrome (CIRS)
- Mold illness treatment (Shoemaker protocol)
- Pulmonary hypertension
- Neuroinflammation
- GI motility disorders
- Immune system support
- Chronic infection management
- Cancer adjunct therapy (in some countries)
- Post-illness recovery
- Autoimmune condition management
- Hypotension (due to vasodilation)
- Diarrhea at higher doses
- Nasal irritation with intranasal use
- Flushing and headache
- Limited standardized clinical data for CIRS indication
- Generally well-tolerated in clinical use
- Injection site reactions
- Rare allergic reactions
- May interact with immunosuppressive drugs
Aviptadil (synthetic VIP) has been studied in clinical trials for ARDS and pulmonary hypertension. Not FDA-approved for any indication. Used off-label by integrative medicine practitioners for CIRS. The Shoemaker CIRS protocol includes intranasal VIP as a final step, though this use is not FDA-sanctioned.
Reclassified to Category 1 in February 2026 as part of the HHS announcement restoring compounding access. Not affected by the April 15, 2026 Category 2 removal action. Approved as Zadaxin in 35+ countries but not FDA-approved in the US. Available through licensed 503A compounding pharmacies with a physician prescription.
This comparison is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide therapy.