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Select any two compounds for a side-by-side comparison of mechanism, uses, risks, and FDA regulatory status.
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LL-37
Cathelicidin, Human Cathelicidin Antimicrobial Peptide
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.
The only human cathelicidin antimicrobial peptide, LL-37 is a 37-amino-acid peptide naturally produced by immune cells, epithelial cells, and barrier tissues. It plays a critical role in innate immunity by directly killing bacteria, viruses, and fungi, while also modulating inflammatory responses. Increasingly studied for chronic infections, biofilm disruption, and immune regulation.
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.
Disrupts microbial membranes through electrostatic interaction with negatively charged bacterial surfaces, creating pores that kill pathogens. Also modulates immune responses by recruiting immune cells, promoting wound healing, and disrupting bacterial biofilms. Acts as a bridge between innate and adaptive immunity.
- Chronic inflammatory response syndrome (CIRS)
- Mold illness treatment (Shoemaker protocol)
- Pulmonary hypertension
- Neuroinflammation
- GI motility disorders
- Immune system support
- Chronic infection management
- Biofilm disruption (Lyme, SIBO)
- Wound healing
- Upper respiratory infection support
- Hypotension (due to vasodilation)
- Diarrhea at higher doses
- Nasal irritation with intranasal use
- Flushing and headache
- Limited standardized clinical data for CIRS indication
- Injection site reactions (pain, redness)
- Potential autoimmune activation at high doses
- Limited human clinical data for therapeutic use
- Overexpression linked to psoriasis and rosacea in some contexts
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.
Not FDA-approved as a therapeutic. LL-37 is an endogenous human peptide being studied in clinical trials for wound healing and infection. Some compounding pharmacies have offered it, but it has no formal FDA category for compounding. Research is ongoing for topical wound applications.
This comparison is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide therapy.