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Immune
The human body's own antimicrobial peptide, cut from cathelicidin.
Immune
A 28-amino-acid neuropeptide that relaxes blood vessels and calms inflammation.
LL-37 is not FDA-approved and rated 3/5 for evidence; VIP is not FDA-approved and rated 3/5. They have a similar amount of human evidence. LL-37 is banned in sport by WADA; VIP is not. Both are used for immune goals.
| Compare | LL-37 The human body's own antimicrobial peptide, cut from cathelicidin. | VIP A 28-amino-acid neuropeptide that relaxes blood vessels and calms inflammation. |
|---|---|---|
| Category | Immune | Immune |
| Evidence | 3/5Small human trials of topical LL-37 for venous leg ulcers; a larger Phase IIb missed its overall goal. No human data for injection. | 3/5Real human data (ED approval in the UK, small lung studies, a large COVID RCT that failed). CIRS nasal use is small open-label work only. |
| FDA status | Not FDA-approved | Not FDA-approved |
| WADA (sport) | Banned | Not on the Prohibited List |
| Also known as | Cathelicidin, hCAP-18 fragment, Ropocamptide | Vasoactive intestinal peptide, Aviptadil, Zyesami |
| How it works | A positively charged peptide that disrupts microbe membranes and breaks up biofilms. It also signals immune cells and supports wound closure. The same immune-activating effect is linked to psoriasis, rosacea and lupus when it is overactive. | Binds VPAC1 and VPAC2 receptors. That relaxes smooth muscle in vessels and airways, reduces inflammatory cytokines and shifts immune cells toward a calmer profile. It breaks down within minutes in the blood. |
| Half-life | Not established in humans; broken down quickly by proteases | About 2 minutes in blood |
| Commonly reported doses |
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| Route | Subcutaneous | Intranasal (spray) |
| Good once mixed | ~28 days in the fridge | ~14 days in the fridge |
| Top side effects |
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| Lowest research-listing price per mg | $4.20 (5 mg vial, 40% off) | $3.00 (10 mg vial, 40% off) |
| Latest lab purity | 99.68% (lot LL0002) | 99.90% (lot VIP0002) |
Want a third? Add another peptide. Doses are commonly reported ranges, not recommendations.
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LL-37 is not FDA-approved and rated 3/5 for evidence; VIP is not FDA-approved and rated 3/5. They have a similar amount of human evidence. LL-37 is banned in sport by WADA; VIP is not. Both are used for immune goals.
LL-37: Not FDA-approved. VIP: Not FDA-approved. Regulations change, so confirm with the FDA.
LL-37 is rated 3 out of 5: Small human trials of topical LL-37 for venous leg ulcers; a larger Phase IIb missed its overall goal. No human data for injection. VIP is rated 3 out of 5: Real human data (ED approval in the UK, small lung studies, a large COVID RCT that failed). CIRS nasal use is small open-label work only. The scale is explained on our methodology page.
LL-37 is banned by WADA, by name or as part of a named class. VIP is not named on the WADA list, though the general rule on non-approved substances (S0) can still apply.