KPV vs LL-37: evidence, immune effects, legal status

Which is better, KPV or LL-37?

LL-37 has the higher evidence grade (human RCT) because a 34 patient phase I/II trial found faster venous ulcer healing with the two lower gel doses, but a larger phase IIb trial did not confirm it overall, and no data exist for injected LL-37. KPV is animal only; it was recommended for the 503A bulks list in July 2026 but awaits an FDA final rule, so neither has a lawful compounded path today. For a chronic wound, LL-37 gel is the one with human data; for gut inflammation or systemic use, neither has human evidence. [1] [2] [3] [4] [5]

How do KPV and LL-37 compare?

KPV and LL-37 compared by dimension
Dimension	KPV	LL-37
What it is [3] [6]	Synthetic tripeptide (lysine-proline-valine), the C-terminal fragment of alpha-MSH.	Human cathelicidin antimicrobial peptide (37 amino acids) cleaved from the hCAP18 precursor.
Mechanism [3] [6]	Taken into gut and immune cells by PepT1, then inhibits NF-kB and MAP kinase inflammatory signaling.	Disrupts bacterial membranes, neutralizes lipopolysaccharide, recruits immune cells through FPR2, and stimulates keratinocyte migration and angiogenesis.
Direction of immune effect [6] [7]	Anti-inflammatory: dampens cytokine release.	Mixed: antimicrobial and pro healing at low concentrations, but pro inflammatory and cytotoxic at high concentrations and elevated in psoriasis and rosacea lesions.
Human evidence [1] [2] [3]	No indexed human trial for any indication.	Two randomized trials of topical gel in venous leg ulcers: faster healing at the two lower concentrations in 34 patients; the phase IIb trial missed its primary endpoint overall.
Main animal evidence [3] [6] [7]	Reduced DSS and TNBS colitis in mice, confirmed by a second lab in DSS and T cell transfer colitis.	Accelerated wound healing and protected against bacterial infection in rodent skin, lung, and sepsis models.
Theoretical safety concern [3] [6]	Immune dampening could impair response to infection (not shown).	May worsen psoriasis, rosacea, or lupus, where it is thought to drive inflammation; cytotoxic at high concentrations.
FDA and compounding status [4] [5]	Removed from 503A Category 2 on April 15, 2026 and recommended for the 503A bulks list by PCAC in July 2026; no final rule yet.	Withdrawn from 503A Category 2 after its nomination was withdrawn, and not among the peptides PCAC recommended in July 2026, so it sits in neither category and has no lawful compounded path.
WADA status [8]	Prohibited at all times under S0 (non-approved substances).	Prohibited at all times under S0 (non-approved substances).
Typical cost and access [4] [5]	No lawful compounded price: not on the 503A bulks list, and advertised clinic prices are not a comparable price.	No lawful compounded price: off Category 2 but not on the 503A bulks list and not recommended by PCAC. Research chemical vials are not lawful for human use.

Evidence grade and regulatory status

Pulled from each peptide’s own record, so it stays in step with the peptide pages.

KPV and LL-37: grade, status, and cost
Attribute	KPV	LL-37
Class	Synthetic tripeptide (lysine-proline-valine), the C-terminal fragment of alpha-melanocyte stimulating hormone (alpha-MSH)	Human cathelicidin antimicrobial peptide (37 amino acids, cleaved from the hCAP18 precursor)
What it is	Anti-inflammatory fragment of the hormone alpha-MSH; mouse colitis data, no human trial; recommended for FDA's compounding list in July 2026, rule pending.	The only human cathelicidin, a germ-killing peptide. A skin gel had two small leg ulcer RCTs; no human data for injections. Off FDA Category 2 since April 2026.
Evidence	Evidence: Animal-only evidence	Evidence: Human RCT evidence
FDA status	Regulatory: Under FDA review	Regulatory: Removed from Category 2 (Apr 2026)
Compounding	Removed from the FDA 503A Category 2 list on April 15, 2026. On July 23 to 24, 2026 the Pharmacy Compounding Advisory Committee recommended adding KPV to the 503A bulks list. As of the last verification date FDA has not published a final rule listing it, so it is not on the 503A bulks list and a 503A pharmacy has no federal basis to compound it from bulk; state boards cannot authorize what federal law does not. It is not an FDA approved drug and is not eligible for 503B outsourcing. Products sold as research chemicals or as dietary supplements are not lawful for human drug use.	Not an FDA approved drug. LL-37 was placed on the FDA 503A Category 2 list (bulk substances with significant safety risks) in 2023 and was one of the peptides FDA now lists as withdrawn from 503A Category 2 (page current as of April 22, 2026) after the nominations were withdrawn. It was not among the peptides the Pharmacy Compounding Advisory Committee recommended for the 503A bulks list at its July 23 to 24, 2026 meeting, so it currently sits in neither category and most 503A pharmacies will not compound it. Not eligible for 503B outsourcing.
WADA	WADA: WADA prohibited	WADA: WADA prohibited
Routes	Oral capsule (as sold), Subcutaneous injection (as sold), Topical cream and nasal spray (as sold), Oral in drinking water and intraperitoneal (mouse studies)	Topical gel on chronic wounds (clinical trials), Subcutaneous injection (as sold, no human data), Nebulized or intranasal (as sold, no human data)
Typical cost	No lawful compounded price: KPV is not on the 503A bulks list, and PCAC's July 2026 recommendation is advisory until FDA publishes a final rule. Advertised clinic prices are not a comparable price. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity.	Products sold as research chemicals are not lawful for human use and are not verified for identity or purity. Not routinely available through licensed telehealth or compounding channels as of the last verified date.
Last verified	Sep 23, 2026	Sep 22, 2026

Has KPV been tested directly against LL-37?

No published trial has compared KPV and LL-37 directly. The dimensions above come from separate studies and labels, and cross-trial comparisons are less reliable than a direct trial.

What do KPV and LL-37 cost?

Typical cost of KPV and LL-37
Dimension	KPV	LL-37
Typical cost	No lawful compounded price: KPV is not on the 503A bulks list, and PCAC's July 2026 recommendation is advisory until FDA publishes a final rule. Advertised clinic prices are not a comparable price. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity.	Products sold as research chemicals are not lawful for human use and are not verified for identity or purity. Not routinely available through licensed telehealth or compounding channels as of the last verified date.
Price detail	KPV price by channel	Price index in progress

Where a price index exists, the range is the cash price per month across branded, compounded, and telehealth channels, without insurance. The cost pages give each channel separately with its sources. Otherwise the typical cost from the peptide record is shown. Legal access depends on your state: see peptide legality by state.

Frequently asked questions

Which has better evidence, KPV or LL-37?

LL-37, but only for a topical gel on venous leg ulcers: a 34 patient trial showed faster healing at the two lower doses, while a larger phase IIb trial missed its primary endpoint. KPV has only mouse data. Neither has human data for injection. [1] [2] [3]

Which is better for gut inflammation?

Neither has been tested in people with gut inflammation. KPV has two independent mouse colitis studies; LL-37 was studied for skin wounds and infection, not bowel disease. [3] [6] [7]

Can LL-37 make inflammatory skin disease worse?

Possibly. LL-37 is elevated in psoriasis and rosacea lesions, where it can complex with self DNA and RNA to activate immune cells, so it is thought to drive inflammation in those conditions. KPV works in the opposite direction by dampening inflammatory signaling. [3] [6]

Can a pharmacy compound KPV or LL-37?

Not from bulk today. KPV was removed from Category 2 and recommended for the 503A bulks list in July 2026, but the recommendation is advisory: until FDA publishes a final rule, a 503A pharmacy has no federal basis to compound it from bulk. LL-37 is off Category 2 but was not recommended, so it sits in neither category and has no lawful compounded path. [4] [5]

Are KPV and LL-37 allowed in sport?

No. Both are prohibited at all times under S0 of the WADA Prohibited List as non-approved substances. [8]

Conditions studied

Sources

Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.

Cite this page

Free to cite and quote with a link. Data is licensed CC BY 4.0 with attribution to PeptideAgent.

APA style: PeptideAgent. (2026, September 23). KPV vs LL-37: evidence, cost, and legality. https://peptideagent.ai/compare/kpv-vs-ll-37
HTML link: <a href="https://peptideagent.ai/compare/kpv-vs-ll-37">KPV vs LL-37: evidence, cost, and legality</a>, PeptideAgent, updated September 23, 2026.