Use case

Immune support

Which peptides have meaningful human evidence for immune-support claims?

Context

Immune claims belong next to vaccination, treatment of underlying conditions, and approved immunomodulators; broad immune-boosting language is a marketing frame, not a clinical endpoint.

Compare thymosin alpha-1, thymalin, thymogen, LL-37, and VIP: one approved outside the US with a defined schedule, the rest resting on legacy literature, niche trials, or clinic tradition.

Peptides compared

Limited human evidence

Thymosin alpha-1

An immunomodulatory thymalfasin peptide with older chronic-hepatitis-B evidence, non-U.S. Zadaxin labeling, mixed sepsis and COVID literature, and broad clinic or gray-market immune-support marketing.

Varies by product and jurisdiction

Limited human evidence

Thymalin

Thymalin is a thymus-extract peptide mixture with Soviet-era drug registration and gerontology literature behind it. Modern controlled evidence is lacking, and products outside that lineage are unverified.

Varies by product and jurisdiction

Limited human evidence

Thymogen

Thymogen is a short thymic peptide registered as a nasal immune drug in Russia. Its evidence base is domestic and old; outside that context it is unstudied.

Varies by product and jurisdiction

Limited human evidence

LL-37

LL-37 has host-defense biology, narrow human chronic-wound evidence, and prominent FDA compounding-risk concerns.

Investigational / not approved

Limited human evidence

VIP

VIP (vasoactive intestinal peptide) is an endogenous peptide with human trial history as aviptadil in lung and inflammatory indications. Its clinic use in mold-illness (CIRS) protocols is a separate, unproven practice with real hypotension risk.

Not FDA-approved for listed uses

Sources

1.
ClinicalTrials.gov. ClinicalTrials.gov record NCT02225366 2026.
NCT02225366 Accessed 2026-06-09.
Completed phase 1/2 melanoma registry. The registry shows 4 actual participants, while posted participant-flow, baseline, outcome, and adverse-event denominators report 3 analyzed participants across two cohorts.
2.
PubMed. Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial 2014.
doi:10.1111/wrr.12211 PMID:25041740 Accessed 2026-06-09.
PubMed abstract describes a 34-participant venous leg ulcer trial with placebo run-in, randomized double-blind LL-37 exposure, healing signals in lower-exposure groups, and no local or systemic safety concerns reported in that study.
3.
FDA. Tailor Made Compounding LLC - 594743 - 04/01/2020 2020.
Accessed 2026-06-09.
FDA warning letter lists LL-37 among compounded bulk substances the agency said did not meet the cited section 503A conditions in the circumstances described.
4.
FDA. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee 2026.
Accessed 2026-07-24.
FDA meeting page for the July 23-24, 2026 PCAC review of BPC-157, KPV, TB-500, MOTs-C, emideltide/DSIP, Semax, and Epitalon bulk substances, including the uses evaluated for each, briefing documents, and docket FDA-2025-N-6895.
5.
FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks 2026.
Accessed 2026-06-08.
FDA summarizes potential significant safety risks and missing safety information for several nominated peptide bulk substances.