Peptides marketed for immune support

These are compounds sold for immune support — this is not a recommendation list, and nothing here is ranked. Of the 4 we track with this claim, 2 have any registered human trial at all, 1 has one that actually studied immune support, and 0 are FDA-approved for any indication.

"Immune support" is an unusually vague claim: an immune system can be over-active or under-active, and the same compound cannot sensibly be good for both. The registered trials here study specific diseases — hepatitis, sepsis, cancer — rather than immunity in a healthy person.

Thymosin α1

Thymalfasin · Zadaxin · Tα1

Genuinely well-studied, but the trials are in hepatitis, cancer and sepsis. None lists an autoimmune condition as its primary indication.

Studied for immune support

Registered trials

LL-37

Cathelicidin · hCAP18 fragment

The body’s only cathelicidin antimicrobial peptide. Two registered trials — and published human trials that were never registered.

Trials, but not for immune support

Registered trials

KPV

Lysine-Proline-Valine · alpha-MSH 11-13

An alpha-MSH fragment marketed for inflammation and gut health. Zero registered human trials.

No registered trial

Registered trials

Thymalin

Thymus peptide extract

A calf-thymus extract sold as an immune and longevity peptide. Zero registered human trials in the registries we track.

No registered trial

Registered trials

—Read this

Marketed for is not tested for

A compound can be sold for immune support and studied for something else entirely — that is the most common pattern on this site, not the exception. A row saying "trials, but not for immune support" means registered studies exist and none of them asked this question. It is not a claim that the compound does nothing.

See all 42 compounds →