Head to head
Thymosin Alpha-1 against LL-37
Two immune peptides pulling in different directions, a thymic modulator approved in many countries for hepatitis and the body's own antimicrobial cathelicidin whose role in disease is documented as double-edged.
Column A
Thymosin Alpha-1Thymosin Alpha-1 (Thymalfasin)
An immune-modulating thymic peptide approved in many countries for hepatitis and used as an immune adjuvant.
Column B
LL-37LL-37 (human cathelicidin antimicrobial peptide)
The main human cathelicidin antimicrobial peptide, central to innate immunity and wound healing, with a complex double-edged role in disease.
Side by side, on the facts we can check
| Attribute | Thymosin Alpha-1 | LL-37 |
|---|---|---|
| Category | Immune | Immune |
| FDA status | Not FDA-approved (orphan status); approved in 30+ countries as Zadaxin | Not FDA-approved; research peptide |
| Half-life | ~2 hours | Short |
| Molecular weight | 3,108 Da | 4,493.3 Da |
| Mechanism | Enhances T-cell maturation and function, modulates dendritic cells and cytokine signaling, and supports both adaptive and innate immune responses. | Disrupts microbial membranes and modulates immune cell activity, wound repair, and inflammation. |
| Human studies cited | 2 | 2 |
| Legal status, US | Not fully approved; orphan-drug designation only | Not approved; research use only |
Frequently asked questions
What is the difference between Thymosin Alpha-1 and LL-37?
Thymosin Alpha-1: An immune-modulating thymic peptide approved in many countries for hepatitis and used as an immune adjuvant. LL-37: The main human cathelicidin antimicrobial peptide, central to innate immunity and wound healing, with a complex double-edged role in disease.
Which has stronger research evidence, Thymosin Alpha-1 or LL-37?
This database does not grade compounds. It counts what was run in people: 2 of the 4 studies cited on the Thymosin Alpha-1 profile were human work, against 2 of 4 for LL-37. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Thymosin Alpha-1 and LL-37 FDA-approved?
Thymosin Alpha-1: Not FDA-approved (orphan status); approved in 30+ countries as Zadaxin. LL-37: Not FDA-approved; research peptide.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.