Thymosin Alpha-1 vs LL-37
Thymosin alpha-1 has condition-specific human immunomodulatory trials and non-US approvals; LL-37 has mixed native topical wound-trial outcomes. Their different indications do not support a general immune-benefit ranking.
Last updated: September 28, 2026
Dossier labels summarize each dossier's research scope. They do not establish comparative treatment benefit or safety. Read the comparison below in that context.
Thymosin Alpha-1
Dossier overview
LL-37
Dossier overview
Different indications and mechanisms
Thymosin alpha-1 (thymalfasin) is a 28-residue immunomodulatory peptide with human trials in defined diseases, including chronic hepatitis B. LL-37 is the mature 37-residue human cathelicidin peptide with experimental antimicrobial and context-dependent inflammatory signaling. These mechanisms do not establish a preferred general immune treatment. thymosin-alpha-1 hepatitis trial, PMID 9581695 · LL-37 processing, PMID 8681941 · LL-37 rosacea mechanism, PMID 17676051
| Evidence question | Thymosin alpha-1 | LL-37 |
|---|---|---|
| Direct human treatment | Controlled trials in specific illnesses; results vary | Three native topical wound-trial populations; mixed results |
| Regulatory boundary | Approved in some countries according to the C25 dossier; no US FDA-approved product verified here | No FDA-approved LL-37 medicine verified |
| Therapeutic-claim grade | Moderate within studied indications; not a general immune claim | Low for broad wound or anti-infective claims |
In a 98-person chronic hepatitis B trial, a prespecified treatment group had a greater later virological response than untreated controls. A separate 97-person double-blind, placebo-controlled phase III trial did not confirm statistically significant efficacy on its complete-response endpoint. These are indication-specific findings, not proof of broad immunity or infection prevention. PMID 9581695 · PMID 10607256
Native topical LL-37 had selected healing signals in a 34-person venous-ulcer pilot and a diabetic-foot-ulcer cream trial. A larger 148-person venous-ulcer trial found no significant full-population healing benefit, and the diabetic-foot-ulcer study did not significantly reduce measured aerobic bacterial colonization. LL-37 topical pilot, PMID 25041740 · larger phase IIb trial, PMID 34687253 · diabetic-foot-ulcer trial, PMID 37480520
A completed melanoma registry posts intratumoral LL-37 outcomes for just four people; it is not a topical trial or general cancer result. Engineered L. lactis expressing LL-37 is a different oral intervention, with nonsignificant overall viral-negative-time results. NCT02225366 · PMID 37605995
The C25 thymosin alpha-1 dossier reports non-US approvals, but the exact country/indication list has not been independently reverified in this comparison packet; no precise country count is used here. FDA describes insufficient safety information for compounded LL-37. Neither source stream establishes safety or benefit from combining the two peptides. FDA compounding safety review
This selected-source review is educational, not advice to use either peptide.
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Disclaimer: This comparison is for educational purposes only and does not constitute medical advice. Individual responses to medications vary. Always consult a qualified healthcare provider before making treatment decisions.