Immune Stack
AKA Thymosin alpha-1 + LL-37
Last reviewed 2026-10-30
Our read Opinion
Functional-medicine immune protocol.
Claims made by sellers, clinics and users. Not verified.
Stronger immune defense, faster recovery from infections, and support for chronic infections or mold illness.
Thymosin alpha-1 tunes adaptive (T-cell) immunity; LL-37 is an innate antimicrobial peptide, so together they're pitched as covering both arms of the immune system.
Evidence level: Small/early human studies
Thymosin alpha-1 has human trial data and foreign approvals; LL-37 has small studies. No published human trials of this combination.
Thymosin alpha-1 remains on Category 2 (verify); LL-37 is off Category 2 but not cleared for compounding.
Statuses change; check the linked primary sources.
Thymosin alpha-1 is one of the better-supported research peptides; adding LL-37 is guesswork.
| Field | Thymosin Alpha-1 | LL-37 |
|---|---|---|
| Type | Approved Outside US | Investigational |
| Regulatory status | Approved outside US; not FDA-approved | Not FDA-approved; no verified marketing authorization |
| Compounding status | Not cleared (advisory panel rejected) | Off Category 2, review pending |
| FDA-approved indications | None | None |
| Categories | Immune | Immune |
| Claimed uses |
|
|
| Mechanism | Synthetic counterpart of an endogenous thymic peptide that modulates dendritic-cell and T-cell responses. Toll-like-receptor signaling is implicated in its immunomodulatory effects. | Human cathelicidin antimicrobial peptide with membrane-disrupting and immune-signaling activities. Its effects on inflammation and tissue repair are context dependent. |
| Evidence level | Human RCTs (approved use) | Small/early human studies |
| Evidence / Hype (opinion) | Evidence Hype | Evidence Hype |
| Momentum (opinion) | Watch | Watch |
| Routes | — | — |
| WADA | Verify | Verify |
| Where it stands (opinion) | Human trials exist, but evidence varies substantially by disease. The December 2024 FDA advisory committee voted against adding thymosin alpha-1 forms to the 503A bulks list. | Published ulcer trials provide human evidence, but active trial status is unverified. FDA moved the nomination to its withdrawn table and still flags safety uncertainties, including nonclinical tumor-related concerns. |
| Last reviewed | 2026-10-30 | 2026-10-30 |
| News (30d) | 0 | 0 |
No news yet for these peptides.
Information only. Not medical advice. Describing a stack is not a recommendation to combine, obtain or use any compound. Ratings and "Our Take" are editorial opinion. Full disclaimer.