Thymosin alpha-1
Sleep & Recovery · Immunomodulatory peptide
Tier C+
Bottom line
Read Off Label grades Thymosin alpha-1 as C+ (5.7/10) based on weak evidence, med benefit magnitude, and a low-risk safety profile.
Approved in >30 countries (not US).
Studied, labeled, or reported-use context: 1. — Rx in EU, Asia, Russia (Zadaxin); NOT FDA-approved in US; Category 2 on 503A bulks — compounding prohibited as of Jan 2025; not individualized guidance.
Frontier potential — editorial judgment, not evidence
This is a separate axis from the grade above. It asks a different question: if this worked in humans, how much would it matter? It is our judgment, it is not part of the composite score, and it cannot raise a grade. A high number here is a statement about the idea, not about whether it works or whether anyone should take it.
What the ceiling rests on
The most clinically validated peptide in this group — approved in over 30 countries as Zadaxin for hepatitis B and C and as an immune adjuvant, with randomised data in sepsis and a large body of use in immunocompromised patients.
Why it may not get there
The approvals and trials are in specific immune-compromised or infected populations, where restoring T-cell function has a clear rationale. That does not extend to immune enhancement in healthy adults, where no controlled data exist and the direction of benefit is not obvious — modulating an already-functioning immune system is as likely to be neutral or harmful.
What would change this A controlled trial in a healthy or merely ageing (not immunocompromised) population.
What the evidence says
Approved in >30 countries (not US). Wu 2013 meta-analysis in sepsis showed mortality benefit. Used in long-COVID, Lyme, and chronic fatigue protocols with weak evidence. Same Jan 2025 FDA compounding restriction. Generally considered one of the better-studied 'biohacker peptides.'
Mechanism
28-amino-acid peptide derived from thymus prothymosin alpha; stimulates TLR9/Th1 immunity; activates dendritic cells and T-cell maturation; used in Europe/Asia for hepatitis B/C, sepsis, as vaccine adjuvant
Studied, labeled, or reported dose & route
1.6 mg subQ 2x/week (hepatitis indications); biohacker dosing similar
This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.
Citations
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Common questions
- What does the evidence show about Thymosin alpha-1's effects?
- Read Off Label rates the evidence for Thymosin alpha-1 as Weak and the benefit magnitude as med, producing an overall grade of C+ (5.7/10). Approved in >30 countries (not US).
- What safety findings are reported for Thymosin alpha-1?
- Thymosin alpha-1 has a low risk profile in the database. Low (well-tolerated in trials; injection site reactions) Legal status: Rx in EU, Asia, Russia (Zadaxin); NOT FDA-approved in US; Category 2 on 503A bulks — compounding prohibited as of Jan 2025.
- What doses or routes are reported for Thymosin alpha-1?
- 1.6 mg subQ 2x/week (hepatitis indications); biohacker dosing similar This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
- How does Thymosin alpha-1 work?
- 28-amino-acid peptide derived from thymus prothymosin alpha; stimulates TLR9/Th1 immunity; activates dendritic cells and T-cell maturation; used in Europe/Asia for hepatitis B/C, sepsis, as vaccine adjuvant
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.