Research library
Immune & ThymicMaturing human RCT base
Zadaxin / Thymalfasin
Thymosin Alpha-1, 28-aa thymic peptide
A 28-amino acid thymic peptide that modulates innate and adaptive immunity via TLR signaling, one of the most clinically tested peptides in existence.
28
35+
>11,000
How Thymosin Alpha-1 works
A thymic peptide that tunes the immune system, strengthening antiviral T cell responses while also calming overactivity. The most clinically tested peptide in this library.
Thymosin α1
TLR2 / TLR9
T cell balance
Immune modulation
Research applications
Chronic hepatitis B
Antiviral immune adjunct
Immune reconstitution
Adjunct therapy
Sepsis
Immune modulation
Bars indicate how far the evidence has progressed (in vitro to animal to human), not the size of any effect.
Molecular profile
Key studies
The efficacy of thymosin in the treatment of chronic hepatitis B virus infection: a meta-analysis
Chan HL, Tang JL, Tam W, Sung JJ
Pooled across 5 RCTs (353 patients), thymosin roughly doubled the sustained virological response vs control (OR 2.67) at 12 months post treatment.
Evidence, safety & status
Claimed benefits & evidence
One of the most clinically tested peptides in existence, >30 trials, >11,000 subjects, post marketing surveillance of >600,000 patients; approved in 35+ countries for chronic hepatitis B/C and as an immune adjunct. Hepatitis B data is strongest. Sepsis data is mixed (the large 2025 TESTS trial is the strongest controlled evidence). Anti aging/general immune support use has no RCT.
Safety & dangers
Among the cleanest safety profiles of any peptide, a 2024 review found it safe and well tolerated across all indications, with no significant treatment related adverse events at therapeutic doses.
Contraindications
Caution in immunosuppression for organ transplant (immune activation) and in autoimmune disease.
Regulatory status
Never FDA approved despite global use. Category 2 (Sept 2023); nomination withdrawn Sept 2024; PCAC voted against 503A inclusion (Dec 2024) despite arguably the strongest human evidence on the list. WADA: S0/related.
Source: Fnx Performance Peptide Research Database, a synthesis of the scientific and regulatory literature, not medical advice. For medical questions, consult a qualified physician.
For research use only
For Research Use Only. Not for human or animal consumption. Products are sold strictly for in vitro laboratory research, not for compounding or therapeutic application.