Thymosin Alpha-1
Also known as Tα1 · Thymalfasin · developed by SciClone
Large randomised trials in humans are complete or under way, but the compound is not licensed. Efficacy and common adverse effects are reasonably well characterised; long-term safety may not be.
What it is
A 28-residue peptide originally isolated from thymus tissue, with a genuine clinical history — approved in a number of countries, though not in the UK, EU or US.
How it is thought to work
Modulates immune function through effects on toll-like receptor signalling, T-cell maturation and dendritic cell activity.
What the studies found
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Approved for hepatitis B in several countries
Licensed in over 30 countries, largely for chronic hepatitis B and as a vaccine adjuvant, on the basis of randomised trials.
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Studied in sepsis and in COVID-19
Trials in sepsis and observational work during COVID-19 produced mixed results. No indication was established in Western regulatory markets.
What the evidence does not show
- Not approved in the UK, EU or US, despite a long development history — an important signal about how those regulators assessed the evidence.
- Trial quality is variable and much of it is older.
- Claims about general immune enhancement in healthy people are not supported by the trials, which studied specific disease populations.
Reported risks and adverse effects
- Generally well tolerated in trials; injection site reactions are the most common effect.
- Immune modulation carries theoretical concern in autoimmune disease.
- Its safety record comes from supervised clinical use in defined patient groups.
This is a summary of what has been reported in the literature, not a complete safety profile. For anything concerning your own health, speak to a doctor.
Regulatory status
Licensed in a number of countries including parts of Asia and Latin America. Not approved in the UK, EU or US.