Thymosin α1
Thymalfasin, an N-acetylated 28-residue peptide
A peptide first isolated from the thymus, studied for its role in T-cell maturation. As thymalfasin it is licensed as a medicine in some countries outside the US, UK and EU, mainly for hepatitis B.
Structure
A 28-residue, strongly acidic peptide originally isolated from thymus tissue, acetylated at the N-terminus. Select any residue to see what it is.
Evidence at a glance
Where the published research on Thymosin α1 comes from, by type of study.
Cell studies
T-cell and dendritic cell maturation, toll-like receptor signalling.
Animal studies
Infection, vaccine response and tumour models in mice.
Human studies
Clinical trials of thymalfasin in hepatitis B, sepsis and as a vaccine adjuvant, with mixed results.
Research areas
What laboratories have studied Thymosin α1 for, and in which models. These are research questions, not proven uses.
T-cell maturation
Human immune cell culture- Promotes maturation of T cells and dendritic cells in vitro.
- Acts through toll-like receptors on immune cells.
Infection and vaccines
Mouse infection modelsVaccine studies- Studied as an adjuvant to boost vaccine responses.
Legal status
Thymosin α1 is not an approved medicine anywhere we cover. Suppliers may sell it for laboratory research only, and regulators judge that by the whole website, not the label.
United States Not approved
Not FDA-approved. It has orphan-drug designations for some conditions, which is not approval.
United Kingdom Not licensed
No MHRA licence. Sold with medicinal claims it counts as a medicine under the Human Medicines Regulations 2012.
European Union Not authorised
No EMA authorisation. Under Directive 2001/83/EC a substance can be a medicine by function, whatever its label says.
Sport Check S0
Not approved for human use, so it falls under WADA's S0 non-approved substances class. Check the current list.
Lab handling
General good practice for research materials. Follow the supplier's datasheet where it differs.
Storage
Keep the sealed material at −20 °C, dry and away from light. Let the vial reach room temperature before opening to stop condensation.
Solubility
Soluble in sterile water or buffer. Add solvent down the vial wall and swirl gently rather than shaking.
Aliquots
Split solutions into single-use aliquots, label with lot number and date, and freeze. Avoid repeated freeze-thaw cycles.
Work out your stock solution
Stock concentration, molarity and dilutions for Thymosin α1, using MW 3108.28 g/mol.
Before you buy for your lab
Tick each check as you confirm it with the supplier. Do not order until all six are done.
Questions researchers ask
What is Thymosin α1?
A peptide first isolated from the thymus, studied for its role in T-cell maturation. As thymalfasin it is licensed as a medicine in some countries outside the US, UK and EU, mainly for hepatitis B.
What is the molecular weight of Thymosin α1?
About 3108.28 g/mol for the free peptide. Salt forms such as acetate weigh more, so use the figure on your batch certificate of analysis.
Is Thymosin α1 approved for human use?
No. Not FDA-approved. It has orphan-drug designations for some conditions, which is not approval.
How should Thymosin α1 be stored in the lab?
Keep the sealed material cold, dry and away from light, typically at −20 °C. Once in solution, split it into single-use aliquots and freeze to avoid repeated freeze-thaw cycles.
Does this page give doses?
No. We publish laboratory and educational information only, never doses, injection guidance or treatment advice.
Is thymosin alpha-1 legal in the US?
It is not FDA-approved, although it has orphan-drug designations for some conditions, which is not approval. Research material may be sold for laboratory use only.
Is thymosin alpha-1 legal in the UK?
Thymosin α1 it is not licensed by the MHRA. Selling it with medicinal claims makes it an unlicensed medicine under the Human Medicines Regulations 2012, so UK suppliers can only offer it for laboratory research.
Thymosin alpha-1 vs thymosin beta-4: what is the difference?
Despite the similar names they are different proteins. Thymosin α1 is a 28-amino-acid peptide studied for immune modulation. Thymosin β4 is a 43-amino-acid actin-binding protein, and TB-500 is a fragment of it. See our TB-500 profile or the full thymosin α1 vs β4 comparison.
What is the half-life of thymosin alpha-1?
Published pharmacokinetic studies of thymalfasin report a plasma half-life of about 2 hours after subcutaneous administration.
Is thymosin alpha-1 approved anywhere?
Thymalfasin is licensed as a medicine in some countries outside the US, UK and EU, mainly for hepatitis B. It is not licensed in the US, UK or EU.
Is thymosin alpha-1 banned by WADA?
It is not approved in WADA-recognised major jurisdictions, so athletes should treat it as falling under the S0 non-approved substances class.
