Summary
Thymulin is a nine-residue hormone secreted by thymic epithelial cells that needs zinc to be active. It influences T-cell differentiation and has two-way interactions with the neuroendocrine system. Blood levels fall with age and with zinc deficiency.
Structure
pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn. Biologically active only when bound to zinc.
How it works
Zinc-bound thymulin promotes T-cell maturation markers and modulates cytokine release. Its secretion is itself regulated by hormones including prolactin, growth hormone and thyroid hormones.
Research use cases
Areas where Thymulin has been studied. Inclusion here does not mean it works for that purpose.
- T-cell development
- Neuroendocrine–immune interaction
- Inflammatory pain and neuroinflammation models
What the research found
Neuroendocrine control
A major review describes how hormones and neuropeptides control thymulin secretion and how thymulin in turn feeds back on the pituitary.1
Safety and open questions
No controlled human data.
Regulatory status
Not approved. Research compound.
Status was accurate when this page was last reviewed on October 26, 2026. Regulations change; check with the relevant authority before relying on it.
Thymulin: common questions
Why does thymulin need zinc?
Zinc binding changes the peptide’s shape into its active conformation. Zinc deficiency lowers measurable active thymulin.
Is Thymulin approved for human use?
Not approved. Research compound.
References
- Savino W, Dardenne M. (2000). Neuroendocrine control of thymus physiology. Endocrine Reviews.
Links open a PubMed search for the exact title, or the original source where one is given.