Thymulin and zinc
The experiment that linked activity to zinc, Dardenne and colleagues, PNAS, 1982. Researchers removed metals from serum thymic factor and lost activity in a cell test. Zinc restored it; the authors named the active form thymulin. It wasn’t a treatment trial.
Interactions between zinc and thymulin, Dardenne and Pleau, Metal-Based Drugs, 1994. A review explaining the nine-amino-acid peptide and its zinc partner. Useful for understanding the mineral’s role.
Serum thymulin in human zinc deficiency, Prasad and colleagues, Journal of Clinical Investigation, 1988. A small study found low thymulin activity despite normal blood plasma zinc. Restoring zinc restored activity. The intervention was zinc, not thymulin treatment.
Thymulin in animal research
Thymulin gene therapy in mice with asthma, da Silva and colleagues, Science Advances, 2020. Genetic instructions helped cells make thymulin, and established lung problems improved. The mice and the gene-delivery method are essential parts of the finding.
Physiology and therapeutic potential of thymulin, Reggiani and colleagues, Current Pharmaceutical Design, 2014. Wider background on thymulin, including gene research in rodents. It doesn’t settle human treatment questions.
Thymosin alpha-1 in people
The thymosin alpha-1 literature review, Dominari and colleagues, World Journal of Virology, 2020. Background on the molecule, clinical studies and reactions such as injection-site redness or discomfort. That doesn’t establish a general benefit.
The larger sepsis trial, Wu and colleagues, BMJ, 2025. Adults received thymosin alpha-1 or placebo, with no clear reduction in deaths over 28 days. The funder was SciClone Pharmaceuticals, maker of the thymalfasin medicine Zadaxin; some authors received company grants or fees.
FDA approval and safety questions
FDA answers questions about compounding, including why these medicines have no FDA approval.
On FDA’s safety page, the withdrawn-nominations table includes thymosin alpha-1. Its April 22, 2026 content date tells you when the page was current, not when an individual nomination was withdrawn. The warnings remain; withdrawal isn’t clearance.
FDA’s December 2024 briefing summarizes foreign label warnings, including the Italian Zadaxin label’s prohibition during pregnancy and breastfeeding. It isn’t U.S. prescribing information; no U.S. label exists.