What is THYMALIN?
Thymalin is classified as a peptide bioregulator, belonging to the family of tissue-derived polypeptide complexes historically isolated from thymic tissue. Unlike a synthetic single-sequence peptide, Thymalin is a standardized mixture of low-molecular-weight polypeptides; for this reason it is characterized as a defined complex rather than by a discrete molecular formula, molecular weight, or amino-acid sequence. It carries the identifier CAS 79621-14-0 and is supplied as a lyophilized (freeze-dried) powder.
Because Thymalin is a polypeptide fraction and not a single molecule, its identity is established at the level of the standardized complex — the reproducible peptide profile of the preparation — rather than through a single-chain primary structure. This places it within the broader class of "peptide bioregulators" alongside short defined peptides, but it is distinguished by its composite, multi-peptide nature. Each production lot is standardized to a consistent profile so that the reference material behaves reproducibly across experiments.
In the scientific literature, Thymalin is associated with in-vitro and preclinical research into thymic-derived peptides and immunological signaling models. American Peptides supplies Thymalin strictly as a research reference material for in-vitro and laboratory investigation. No physiological, therapeutic, or performance outcomes are described, claimed, or implied, and the material is not intended for human or veterinary use, diagnosis, or treatment.
Reconstitution & handling
Thymalin is provided as a lyophilized powder that must be reconstituted before use in the laboratory. It is soluble in bacteriostatic water, which is the commonly used solvent for hydrating this class of thymic polypeptide complex; researchers should consult the lot-specific Certificate of Analysis for any solvent recommendations particular to a given batch. To dissolve, the solvent is directed slowly against the inner wall of the vial rather than onto the powder directly, and the vial is then allowed to stand and swirled gently until a clear solution forms. Vigorous shaking, vortexing, or foaming should be avoided, as mechanical shear and air-liquid interfaces can degrade peptide material.
As with peptide reference materials generally, reconstitution should be performed under clean conditions using sterile technique, and the resulting solution handled promptly. Solubility and clarity should be confirmed visually; a properly reconstituted preparation appears clear and free of visible particulates. This handling guidance addresses solvent chemistry and dissolution only and does not constitute any use, administration, or dosing instruction.
Storage & stability
In its lyophilized form, Thymalin is stored at -20°C and protected from light and moisture, conditions under which the freeze-dried complex is most stable for long-term storage. Vials should be kept tightly sealed and, where practical, desiccated to limit moisture uptake, which can compromise peptide integrity. After reconstitution, the solution should be refrigerated at 2-8°C and used within a short working window; repeated freeze-thaw cycling is discouraged, and preparing single-use aliquots is preferable to minimize degradation of the reconstituted material.
How it's tested
Identity and purity of Thymalin are verified analytically and documented on a lot-specific Certificate of Analysis (COA), which is available for the material. Purity is established at ≥99% by high-performance liquid chromatography (HPLC), which resolves the peptide profile and quantifies related components. Because Thymalin is a standardized polypeptide complex rather than a single molecule, characterization emphasizes reproducibility of the established peptide profile across lots, with complementary mass spectrometry (MS) used to confirm the peptide composition where applicable. The COA provides the traceable analytical record documenting that each lot conforms to specification.