Thymulin
Thymulin (Facteur Thymique Serique, FTS-Zn, Serum Thymic Factor)
This peptide has not been evaluated by the FDA. It is sold as a research chemical and has no regulatory status for human use.
A natural hormone produced by the thymus gland that requires zinc to function and plays an essential role in developing immune cells (T-cells) and building the immune system. It has also shown anti-inflammatory and pain-relieving effects in animal studies, but has never been tested in human clinical trials.
This entry is a cited research summary, not an established treatment reference. Dosing language is included as source context, not as medical instruction.
Safety Summary
In animal studies, low nanogram doses of thymulin administered locally (intraplantar) or systemically (intraperitoneal) produced hyperalgesia via PGE2-dependent mechanisms (PMID 17192563). At higher microgram doses, thymulin and its analogue PAT showed anti-inflammatory and analgesic effects without significant adverse effects (PMID 17192563). The 2025 review of thymic peptides noted that an important feature of thymus preparations is their therapeutic safety -- even long-term use does not cause side effects (DOI 10.1007/s10989-024-10666-y). The FDA FAERS database returned no adverse event reports for thymulin. In the topical zinc-thymulin hair loss application, community data reports no adverse systemic effects or local side effects across 3,300 applications (online communities/HairlossResearch). However, formal human safety data for exogenous thymulin injection is entirely lacking because thymulin has never entered clinical trials.
Clinical check-in
If real-world use or exposure is being considered, review potential interactions, contraindications, and monitoring needs with a licensed clinician rather than relying on summary copy alone.
Sources: [1-10]