Educational guide
Thymulin Dosage Protocol - Peptide Dosages
Thymulin (5 mg) Dosage Protocol A zinc-dependent thymic nonapeptide (formerly “serum thymic factor”/FTS), studied since the 1970s in T-cell immunology. Research-use-only — not an approved medicine and not the same molecule as Thymalin. This page is an educatio
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Thymulin (5 mg) Dosage Protocol
A zinc-dependent thymic nonapeptide (formerly “serum thymic factor”/FTS), studied since the 1970s in T-cell immunology. Research-use-only — not an approved medicine and not the same molecule as Thymalin. This page is an educational reference, not a dosing recommendation.
Why Thymulin draws research interest
These are the directions researchers and the peptide community most often explore Thymulin for — so you know you’re in the right place. They describe what is being studied, not proven benefits, approved uses, or promised results.
Zinc is part of the molecule, not a cofactor you add later
What makes thymulin unusual is that its biological activity is strictly zinc-dependent. Binding studies show the nonapeptide binds a single zinc ion with sub-micromolar affinity, and NMR and antibody work show the zinc gives the peptide a specific folded conformation that zinc-free thymulin does not have. Remove the zinc and you have the same amino-acid sequence with none of the activity. This is why the peptide is described as a zinc-metallopeptide rather than simply "a peptide that works better with zinc."
Thymulin is a defined molecule; Thymalin is a mixture
This is the single most important thing to understand before reading anything about "thymic peptides." Thymulin is one chemically defined nonapeptide with a known sequence. Thymalin is a crude polypeptide extract prepared from thymus tissue — an undefined mixture of many peptides. They are not interchangeable, they do not have the same evidence base, and a vendor using the two names loosely is not describing the same product. Our separate Thymalin page covers the extract; this page covers the defined peptide.
A genuine, well-documented human link: zinc status
One part of the thymulin story is unusually well grounded in human data. In carefully controlled studies of mild zinc deficiency, serum thymulin activity fell and then recovered when subjects were given zinc — making thymulin activity a sensitive readout of zinc status and tying thymic hormone function to a common nutritional variable. That is a real, reproducible finding about the endogenous hormone. It is not the same as evidence that injecting a research vial of synthetic thymulin produces a health benefit, and the honest reading keeps those two ideas separate.
Evidence ranges from early laboratory work to clinical trials depending on the use — the sections below cover the actual data and sources.
Mix & measure Thymulin · 5 mg
Pre-filled with this protocol’s recommended BAC water and documented starting dose — edit any field to run your own numbers.
Reconstitution math only — not dosing advice. U-100 syringe: 100 units = 1 mL. Full reconstitution guide → · Advanced calculator →
A zinc-bound thymic nonapeptide that promotes T-lymphocyte differentiation and modulates T-cell subset functions. The zinc ion is not optional: without it the peptide loses its characteristic three-dimensional conformation and its biological activity.
A laboratory research peptide, not a drug. It is not approved for human use, has no established dose, and is distinct from the crude thymus extract sold as "Thymalin". The wellness/anti-aging claims attached to research vials are not backed by modern controlled human trials.
The solid science is decades-old immunology: thymulin induces T-cell markers, its serum level falls in human zinc deficiency and rises again with zinc repletion, and it declines with age as the thymus involutes. Therapeutic benefit in humans was never established.
Quickstart Highlights
Thymulin is a zinc-dependent nonapeptide hormone produced by the epithelial cells of the thymus — sequence pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn. It was first characterized in the 1970s as the “facteur thymique sérique” (serum thymic factor, FTS) by Jean-François Bach and Mireille Dardenne at Hôpital Necker in Paris, and later renamed thymulin once it was recognized that the peptide is biologically active only when it is coupled to a zinc ion[1][2].
This page is an educational reference on what thymulin is, what the research literature actually shows, and how a lyophilized research vial is reconstituted to a known concentration. It is not medical advice and not a protocol to administer the peptide. Thymulin is not approved by the FDA or any regulator as a therapeutic. One point matters up front: thymulin is not the same product as “Thymalin.” Thymulin is a single, chemically defined zinc-bound nonapeptide, whereas Thymalin is a crude polypeptide extract of thymus tissue — a mixture, not a molecule. They are routinely confused because the names look alike; this reference is about the defined peptide.
A thymic nonapeptide (pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn) from thymic epithelial cells whose activity requires a bound zinc ion[1][3]. Formerly called serum thymic factor (FTS).
2 mL bacteriostatic water per 5 mg vial → 2.5 mg/mL. This is a lab-handling reference only; the site provides no dose for administration.
Not FDA-approved for any use. Studied for decades as an experimental immunoregulator, but never developed into an approved drug. No validated human protocol exists.
Historical immunology + animal research. Its T-cell-differentiating activity, zinc dependence and age-related decline are well documented[1][4]; there are no modern controlled human efficacy trials supporting the wellness claims made for grey-market vials.