Thymulin has an unusually old and unusually specific human record. In the 1980s a French group made a synthetic version of the thymus hormone, called it nonathymulin, and tested it against placebo at three fixed daily amounts in rheumatoid arthritis. Those trials are the only published comparison of doses, and nothing registered since has added to them. This page reports what the trials and the regulators' databases state (all opened 2026-11-02), converts the figures to vial arithmetic, and records what the record leaves out. It reports figures; it suggests none.
The compound's reconstitution calculator works any vial and water volume, the peptide dosage chart holds the one-line version beside every other compound, and the two other thymus-derived substances on this site have their own pages: thymosin alpha-1 and thymalin.
What thymulin is
The thymus releases a small peptide called facteur thymique sérique, serum thymic factor, which is inactive on its own and becomes active when it binds a single zinc ion. The zinc-bound form is thymulin. PubChem lists the peptide as C33H54N12O15 with a molecular weight of 858.9 g/mol (CID 71300623, CAS 78922-62-0). The prefix in "nonathymulin", the name the trials used, refers to the nine residues of the synthetic chain.
The zinc dependence has a practical consequence for reading any figure. A research vial is labelled by the mass of peptide it holds. Whether that peptide is zinc-bound, partly bound or not bound at all is not stated by a milligram figure, and the activity the trials measured was that of a defined pharmaceutical preparation.
What the trials state
| Study | Population | Amounts | Design | Result |
|---|---|---|---|---|
| Amor et al., Ann Rheum Dis 1987 (PMID 3310925) | Rheumatoid arthritis | 1, 5 and 10 mg a day against placebo | Two randomised, double-blind, placebo-controlled trials | 5 mg reported as most efficient: 56% globally improved v 17% on placebo, p < 0.02; minimal adverse effects |
| Amor et al., Arthritis Rheum 1984 (PMID 6362675) | Rheumatoid arthritis | Not stated in the record | Short report, no abstract | — |
| Faure et al., Clin Exp Rheumatol 1987 (PMID 3427844) | Rheumatoid arthritis | Not stated in the record | Open trial with immunological follow-up | No abstract indexed |
| Roullet et al., Acta Neurol Scand 1989 (PMID 2618585) | Multiple sclerosis, 40 matched patients | Not stated in the abstract | Randomised, double-blind, subcutaneous, 6 months treated + 6 followed | No difference from placebo; no significant side effects |
The 1987 paper is the one that matters for dosing, because it set three amounts against each other rather than testing one. Its abstract reports that 5 mg outperformed both the lower and the higher amount, that the effect came with minimal adverse effects, and that it was not accompanied by clear changes in the immunological measures, although response correlated with an imbalance in T-cell subsets. The abstract does not state the route or the length of treatment; the full text sits in PubMed Central as a scanned 1987 article and was not retrieved for this page, so those details are left unreported here rather than assumed.
The multiple sclerosis pilot is the only other controlled study and its result was negative: six months of subcutaneous treatment made no measurable difference to disability.
The figures on vendor pages are of a different order. This site's dosage chart recorded them on 2026-09-18 as 250 to 750 mcg subcutaneously a day in blocks of 10 to 20 days, citing no study. The smallest trial amount, 1 mg, is 1.3 to 4 times that range, and the amount the trials favoured, 5 mg, is 6.7 to 20 times it.
What the databases hold today
PubMed returned 374 records with thymulin in the title or abstract on 2026-11-02. Seven carry the clinical-trial tag, and most of those are nutrition studies that measure the body's own thymulin, for example a 1993 study in which zinc supplementation restored plasma zinc and thymulin in patients with Crohn's disease (PMID 8364132). They give zinc, not thymulin, and their figures are not doses of the peptide.
ClinicalTrials.gov returned one record for the word: NCT01229579, a completed zinc-supplementation study of polio-vaccine response in infants in Pakistan. It does not administer thymulin. No registration anywhere gives it.
DailyMed returned one US listing: a homeopathic pellet, Thymuline (nonathymulin) by Homeocare Laboratories, whose active ingredient is "Thymulinum 9C" and whose stated purpose is "immune support". A 9C homeopathic dilution is a 1-in-100 dilution repeated nine times, one part in 10^18. At that dilution a tube of pellets holds no measurable peptide, so the listing is a product name, not a source of a dose.
The arithmetic per vial
Research vials of thymulin are listed at 5 mg and 10 mg in this site's calculator data. The trial amounts are milligrams, so concentrations here are in mg/mL rather than the micrograms most peptides use.
| Vial and water | Concentration | 1 mg | 5 mg | 10 mg |
|---|---|---|---|---|
| 5 mg in 1 mL | 5 mg/mL | 20 units | 100 units | — |
| 5 mg in 2 mL | 2.5 mg/mL | 40 units | 200 units | — |
| 10 mg in 1 mL | 10 mg/mL | 10 units | 50 units | 100 units |
| 10 mg in 2 mL | 5 mg/mL | 20 units | 100 units | 200 units |
| 10 mg in 3 mL | 3.33 mg/mL | 30 units | 150 units | 300 units |
Units are on a U-100 syringe, where one unit is 0.01 mL; the insulin syringe units page shows how the barrels read. Any entry above 100 units is more than one full 1 mL syringe. That is the unusual feature of this compound: the middle trial amount, 5 mg, is an entire small vial, and the highest, 10 mg, an entire large one. Seen the other way, a 5 mg vial holds five of the 1 mg amounts and one of the 5 mg amounts; a 10 mg vial holds ten and two.
By molecule count, 5 mg of the peptide is about 5.8 micromoles. That figure is for the zinc-free chain PubChem lists; each active molecule also carries one zinc ion of about 65 g/mol, which a label in milligrams of peptide does not count.
What the figures omit
- The preparation. The trials used a pharmaceutical nonathymulin made for them. A research powder is a different product whose zinc content and purity are not stated by its label.
- Route and duration for the arthritis trials. Not in the indexed abstract and not reported here.
- Any replication. No trial since 1989 has given thymulin to people, and the positive arthritis result has not been repeated in the PubMed record.
- Any modern regulatory review. No approval, no US label for the peptide, no registered study.
What this page does not do
It states no amount for anyone to use and no schedule. It reports what three decades-old trials and today's databases state, each with its source and date, and does the unit arithmetic for the vial sizes in circulation. The compound is covered in Medibact's thymulin guide; mixing steps in general are on Medibact's how to reconstitute peptides page. Decisions about administering anything belong with a clinician.
Sources and dates
Opened 2026-11-02: PubMed abstracts and records for Amor B et al., Ann Rheum Dis 1987;46(7):549-54 (PMID 3310925); Amor B et al., Arthritis Rheum 1984;27(1):117-8 (PMID 6362675, no abstract); Faure GC et al., Clin Exp Rheumatol 1987;5(3):291-3 (PMID 3427844, no abstract); Roullet E et al., Acta Neurol Scand 1989;80(6):575-8 (PMID 2618585); Brignola C et al., Aliment Pharmacol Ther 1993 (PMID 8364132, title); PubMed searches thymulin[tiab] (374) and with clinical trial[pt] (7); ClinicalTrials.gov search "thymulin" (1 record, NCT01229579); DailyMed SPL search "thymulin" (1 listing, set id 1c3a713d-b6bf-4a3c-b7e2-93a3d80412b3, version 2, published 2019-03-01); PubChem CID 71300623. Vial sizes from this site's calculator data. Concentration, unit and molecule arithmetic by this site. Corrections go to the contact page.