Nonathymulin (INN), FTS, FTS-Zn, zinc-thymulin, serum thymic factor, facteur thymique sérique
A nine-amino-acid hormone made by the epithelial cells of the thymus, the gland that trains immune T cells. It only works when it holds a zinc ion, which is why blood thymulin activity falls when someone is short of zinc and recovers when zinc is replaced.
None of these uses is approved. Uses tested in people come first, then claims that rest on animal studies or user reports.
Trial: tested in people, with the result. Animal: cell or animal studies only. Community: reported by users, not studied.
Every compound’s uses, by body system: evidence map, and by condition: conditions A to Z.
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Thymulin is made by the epithelial cells of the thymus, the gland where immune T cells are trained, and it only becomes active when it holds a zinc ion. In the laboratory it nudges immature T cells toward maturity and shifts the balance of T-cell subsets. In rats and mice it damps inflammatory signals, including interleukin-1 and the NF-κB switch that turns inflammation on, which is how its pain-relieving effects in animals are explained. Its production is steered by pituitary hormones, and it falls with age.
AnimalMainly from cell and animal studies; not shown in people.
No receptor for thymulin has been identified. The 1987 arthritis trials saw clinical improvement without clear changes in immune blood tests, so how it helped, if it did, is unexplained.
Amor 1987
1, 5 or 10 mg a day in two randomized placebo-controlled trials in rheumatoid arthritis, where 5 mg a day did best. The published abstract gives neither the route nor the length of treatment.
Dokhelar 1983
10 mcg per kg into a vein every 3 days, in a 4-person study that measured natural killer cell activity.
No established dose for the immune and anti-aging uses it is now sold for. Public guides describe microgram amounts under the skin, scaled from animal work, which is 1,000 times smaller than the milligram doses used in the human trials.
No set cycle, shown over 26 weeks
The ways Thymulin is most often run, each tagged with where it comes from.
Two randomized, double-blind, placebo-controlled trials in Paris, 1987. 56% rated improved against 17% on placebo, with minimal side effects.
40 matched patients, randomized against placebo. No difference on three disability scales, and no significant side effects.
Four people with cancer, 1983. Activity rose in the 2 who started low and fell in the 2 who started normal or high.
Scaled from animal studies, roughly a thousandfold below the doses used in the human trials. Nothing supports it.
10 mcg/kg. 10 mcg per kg into a vein every 3 days in a 4-person study of natural killer cell activity (Dokhelar 1983). Not a subcutaneous dose, and the paper doesn’t describe the patients’ ages.
The multiple sclerosis trial injected it under the skin; the earliest studies gave it into a vein in hospital. Community use is subcutaneous injection with rotating sites.
No published guidance, and no established schedule to miss a dose from.
On 5 mg a day, 56% of patients were rated improved against 17% on placebo, with four objective measures also favoring treatment; blood immune measures didn’t clearly change.
TrialNo difference from placebo in disability, walking or function in 40 patients, followed another 6 months.
TrialIn a 1982 report of 3 children with antibody and T-cell defects, infections became less frequent and IgA appeared or rose; stopping the treatment reversed the change.
TrialNothing is known. No study has given thymulin to healthy adults for these purposes.
CommunityMinimal side effects (two randomized arthritis trials)
The 1987 report says only that adverse effects were minimal, without listing them.
No significant side effects (40 patients, 6 months)
From the multiple sclerosis trial, which injected it under the skin for half a year.
Immune measures moving in unexpected directions
In the 1983 study, natural killer activity rose in people who started low and fell in people who started normal or high.
Unknown with long use or at the doses sold today
The trials were short, small and decades old, and used amounts about a thousand times larger than those quoted in current guides.
Injection-site pain, redness or infection (unregulated vials)
Use sterile technique. Spreading redness, heat or pus needs medical care.
Hives, swelling of the face or throat, or trouble breathing after an injection: stop and get medical help. A hot, spreading red injection site with fever needs urgent care.
The side effects people ask about most, answered one by one. Each answer says where it comes from.
Trial: reported in human studies. Not reported: studied in people and not reported. No data: no human safety data. A side effect that hasn’t been reported can still happen, especially with long or high-dose use. Any of these across every compound: the side-effect finder.
No product label covers thymulin, so these come from human studies and from precautions based on how it works. Most important first.
Trial: seen in human studies, or a group those studies left out. Precaution: follows from how it works or from a related drug, and hasn’t been tested. This isn’t a complete list: a pharmacist or doctor can check a specific medicine or condition. Every documented interaction, by medicine: drug interactions.
What’s known about pregnancy, breastfeeding, kidney and liver problems, age and surgery. Where nothing has been studied, the row says so.
Trial: from human studies. Precaution: not studied, so the caution follows from how it works or from a related drug. Ages are given as approved or studied; this site never gives doses for children. Across every compound: pregnancy, breastfeeding, kidney disease, liver disease, older adults and surgery.
Both are thymus peptides sold for immune support, and both get called “thymic hormones”, but they are different molecules and have never been tested together.
4 key published human studies, with how many people took part. Animal studies aren’t listed here.
5 mg a day did best: 56% of patients were rated improved against 17% on placebo (p<0.02), with four objective measures also favoring treatment, minimal adverse effects and no clear change in immune measures.
Amor et al., Ann Rheum Dis 1987, PMID 3310925
No significant difference from placebo in Kurtzke disability score, ambulation index or functional scale in people with worsening multiple sclerosis, and no significant side effects.
Roullet et al., Acta Neurol Scand 1989, PMID 2618585
Natural killer activity rose in the 2 patients whose starting activity was low and fell in the 2 whose starting activity was normal or high.
Dokhelar et al., Int J Immunopharmacol 1983, PMID 6195118
Infections became less frequent and less severe, cell-mediated immunity tests improved, and IgA appeared in the 2 children who had none; interrupting treatment reversed the gains in 2 children.
Bordigoni et al., Lancet 1982, PMID 6124716
No ongoing trial of thymulin is registered, and none has finished recently without publishing its results. Checked on ClinicalTrials.gov, October 7, 2026. Every compound: trials under way.
The human evidence is three small published studies from the 1980s: two randomized placebo-controlled trials in rheumatoid arthritis that favored 5 mg a day, a 40-patient randomized trial in multiple sclerosis that found nothing over 6 months, and a 4-patient intravenous study. The arthritis paper survives only as an abstract, so its size, route and duration are unknown. Development stopped, nothing has been registered since, and nobody has studied the microgram doses sold today, long-term use, or healthy adults.
Sold as a powder vial of unregulated research chemical, usually labeled thymulin or zinc-thymulin. Nothing checks the amount or whether the zinc is present, and the zinc is what makes the hormone work. Vial Guide gives no mixing or dose figures, because the trial doses and the amounts sold online differ by about a thousandfold.
Every compound side by side: the half-life chart and the storage chart.
Every compound’s numbers: the identifiers table.
Only works holding a zinc ion, and nothing checks whether a vial sold as thymulin or zinc-thymulin contains it. Different from Thymalin, a Russian calf-thymus extract, and from thymosin alpha-1, though vials and guides confuse the names.
A nine-amino-acid hormone made by the epithelial cells of the thymus, the gland that trains immune T cells. It only works when it holds a zinc ion, which is why blood thymulin activity falls when someone is short of zinc and recovers when zinc is replaced.
Thymulin is made by the epithelial cells of the thymus, the gland where immune T cells are trained, and it only becomes active when it holds a zinc ion. In the laboratory it nudges immature T cells toward maturity and shifts the balance of T-cell subsets. In rats and mice it damps inflammatory signals, including interleukin-1 and the NF-κB switch that turns inflammation on, which is how its pain-relieving effects in animals are explained. Its production is steered by pituitary hormones, and it falls with age. No receptor for thymulin has been identified. The 1987 arthritis trials saw clinical improvement without clear changes in immune blood tests, so how it helped, if it did, is unexplained.
Not approved as a drug in the US, the EU or anywhere else. It holds an international nonproprietary name, nonathymulin, from its 1980s development as a drug, but that development stopped and no trial has been registered since (ClinicalTrials.gov, October 2026). Thymulin acetate is in Category 3 of FDA’s 503A bulk drug substances list, nominated for pharmacy compounding without enough supporting information for FDA to evaluate it. It was in Category 3 in the September 2023 list and is still there in the May 14, 2026 update. It is not on the 503B list for outsourcing facilities.
From human studies (Amor 1987): 1, 5 or 10 mg a day in two randomized placebo-controlled trials in rheumatoid arthritis, where 5 mg a day did best. The published abstract gives neither the route nor the length of treatment. Dokhelar 1983: 10 mcg per kg into a vein every 3 days, in a 4-person study that measured natural killer cell activity. These are the amounts sources reference, not recommendations.
No product label covers thymulin, so these come from human studies and from precautions based on how it works. Pregnancy or breastfeeding: No human safety data in pregnancy, and the 1980s trials excluded this question entirely. Autoimmune disease, without medical advice: It alters T-cell balance. It improved rheumatoid arthritis in two trials but did nothing in multiple sclerosis, so the direction of effect in a given autoimmune disease isn’t predictable. Anyone on immune-suppressing drugs: Transplant and autoimmune patients depend on a suppressed immune system; a thymic hormone that pushes T-cell maturation has never been studied alongside those drugs. The “Who should avoid it” section lists 2 more groups.
Before mixing: Freezer (−20 °C) for long-term storage, kept dry and dark. After mixing: Fridge (2–8 °C) once in solution. This is common practice; no product label covers it.
Probably. Not named in the 2026 List. S2 names growth hormone, its releasing factors and thymosin beta-4, not the thymic nonapeptides, so thymulin falls under S0 non-approved substances: no health authority has approved it, which makes it banned at all times.
Yes. The human studies section lists 4 published studies. Among them, from 1987: 5 mg a day did best: 56% of patients were rated improved against 17% on placebo (p<0.02), with four objective measures also favoring treatment, minimal adverse effects and no clear change in immune measures.
Trial 6 months of injections in 40 people with multiple sclerosis, followed another 6 months.
Trial Injected: under the skin in the multiple sclerosis trial, into a vein in the earliest studies. No oral, nasal or skin form has been tested; animal lung studies delivered the gene, not the peptide.
No study No data. No study has looked at thymulin and alcohol together.
No study No study has combined them. No interaction is known, but none has been looked for.
Trial No label and no overdose data. Trials used up to 10 mg a day without reported harm, but nothing is established. Call Poison Help (1-800-222-1222), or emergency services for severe symptoms.
For the protocol details
For how it works, who should avoid it and the limits of the evidence
For uses, the side-effect questions, special situations, trials, identifiers and status outside the US
Doses tagged Community come from public dosing guides and user reports, checked against at least two of them. Those sites aren’t named here because many of them sell peptides or earn commissions on them.