Thymomodulin
An oral calf-thymus peptide mixture from Italy, tested in small trials on recurrent infections, allergy, asthma and ageing immunity
Thymomodulin is made by partly breaking down calf thymus tissue with acid, which leaves a mixture of peptides between about 1 and 10 kDa. Unlike most thymus extracts, which are injected, it was designed to work when swallowed. In the 1980s and early 1990s, mostly Italian groups tested it in children with recurrent respiratory infections and food allergy, in adults with asthma, rhinitis and chronic bronchitis, in elderly people and in a few other diseases. Most trials were small, several had no placebo, and none was repeated with modern methods. It is not approved in the US or the EU.
Used in human trials: 160 mg/day, Daily, Oral (Study: elderly people, neutrophil function) Details ↓
Recommended Dosing
Used in human trials
No manufacturer dose exists for this use: these are amounts given in published trials, not recommendations.
What is it?
Thymomodulin belongs to the family of thymus extracts that were popular in European medicine from the 1970s to the 1990s. The thymus, a gland behind the breastbone, is where T lymphocytes mature, and it shrinks with age. The idea behind these extracts was that peptides from the gland could support immune function where it was weak. Thymomodulin is an acid lysate of calf thymus made by an Italian manufacturer; its peptides range from about 1 to 10 kDa, and it has no single sequence or formula. Reviews from 1987 and 1989 single out one feature: unlike thymostimulin and other injected extracts, it was meant to stay active when taken by mouth.
The evidence that it is absorbed comes from a 1985 study in people over 70, whose blood normally shows no detectable activity of the thymic hormone FTS (thymulin). After a single oral dose, FTS-like activity appeared within hours, peaked at two to six hours and lasted longer at higher doses. That assay measured a biological effect in a rosette test, not the peptides themselves, so it shows something active reached the blood without saying what.
Laboratory work fits the label of an immune modulator. Thymomodulin induced a T-cell surface marker on mouse spleen cells, raised the release of GM-CSF and TNF in cultures of human lymphocytes and lung macrophages, increased macrophage HLA-DR expression, and enhanced phagocytosis by neutrophils. In cyclophosphamide-treated and aged mice it helped restore the antibody response. Standard mutagenicity tests were negative.
The clinical trials span recurrent respiratory infections in children and adults, food allergy with eczema in children, allergic rhinitis, asthma and bronchial hyperresponsiveness, chronic bronchitis, acute hepatitis B, early HIV infection, myocarditis and dilated cardiomyopathy, and immune markers in athletes and the elderly. Most report benefits: fewer infections or asthma attacks, fewer relapses on food challenge, lower IgE, better heart function. They also share weaknesses. Groups were small, often 10 to 50 people; several compared against the previous year or against untreated patients rather than a placebo; results were mostly published in Italian or in small journals; and no large confirmatory trial followed.
Thymomodulin is not on the US or EU medicines lists, and no trial of it is registered on ClinicalTrials.gov. A 2022 Cochrane review of immunostimulants for chronic bronchitis and COPD listed it among the products in its pooled trials, but its pooled results cover the whole class, not thymomodulin alone, so they are not credited to it here. What a reader can fairly take from the record is that an oral calf-thymus lysate was tolerated in small trials and produced measurable immune changes, while the clinical benefits it reported were never tested to modern standards.
Mechanism of Action
Thymomodulin is a mixture of small thymus peptides; in laboratory work it pushes immature T cells toward maturity and stimulates lymphocytes to release cytokines that in turn activate macrophages and neutrophils.
T-cell maturation
It induced a mature T-cell marker on mouse spleen cells, and after an oral dose elderly people's serum gained thymic-hormone-like activity of the kind that drives T-cell maturation.
Cytokines from lymphocytes
In human cell cultures it raised GM-CSF from lymphocytes and, with macrophages present, TNF; it did not act on macrophages alone.
Phagocyte activity
Neutrophil phagocytosis and intracellular killing rose in the laboratory and, in very old people after six weeks of treatment, in blood samples.
Published Research
These are studies of thymomodulin read from their PubMed abstracts: its absorption in elderly people, trials in children and adults with recurrent infections, allergy and asthma, small trials in other diseases, laboratory and animal work, and two reviews. Studies of TFX, a different Polish calf-thymus extract sometimes listed as 'TFX-thymomodulin', are not carded here, nor are class-wide reviews of immunostimulants.
Oral thymomodulin reaches the blood in old age
People over 70, who had no detectable serum FTS activity, developed FTS-like activity after one oral dose of thymomodulin. It peaked at 2 to 6 hours, persisted up to 12 hours and was gone by 48. Single doses from 80 to 800 mg were compared, and higher doses kept the activity up longer.
Neutrophil function restored in the very old
Elderly subjects averaging 85 years took 160 mg a day by mouth for six weeks. Neutrophil phagocytosis and the phagocytic index, both impaired at baseline, rose by about 133% and 113%. The oxidative burst measured by chemiluminescence rose 16%, which was not significant.
Fewer respiratory infections in children (double-blind)
In a double-blind trial in children with recurrent respiratory infections, those given oral thymomodulin had fewer infections per month than in the previous year and than the placebo group. Salivary IgA rose only in the treated group; routine blood and immune tests were otherwise unremarkable at baseline.
Second children's trial against placebo
Forty children aged 3 to 9 with recurrent respiratory infections the previous winter were randomised to thymomodulin (21) or placebo (19) for four months from October. The treated group had significantly fewer catarrhal episodes and better clinical ratings by parents.
Children with recurrent infections, untreated controls
Of 46 children with recurrent respiratory infections, 23 took thymomodulin and 23 were untreated controls. Only the treated children had a significant fall in infection frequency; interleukin-2 production did not change, so the immune basis of the benefit was not shown.
Chronic bronchitis: macrophage function and symptoms
Eleven adults with chronic bronchitis and repeated infections took 120 mg a day by mouth for six winter months. Their symptoms, days lost to illness and drug use improved, and superoxide production by macrophages recovered by bronchoalveolar lavage rose several-fold. No side effects were recorded. There was no control group.
Food allergy with eczema (double-blind)
Nineteen children with food allergy and atopic dermatitis followed an elimination diet for 90 days with thymomodulin 120 mg a day or placebo. Skin improved in both groups; on a two-week food challenge afterwards the skin held steady in the treated group and worsened with placebo, and total and specific IgE fell only with thymomodulin.
Food allergy relapses in 44 children
Children aged 7 months to 14 years with food allergy followed an exclusion diet for six months, half also taking oral thymomodulin. On oral challenge, symptoms returned in 29% of the treated group and 68% of the diet-only group, and were milder. IgE fell and IgA rose in the treated children.
IgE daily rhythm in atopic children
Twenty atopic and ten non-atopic children took thymomodulin at 3 mg/kg a day for 30 days. The day-night variation in serum IgE seen before treatment disappeared in the atopic children and was unchanged in the controls.
Perennial allergic rhinitis
Twenty patients took 120 mg a day for four months. Compared with the previous year, monthly attacks fell significantly, and IgE, skin-prick and RAST scores and eosinophil counts dropped while IgG rose. The comparison was historical, with no placebo arm.
Airway hyperresponsiveness in atopic asthma
Sixteen atopic asthmatics took thymomodulin 80 mg a day or placebo (eight each). Bronchial responsiveness to methacholine was significantly lower after 90 days on thymomodulin and stayed lower, though not significantly, 60 days after stopping.
Asthma attacks in children
Forty-one children aged 2 to 12 with asthma took the extract by mouth for three autumn months and again in March. Attacks averaged 6 per child in the same months of the previous year and 0.7 during the study. Immune tests were unchanged at first; a year later IgG and IgM were higher and IgE and complement lower. No side effects were seen, and there was no control group.
Acute hepatitis B (double-blind)
Fifty inpatients with acute hepatitis B received oral thymomodulin (26) or placebo (24) twice daily for 30 days. Liver enzymes fell faster and HBsAg cleared earlier on treatment, but only the ALT difference was significant. The CD4 to CD8 ratio rose in the treated group only.
More phagocytosis by neutrophils and macrophages
Incubated for an hour with thymomodulin at 100 to 400 micrograms per ml, rat macrophages and human neutrophils showed more phagocytosing cells, with a larger gain in the human cells. The phagocytic index itself did not change.
Cytokine release from human immune cells
In cultures of human lung macrophages and blood lymphocytes, thymomodulin raised TNF and GM-CSF but not interferon-gamma or interleukin-1. It raised GM-CSF from lymphocytes alone but had no effect on macrophages alone, suggesting it acts on lymphocytes first.
Macrophage HLA-DR and T-cell proliferation
With autologous lymphocytes present, thymomodulin increased the share of human lung macrophages expressing HLA-DR, though not their ability to drive T-cell proliferation. It added to T-cell proliferation driven by interleukin-2, PHA or anti-CD3 antibodies.
Antibody response restored in mice
Given daily to mice whose immunity had been suppressed with cyclophosphamide, thymomodulin sped recovery of the antibody response to sheep red cells and of white cell counts; antibody titres also returned to normal in immunosuppressed rabbits, with preliminary gains in aged mice.
No mutagenic activity
Thymomodulin was negative in a battery of mutagenicity tests: bacterial reverse mutation and yeast gene conversion with and without metabolic activation, mouse urinary and host-mediated assays, and a DNA-repair test.
Update on a thymic response modifier
Describes thymomodulin as a calf thymus acid lysate of peptides from 1 to 10 kDa with little or no toxicity in animals even at high doses. It regulated maturation of human and mouse pre-T cells, appeared to act mainly on T cells, increased granulocyte-macrophage colonies, and stayed active when given by mouth.
Biological properties and clinical uses
Summarises evidence that oral thymomodulin is active in mice and humans, induces T-cell maturation, enhances mature T-cell function with knock-on effects on B cells and macrophages, and was not mutagenic. It reports clinical trials in infections, allergies, malignancies and immune decline with ageing.
Dosing Data
Thymomodulin is not approved in the US or the EU. These are amounts given in published human studies, as stated in their abstracts; all are from small trials of the 1980s and 1990s.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no label and no published test that says what forms or vial sizes Thymomodulin is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
No worked example: none of the doses on this page is a fixed amount in mg or mcg injected under the skin or into a muscle (the routes given are: oral). There is no home-mixing step to show. The reconstitution calculator does the arithmetic for any vial.
Source: the route and amount of each dose row in Dosing Data below.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Thymomodulin, before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Thymomodulin stays intact once mixed.
How it is taken
As it was given in human studies: Oral (Daily; Study: elderly people, neutrophil function).
For injection technique, sites and needle disposal, see the mixing guide.
Source: Used in human trials: the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: not established by a measurement cited on this entry.
How long the doses were given: Study: elderly people, neutrophil function: 6 weeks; Study: children with food allergy on an elimination diet (double-blind): 90 days; Study: atopic asthma, airway responsiveness (placebo-controlled): 90 days.
When effects appear: unknown; no source on this page gives a time to effect for Thymomodulin. Results reported in the studies are under Published Research.
Source: Used in human trials, the duration of each row in Dosing Data below.
Side effects, and when to stop or get help
From the Side Effects section: No side effects recorded in 11 adults with chronic bronchitis over six months (PMID 2553636) or in 41 children with asthma (PMID 6544421); No serious adverse effects reported in the heart muscle disease trial (1995 report, listed under References); Negative in standard mutagenicity tests (PMID 3326604); No systematic safety data: the trials were small and short. Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Thymomodulin. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the trials above, which reported little on safety”).
Interactions
Unknown: a PubMed search for human interaction studies of Thymomodulin (reviewed 2026-10-28) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Thymomodulin products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Not FDA Approved (Not FDA- or EMA-approved: Drugs@FDA and the EMA medicines list hold no record (searched October 28, 2026)). Sport: Prohibited (S0 catch-all).
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
From the trials above, which reported little on safety.
Contraindications & Cautions
No current US or EU label exists. These cautions follow from the evidence and the product's origin.
Legal Status
Thymomodulin was sold in Italy as Leucotrofina in the 1980s; it is not approved in the US or the EU today.
Frequently Asked Questions
?What is thymomodulin?
A mixture of small peptides made by partly breaking down calf thymus with acid. It was developed in Italy as an immune modulator taken by mouth.
?Does it work when swallowed?
In people over 70, a single oral dose produced thymic-hormone-like activity in the blood within hours, which suggests something active is absorbed. The test measured an effect, not the peptides themselves.
?What was it tested for?
Mostly recurrent respiratory infections, food allergy, rhinitis and asthma, with smaller studies in chronic bronchitis, hepatitis B, early HIV, heart muscle disease, athletes and the elderly.
?How strong is the evidence?
Weak by modern standards. The trials were small, several had no placebo group, and none was confirmed by a large modern trial or registered on ClinicalTrials.gov.
?Is thymomodulin the same as thymalin or thymosin alpha 1?
No. Thymalin is a different thymus extract, and thymosin alpha 1 is a single defined 28-amino-acid peptide; thymomodulin is an undefined calf-thymus lysate.
?Is it the same as TFX?
No. TFX is a separate calf-thymus extract made in Poland; some papers call it 'TFX-thymomodulin', but it is a different product and its studies are not counted here.
References
- [clinical-trial] Calsini P, et al. "The pharmacodynamics of thymomodulin in elderly humans." Drugs Exp Clin Res, 1985;11(9):671-4. PMID: 3880053.
- [clinical-trial] Braga PC, et al. "Restoration of polymorphonuclear leukocyte function in elderly subjects by thymomodulin." J Chemother, 1994;6(5):354-9. PMID: 7861201.
- [clinical-trial] Fiocchi A, et al. "A double-blind clinical trial for the evaluation of the therapeutical effectiveness of a calf thymus derivative (Thymomodulin) in children with recurrent respiratory infections." Thymus, 1986;8(6):331-9. PMID: 3544353.
- [clinical-trial] Longo F, et al. "[Evaluation of the effectiveness of thymomodulin in children with recurrent respiratory infections]." Pediatr Med Chir, 1988;10(6):603-7. PMID: 3244540.
- [clinical-trial] Galli L, et al. "[Preventive effect of thymomodulin in recurrent respiratory infections in children]." Pediatr Med Chir, 1990;12(3):229-32. PMID: 2274431.
- [clinical-trial] Vettori G, et al. "[Prevention of recurrent respiratory infections in adults]." Minerva Med, 1987;78(17):1281-9. PMID: 3670682.
- [clinical-trial] Maiorano V, et al. "Thymomodulin increases the depressed production of superoxide anion by alveolar macrophages in patients with chronic bronchitis." Int J Tissue React, 1989;11(1):21-5. PMID: 2553636.
- [clinical-trial] Cavagni G, et al. ""Food allergy in children: an attempt to improve the effects of the elimination diet with an immunomodulating agent (thymomodulin). A double-blind clinical trial"." Immunopharmacol Immunotoxicol, 1989;11(1):131-42. PMID: 2668397.
- [clinical-trial] Genova R, et al. "Thymomodulin in management of food allergy in children." Int J Tissue React, 1986;8(3):239-42. PMID: 3781763.
- [clinical-trial] Pecora R, et al. "[Circadian variability of IgE in children: effects of a thymic hormone (thymomodulin)]." Pediatr Med Chir, 1991;13(3):277-8. PMID: 1945995.
- [clinical-trial] Marzari R, et al. "[Perennial allergic rhinitis. Prophylaxis of acute episodes using thymomodulin]." Minerva Med, 1987;78(22):1675-81. PMID: 3696446.
- [clinical-trial] Bagnato A, et al. "Long-term treatment with thymomodulin reduces airway hyperresponsiveness to methacholine." Ann Allergy, 1989;62(5):425-8. PMID: 2566293.
- [clinical-trial] Genova R, et al. "[A thymus extract (thymomodulin) in the prevention of childhood asthma]." Pediatr Med Chir, 1983;5(5):395-402. PMID: 6544421.
- [clinical-trial] Galli M, et al. "Attempt to treat acute type B hepatitis with an orally administered thymic extract (thymomodulin): preliminary results." Drugs Exp Clin Res, 1985;11(9):665-9. PMID: 3916838.
- [clinical-trial] Valesini G, et al. "A calf thymus acid lysate improves clinical symptoms and T-cell defects in the early stages of HIV infection: second report." Eur J Cancer Clin Oncol, 1987;23(12):1915-9. PMID: 3501759.
- [clinical-trial] Mirić M, et al. "Long-term follow up of patients with dilated heart muscle disease treated with human leucocytic interferon alpha or thymic hormones initial results." Heart, 1996;75(6):596-601. PMID: 8697164.
- [clinical-trial] Mirić M, et al. "Interferon and thymic hormones in the therapy of human myocarditis and idiopathic dilated cardiomyopathy." Eur Heart J, 1995;16 Suppl O:150-2. PMID: 8682086.
- [clinical-trial] Mirić M, et al. "Long-term follow-up of patients with myocarditis and idiopathic dilated cardiomyopathy after immunomodulatory therapy." FEMS Immunol Med Microbiol, 1994;10(1):65-74. PMID: 7874080.
- [clinical-trial] Garagiola U, et al. "Immunological patterns during regular intensive training in athletes: quantification and evaluation of a preventive pharmacological approach." J Int Med Res, 1995;23(2):85-95. PMID: 7601298.
- [pubmed] Braga PC, et al. "Thymomodulin stimulates phagocytosis in vitro by rat macrophages and human polymorphonuclear cells." J Chemother, 1993;5(5):313-6. PMID: 8106905.
- [pubmed] Balbi B, et al. "Thymomodulin increases release of granulocyte-macrophage colony stimulating factor and of tumour necrosis factor in vitro." Eur Respir J, 1992;5(9):1097-103. PMID: 1426220.
- [pubmed] Balbi B, et al. "Thymomodulin increases HLA-DR expression by macrophages but not T-lymphocyte proliferation in autologous mixed leucocyte reaction." Eur Respir J, 1993;6(1):102-9. PMID: 8425578.
- [pubmed] Poli G, et al. "Stimulation of the antibody response after treatment with thymomodulin in mice immunodepressed with cyclophosphamide and in aging mice." Int J Tissue React, 1986;8(3):231-8. PMID: 3781762.
- [pubmed] Cantelli-Forti G, et al. "Mutagenicity studies on thymomodulin." Arzneimittelforschung, 1987;37(11):1269-73. PMID: 3326604.
- [review] Cazzola P, et al. "Update and future perspectives of a thymic biological response modifier (Thymomodulin)." Immunopharmacol Immunotoxicol, 1987;9(2-3):195-216. PMID: 3325544.
- [review] Kouttab NM, et al. "Thymomodulin: biological properties and clinical applications." Med Oncol Tumor Pharmacother, 1989;6(1):5-9. PMID: 2657249.
Sources & Citations
Every study on this page was read from its PubMed record on October 29, 2026; a PubMed search for thymomodulin in titles and abstracts returned 54 records. Regulatory status comes from Drugs@FDA (openFDA), the EMA medicines list and ClinicalTrials.gov, read October 28, 2026. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.