Thymus Extracts

What do they do? The thymus is one of our major immune system glands. It is composed of two soft pinkish-gray lobes lying in bib-like fashion just below the thyroid gland and above the heart. To a large extent, the health of the thymus determines the health of the immune system. The thymus is responsible for many immune system functions, including the production of T lymphocytes, a type of white blood cell responsible for “cell-mediated immunity.” Cell-mediated immunity refers to immune mechanisms not controlled or mediated by antibodies. Cell-mediated immunity is extremely important in the resistance to infection by certain bacteria, yeast (including Candida albicans), fungi, parasites, and viruses (including herpes simplex, Epstein-Barr, and the viruses that cause hepatitis). Cell-mediated immunity is also critical in protecting against the development of cancer, allergies, and autoimmune disorders such as rheumatoid arthritis. The thymus gland also releases several hormones, such as thymosin, thymopoeitin, and serum thymic factor, that regulate many immune functions.

Thymus extracts used as nutritional supplements are most often derived from young calves (bovine). The oral calf thymus extract that has been studied scientifically is specially prepared to concentrate small protein-like molecules (polypeptides). This extract (known as Thymomodulin®) has been shown effective in preventing recurrent upper respiratory tract infections.

Preliminary studies suggest that Thymomodulin may also be helpful in (1) improving one of the T-cell defects in patients with human immunodeficiency virus infection (HIV—the virus that causes AIDS); (2) treating acute and chronic hepatitis B infections; (3) restoring the number of peripheral white blood cells in cancer patients undergoing chemotherapy or radiation; and (4) relieving allergies, including asthma, hay fever, and food allergies, in children.1 2 The effectiveness of Thymomodulin in these conditions may be the result of improved thymus gland activity, or it may be due to the presence of hormones or other biologically active substances in the extract.

The ability of Thymomodulin to improve immune function and reduce the number of recurrent infections has been shown in double-blind studies of children and adults with a history of recurrent respiratory-tract infections.3 4 5 6 7 Thymomodulin has also been shown in a double-blind study to improve immune function in cases of exercise-induced immune suppression. In addition, preliminary studies have shown the extract to improve immune function in people with diabetes and in elderly people.8 9 10 11 (Extreme exercise, diabetes, and aging are all associated with suppression of immune function.)

Preliminary studies in patients with acute or chronic hepatitis suggest that supplementation with Thymomodulin may be helpful.12 13 However, additional studies are needed to confirm these findings.

In a preliminary study in patients with early HIV infection, Thymomodulin improved several measures of immune function, including an increase in the number of T-helper cells, one of the goals in the treatment of HIV infection.14 Thymomodulin (given orally or by injection) has been used in cancer patients to counteract the decline in white-blood-cell levels that can result from chemotherapy or radiation.15 16 17 18 19 20 In test tube studies, Thymomodulin and other thymus extracts have been shown to exert a number of effects on white blood cells (e.g., increasing both the bone marrow production and functional activity of white blood cells).21 22 However, it is not yet known if this effect can be achieved with the use of oral thymus extracts.

The oral administration of Thymomodulin has been shown in preliminary and double-blind clinical trials to improve the symptoms and course of hay fever, allergic rhinitis, asthma, eczema, and food allergies (in conjunction with an allergy elimination diet).23 24 25 26 27 28 29 30 Presumably, this clinical improvement results from restoring proper control over immune function.

Thymomodulin given by injection has also been shown to be helpful in the treatment of diseases of the heart muscle (i.e., idiopathic myocarditis and idiopathic dilated cardiomyopathy).31 32 It is not known whether oral thymus extracts can achieve these same benefits.

Where are they found? Thymus extracts (from bovine sources) are found in capsules and tablets as a dietary supplement. Thymomodulin is not available in the United States, and it is unknown whether any of the thymus extracts that are available have the same effects as Thymomodulin.

Thymus extracthave been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating Health Concerns
3Stars Bronchitis
2Stars Allergies
Hay fever
Hepatitis
Immune function
Recurrent upper respiratory tract infections
1Star Asthma
HIV infection
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

Who is likely to be deficient? Since it is not an essential nutrient, no deficiency state exists.

How much is usually taken? A number of different thymus preparations are commercially available. However, whether any of them have the same effects as Thymomodulin, which is not available in the United States, is still unknown. The recommended amount of thymus extract varies according to the type of preparation.

Are there any side effects or interactions? No side effects, adverse reactions, or drug interactions have been reported with the use of thymus preparations.

Are there any drug interactions? Certain medications may interact with thymus extracts. Refer to the drug interactions safety check for a list of those medications.

References:

1. Cazzola P, Mazzanti P, Bossi G. In vivo modulating effect of a calf thymus acid lysate on human T lymphocyte subsets and CD4+/CD8+ ratio in the course of different diseases. Curr Ther Res 1987;42:1011–7.

2. Kouttab NM, Prada M, Cazzola P. Thymomodulin: Biological properties and clinical applications. Med Oncol Tumor Pharmacother 1989;6:5–9 [review].

3. Fiocchi A, Borella E, Riva E, et al. A double-blind clinical trial for the evaluation of the therapeutic effectiveness of a calf thymus derivative (Thymomodulin) in children with recurrent respiratory infections. Thymus 1986;8:831–9.

4. Galli L, de Martino M, Azzari C, et al. Preventive effect of thymomodulin in recurrent respiratory infections in children. Pediatr Med Chir 1990;12:229–32.

5. Vettori G, Lazzaro A, Mazzanti P, Cazzola P. Prevention of recurrent respiratory infections in adults. Minerva Med 1987;78:1281–9.

6. Longo F, Lepore L, Agosti E, Panizon F. Evaluation of the effectiveness of thymomodulin in children with recurrent respiratory infections. Pediatr Med Chir 1988;10:603–7.

7. Maiorano V, Chianese R, Fumarulo R, et al. Thymomodulin increases the depressed production of superoxide anion by alveolar macrophages in patients with chronic bronchitis. Int J Tissue React 1989;11:21–5.

8. Garagiola U, Buzzetti M, Cardella E. Immunological patterns during regular intensive training in athletes: quantification and evaluation of a preventive pharmacological approach. J Int Med Res 1995;23:85–95.

9. Wysocki J, Wierusz-Wysocka B, Wykretowicz A, Wysocki H. The influence of thymus extracts on the chemotaxis of polymorphonuclear neutrophils (PMN) from patients with insulin-dependent diabetes mellitus (IDD). Thymus 1992;20:63–7.

10. Calsini P, Mocchegiani E, Fabris N. The pharmacodynamics of thymomodulin in elderly humans. Drugs Exp Clin Res 1985;11:671–4.

11. Braga PC, Dal Sasso M, Maci S, et al. Restoration of polymorphonuclear leukocyte function in elderly subjects by thymomodulin. J Chemother 1994;6:354–9.

12. Galli M, Crocchiolo P, Negri C, et al. Attempt to treat acute type B hepatitis with an orally administered thymic extract (Thymomodulin): preliminary results. Drugs Expt Clin Res 1985;11:665–9.

13. Bortolotti F, Cadrobbi P, Criverllaro C, et al. Effect of an orally administered thymic derivative, Thymodulin, in chronic type B hepatitis in children. Curr Ther Res 1988;43:67–72.

14. Valesini G, Barnaba V, Benvenuto R, et al. A calf thymus lysate improves clinical symptoms and T-cell defects in the early stages of HIV infection: second report. Eur J Cancer Clin Oncol 1987;23:1915–9.

15. Kouttab NM, Prada M, Cazzola P. Thymomodulin: biological properties and clinical applications. Med Oncol Tumor Pharmacother 1989;6:5–9 [review].

16. Kang SD, Lee BH, Yang JH, Lee CY. The effects of calf-thymus extract on recovery of bone marrow function in anticancer chemotherapy. New Med J 1985;28:11–5.

17. Schulof RS. Thymic peptide hormones: basic properties and clinical applications in cancer. Crit Rev in Oncol Hematol 1985;3:309–76 [review].

18. Meneses G, Delgado MA, Perez-Machado A, et al. Thymostimulin increases natural cytotoxic activity in patients with breast cancer. Int J Immunopharmacol 1997;19:187–93.

19. Skotnicki AB. Thymic hormones and lymphokines. Drug Today 1989;25:337–62 [review].

20. Ernst E. Thymus therapy for cancer? A criteria-based, systematic review. Eur J Cancer 1997;33:531–5 [review].

21. Vasilopoulos G, Porwit A, Lauren L, et al. The effect of a calf thymus acid lysate on bone marrow cell growth in vitro. Immunopharmacol Immunotoxicol 1988;10:523–36.

22. Skotnicki AB. Thymic hormones and lymphokines. Drug Today 1989;25:337–62 [review].

23. Cazzola P, Mazzanti P, Bossi G. In vivo modulating effect of a calf thymus acid lysate on human T lymphocyte subsets and CD4+/CD8+ ratio in the course of different diseases. Curr Ther Res 1987;42:1011–7.

24. Kouttab NM, Prada M, Cazzola P. Thymomodulin: biological properties and clinical applications. Med Oncol Tumor Pharmacother 1989;6:5–9 [review].

25. Marzari R, Mazzanti P, Cazzola P, Pirodda E. Perennial allergic rhinitis: prevention of the acute episodes with Thymomodulin. Minerva Med 1987;78:1675–81.

26. Genova R, Guerra A. A thymus extract (thymomodulin) in the prevention of childhood asthma. Pediatr Med Chir 1983;5:395–402.

27. Bagnato A, Brovedani P, Comina P, et al. Long-term treatment with thymomodulin reduces airway hyperresponsiveness to methacholine. Ann Allergy 1989;62:425–8.

28. Fiocchi A, Grasso U, Travaglini P, et al. A double blind clinical trials on the effectiveness of a thymic derivative (Thymomodulin) in the treatment of children with atopic dermatitis. Int J Immunother 1987;3:279–84.

29. Cavagni G, Piscopo E, Rigoli E, 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;11:131–42.

30. Genova R, Guerra A. Thymomodulin in management of food allergy in children. Int J Tissue React 1986;8:239–42.

31. Miric M, Vasiljevic J, Bojic 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;75:596–601.

32. Miric M, Miskovic A, Brkic S, et al. Long-term follow-up of patients with myocarditis and idiopathic dilated cardiomyopathy after immunomodulatory therapy. Immunol Med Microbiol 1994;10:65–74.