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Comparison

Thymalin vs Thymogen

Thymalin is thymic & immune; Thymogen is bioregulators. They are compared here because they are frequently considered against each other, not because they act alike.

Thymalin Thymogen
Class Thymic & immune Bioregulators
Evidence Preliminary human Preliminary human
Human trials ~5 ~2
Half-life Not established Not established
Reported range 10-20 mg 100-200 mcg
Frequency Once daily for 5-10 days Once daily for 10-20 day courses, 2-3 courses per year
Routes Intramuscular, Subcutaneous Subcutaneous, Oral, Intramuscular
FDA approved No No
Research use only Yes Yes
Banned in sport No No
Studied for Immune restoration research, Geriatric immunity research Immune function research, Infection recovery research
Reported side effects Injection-site reactions, Transient fatigue Injection-site reactions, Transient fatigue

Thymalin

Thymalin is a mixture of polypeptide fractions isolated from bovine thymus rather than a single defined molecule, which is an important distinction from thymosin alpha-1. It is reported to restore T-lymphocyte differentiation and normalise immune indices in immunodeficiency states. The frequently cited evidence is a long-running Russian geriatric cohort reporting reduced mortality; that work has not been replicated under contemporary trial standards.

Thymogen

Thymogen is one of the short peptide bioregulators characterised by Vladimir Khavinson, a series of di- to tetrapeptides each associated with a specific tissue. The proposed mechanism is direct interaction with DNA promoter regions to modulate transcription of tissue-specific genes, restoring protein synthesis in ageing or damaged tissue. A dipeptide derived from thymalin, registered in Russia as an immunostimulant. Nearly all supporting work comes from a single research group and has not been independently replicated under contemporary trial standards, which is the central limitation of the entire class and should be stated on every page in it.

Thymalin vs Thymogen: common questions

What is the difference between Thymalin and Thymogen?

Thymalin is thymic & immune and Thymogen is bioregulators, so they act on different pathways. Thymalin: A polypeptide fraction extracted from calf thymus, used clinically in Russia and studied in long-term geriatric cohorts. Thymogen: A short peptide bioregulator directed at the thymus, from the Khavinson series developed at the St. Petersburg Institute of Bioregulation and Gerontology.

Which has stronger evidence, Thymalin or Thymogen?

They sit at the same evidence level: preliminary human. Thymalin has about 5 human studies and Thymogen about 2.

Are Thymalin and Thymogen FDA approved?

Neither is FDA approved for any indication.

References

Regulatory and primary sources

  1. PubChem compound record (CID 3085284) ↗ · structure, identifiers, synonyms
  2. FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
  3. PubChem compound record (CID 100094) ↗ · structure, identifiers, synonyms

Published literature

  1. Khavinson VKh. Peptides and Ageing.Neuro Endocrinol Lett 2002.PubMed 12374906
  2. Khavinson VKh, Morozov VG. [Geroprotective effect of thymalin and epithalamin].Adv Gerontol 2002.PubMed 12577695
  3. Litvinenko GI, Shurlygina AV, Dergacheva TI, et al.. Chrono- and Immunocorrection of Inflammatory Disorders of Internal Reproductive Organs in Women of Reproductive Age.Bull Exp Biol Med 2015.PubMed 26033592 · doi:10.1007/s10517-015-2890-0
  4. Khavinson VKh, Morozov VG. Peptides of pineal gland and thymus prolong human life.Neuro Endocrinol Lett 2003.PubMed 14523363
  5. Lin'kova NS, Poliakova VO, Kvetnoĭ IM, et al.. [Characteristics of the pineal gland and thymus relationship in aging].Adv Gerontol 2011.PubMed 21809618
  6. Lin'kova NS, Poliakova VO, Trofimov AV, et al.. [Influence of peptides from pineal gland on thymus function at aging].Adv Gerontol 2010.PubMed 21510076
  7. Musienko GV. [Thymalin in the combined treatment of parkinsonism patients].Lik Sprava 1999.PubMed 10424021
  8. Domina EA. Chornobyl catastrophe: cytogenetic effects of low dose ionizing radiation and their modification.Exp Oncol 2016.PubMed 28230819
  9. Silin DS, Lyubomska OV, Ershov FI, et al.. Synthetic and natural immunomodulators acting as interferon inducers.Curr Pharm Des 2009.PubMed 19355963 · doi:10.2174/138161209787846847
  10. Deigin V, Linkova N, Vinogradova J, et al.. The First Reciprocal Activities of Chiral Peptide Pharmaceuticals: Thymogen and Thymodepressin, as Examples.Int J Mol Sci 2024.PubMed 38732260 · doi:10.3390/ijms25095042
  11. Sokolova GB, Sinitsyn MV, Kozhemiakin LA, et al.. [Glutoxim in the complex treatment of tuberculosis].Antibiot Khimioter 2002.PubMed 12087719
  12. Balasaniants GS, Sukhanov DS. [Current aspects of pathogenetic therapy in tuberculosis].Ter Arkh 2011.PubMed 21961327
  13. Sinitsyn MV, Bogadel'nikova IV, Sokolova GB. [Thiopoeitins in the treatment of tuberculosis].Probl Tuberk Bolezn Legk 2007.PubMed 17657963
  14. Tsvelev IuV, Khavinson VKh, Diachuk AV, et al.. [Thymogen in the complex treatment of inflammatory diseases of the female genital system].Akush Ginekol (Mosk) 1992.PubMed 1476231
  15. Abdullaev IA. [Application of ozonated perftoran in the treatment of spreaded peritonitis].Klin Khir 2014.PubMed 24923143

Literature retrieved from PubMed on October 16, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.

Read this first This page compares published reference data. It is not medical advice and not a recommendation to use either compound. Several compounds documented on this site are not approved for human use.