Thymalin
Thymalin — the founding Soviet peptide bioregulator: thymus immunity, longevity claims, and the replication gap

Class: peptide
Synonyms: Thymalin
Тималин
thymic peptide bioregulator
Function tags: immune support / immunocorrection
thymic / T-cell restoration
geroprotection (anti-aging, claimed)
recovery
Overall evidence grade: C
WADA prohibited: no
Last updated: 2026-07-13

In brief: Thymalin is a calf-thymus polypeptide complex and the founding compound of the Soviet/Russian "peptide bioregulator" school — the program (Khavinson & Morozov, 1970s) that also produced Epitalon (#35) and a family of short-peptide drugs (Thymogen, Vilon, Crystagen). Because the thymus trains T-cells and shrinks with age (driving immunosenescence), Thymalin is used as a thymic immune-restorative, and has been a registered drug in Russia/Eastern Europe for ~40 years. The Russian literature reports restored lymphocyte counts, fewer respiratory infections in the elderly (2.0–2.4× reduction), and striking geroprotection — a famous 6–8-year study in 266 elderly people reported mortality reductions of ~2× with Thymalin and ~4.1× with Thymalin + Epithalamin combined. The proposed mechanism is elegant: its short peptides (KE, EW, EDP) bind DNA/histones and regulate gene expression. The decisive caveat is epistemic, not mechanistic: almost all of this evidence comes from one research group (Khavinson's), the trials are generally small and single-region, and none have been independently replicated at the scale Western regulators require. So the fair read: decades of real-world use and supportive-but-methodologically-limited data — genuinely intriguing, not independently established, and unapproved in the West.

## Identity unlike the synthetic single peptides elsewhere in this register, Thymalin is a **polypeptide complex extracted from the thymus of young calves** (by mild acid extraction) and standardized as a pharmaceutical. The thymus is the organ that "**educates**" T-lymphocytes; Thymalin is positioned as a **thymic immune-restorative / immunocorrector**. It's the **prototype of the "peptide bioregulator" concept** — the idea that short peptides act as precise regulators of gene expression in specific tissues rather than as blunt pharmacological agents. ## Mechanism (as proposed) Thymalin's activity is attributed to its **short peptides — KE (Lys-Glu), EW (Glu-Trp), EDP (Glu-Asp-Pro)** — which are proposed to **bind directly to double-stranded DNA and/or histone proteins** and thereby **regulate gene expression**: the synthesis of immune-system proteins, cytokines, heat-shock proteins, "gerontogenes," and the **differentiation/proliferation of stem and immune cells** (while reducing apoptosis). Functionally, the pitch is **restoring the aging thymus's T-cell output** and thus pushing back on immunosenescence — and, in the geroprotection framing, "normalizing" cardiovascular/endocrine/immune/nervous-system indices. This "**short peptides as epigenetic gene-expression regulators**" model is the theoretical heart of the entire bioregulator school. It is **mechanistically coherent and supported by the group's own molecular work**, but — like the clinical claims — **not broadly validated by independent labs.**

Evidence grades by outcome:
outcome: Immune restoration / immunocorrection (the registered use)
grade: C
base: Decades of Russian clinical use; reports of restored lymphocyte counts/function; 2.0–2.4× fewer acute respiratory infections in elderly
caveat: Real clinical tradition + some RCT/placebo work — but single-group, small, single-region, not independently replicated; unapproved in West
outcome: Geroprotection / longevity
grade: C
base: 266-person, 6–8-yr study: mortality ~2× lower (Thymalin), ~4.1× lower (Thymalin + Epithalamin); animal lifespan/tumor-reduction data
caveat: Extraordinary claims, extraordinary caveats: same group, older methodology, no independent replication; can't be taken at Western-regulatory face value
outcome: Severe COVID-19 immune modulation (elderly)
grade: D
base: 2021 study: regulation of immune status, anti-"cytokine-storm" rationale
caveat: Small/recent, single-group; hypothesis-generating
outcome: Radiation / hematopoietic immune injury
grade: D
base: Older Khavinson-group work
caveat: Limited, dated, unreplicated
outcome: Independent replication / overall quality
base: ~50 years of program output
caveat: The core issue: overwhelmingly one lineage of investigators; western-standard independent confirmation absent
outcome: Safety
base: Long clinical use
caveat: Generally described as well-tolerated; bovine-derived (allergy/immunogenicity); contraindicated in active autoimmune disease, lymphoma/leukemia, immunosuppression

Legal status:
region: US
status: Not approved
note: not approved; the FDA has not reviewed it for any indication; not available as an approved drug in the West. Obtainable only as a research compound.

Cosmetic claims:

Note: The founding peptide of the Soviet "peptide bioregulator" school — decades of use, striking claims, thin independent evidence. This entry anchors a distinct research tradition and pairs directly with Epitalon (#35). Three points: (1) it's not a single peptide but a calf-thymus polypeptide complex, a registered immune drug in Russia/Eastern Europe for ~40 years; (2) it's the first-ever "peptide bioregulator" — the compound that launched Vladimir Khavinson's entire program (Epitalon, Thymogen, Vilon, Cortexin all descend from this method); (3) its human data include remarkable geroprotection claims (mortality reductions of 2–4×) — but almost all from one research group, small and not independently replicated to Western standards.
Status note: status: long Russian clinical use, unapproved in West; the decisive future signal would be independent, non-affiliated replication of the immune/geroprotective claims

Sources:
Morozov VG, Khavinson VKh — original Thymalin development (1981-1982); Natural and synthetic thymic peptides as therapeutics for immune dysfunction (Int J Immunopharmacol, 1998).
Khavinson VKh, Morozov VG. Geroprotective effect of thymalin and epithalamin. Adv Gerontol / Usp Gerontol. 2002 (PMID 12577695); Peptides of pineal gland and thymus prolong human life. Neuroendocrinol Lett. 2003 (266 elderly, 6–8 yr; the 2×/4.1× mortality data).
The Use of Thymalin for Immunocorrection and Molecular Aspects of Biological Activity (Biol Bull Rev, 2021) — KE/EW/EDP short peptides, gene-expression mechanism.
Peptide Drug Thymalin Regulates Immune Status in Severe COVID-19 Older Patients (2021).
Independent-appraisal note: the evidence base is decades deep but overwhelmingly from Khavinson-affiliated groups; independent, Western-standard replication is lacking, and it is not FDA/EMA-approved.