Scientific context only. Not medical advice, not a recommendation to use.
At a glance
Complex of low-molecular polypeptides extracted from calf thymus. Approved in Russia since the 1970s as an immunomodulator. The exact composition is not standardised like a synthetic single peptide; Western controlled studies are largely absent.
Researched for
Immunomodulation in Russian clinical use (infections, oncology adjuvant)Geriatric indications in Russian studiesAnti-aging claims (largely without evidence base)
Official status
US: Unapproved
No FDA approval. Sale as a 'research chemical' is not legally covered.
Thymalin is a complex of multiple polypeptides extracted from bovine or calf thymus. Postulated mechanisms include modulation of T-lymphocyte maturation, influence on interleukin profiles and stimulation of cellular immune response. Being a multi-component preparation, individual mechanisms are difficult to disentangle. Khavinson and colleagues from St Petersburg have described the mechanism over decades in Russian publications.
02
Evidence at a glance
Reading note. The distribution shows on which evidence tier each observation sits. Strong colours mark stronger evidence — weaker tiers are deliberately visible, not hidden.
3 observations · single evidence tier
Human trial
3
03
What the studies show
Human trial
Mensch
Khavinson VKh. et al. 2002
Changes in T-cell subpopulations (CD4/CD8) and IL-2 response reported in Russian clinical studies of immunocompromised patients
What does NOT follow: Studies mostly Russian, small samples, methodological standards do not meet Western review criteria. Independent replication absent.
Human trial
Mensch
Adjuvant effect in chronic infections (tuberculosis, chronic hepatitis) documented in Russian open-label studies
What does NOT follow: Open-label trials without blinding or placebo control in populations with limited access to standard therapy. Effect sizes and endpoint definitions not ICH-compliant.
Human trial
Mensch (Geriatrie)
Geriatric endpoints (lifespan, biological markers) investigated in open-label long-term studies by the Khavinson group
What does NOT follow: Very long observation periods in exclusively Russian cohorts. Western methodological critique addresses confounder control, selection and endpoint definition.
04
Where studies disagree
Open question
Are the immunomodulatory effects of Thymalin reproducible outside the Russian research ecosystem?
POSITION A
The Khavinson group has consistently published positive findings for decades.
POSITION B
There is virtually no independent Western replication research. Western reviews of thymus polypeptides are methodologically cautious.
CURRENT STATE · As with epitalon, the absence of independent replication is the central weakness of the evidence base.
05
Pharmacokinetics
Theoretical concentration curve at a half-life of 0.5 h. Pure pharmacokinetic model — not a dosing recommendation.
Which routes of administration the available studies describe — neutral reporting, not a usage guide.
Intramuscular
In Russian registration studies administered predominantly as IM injection in cycles.
07
Known adverse events from studies
Factual reporting of what studies observed. Not a safety statement for individual use.
Human trial
Low profile of documented adverse events
Western pharmacovigilance is absent. Being a biological multi-component preparation, batch-to-batch variability can influence adverse-event profiles.
in russischen Daten überwiegend mild
07b
Interactions & combinations
Documented interactions and contraindications from studies, prescribing information and guidelines. Where no data exists, this is stated.
Reporting of risks, NOT a combination guide. The absence of an entry does not mean „safe to combine“ but „not sufficiently studied“.
No documented interactions recorded
We have not yet found robustly documented interactions for this peptide. This does NOT mean none exist — the data is limited.
08
Risks & hygiene aspects in the literature
What regulatory and scientific literature reports on risks, sterility and identity in non-pharmaceutical sources — descriptive, not a hygiene guide.
Multi-component preparation without standardisation
Unlike a synthetic single peptide, batch composition is not defined by international pharmacopoeial standards. Active identity per batch depends on the extraction process.
10
Anecdotal observations
Weakest evidence tier — not supported by studies
Reading note. This section gathers popular claims from communities and forums. They are explicitly marked as weakest-tier evidence. Unblinded self-reports are particularly prone to placebo, recall and confirmation biases.
Why no amounts or protocols are listed here. We deliberately show only WHAT communities report — not in what amount or how it is used. Anecdotal "doses" or "biohacker protocols" are neither verified nor standardised nor safe; publishing them would be a usage guide, which we do not provide on principle. Specific amounts belong in a conversation with a doctor, not in a forum.
In anti-aging communities Thymalin is marketed as an 'immune booster' and 'bio-regulator'.
common in English-language longevity forums
Not supported by studies: These claims rest predominantly on Russian literature from a single research tradition (Khavinson) without independent Western replication. Marketing claims often extend well beyond the published evidence.
11
Legal status by country
Country
Status
Note
Checked
RU
Prescription
Approved as a medicine in Russia and some CIS states (manufacturers include Samson-Med, St Petersburg). Prescription-only.
2026-05-22
United States
Unapproved
No FDA approval. Sale as a 'research chemical' is not legally covered.
2026-05-22
Germany
Unapproved
No EMA or BfArM approval. Not marketable as a medicine.
2026-05-22
12
Reconstitution calculator
Pure mg/mL maths — works like a calculator. Not a usage recommendation.
Peptides ship as a dry powder. Once dissolved in a liquid (reconstitution), this calculator answers a single question: how much substance is in one millilitre of solution afterwards?
1Enter the vial's substance amount (printed on the label).
2Enter how much solvent you add.
3Result = concentration in mg per mL.
Printed on the label
/
Liquid you add
=
2.50
mg / mL
5 mg in 2 mL gives 2.50 mg/mL — each millilitre contains 2.50 mg of substance.