Thymalin
Thymic Factor / Thymalin dipeptide
A peptide extract of calf thymus developed in Russia as a thymic bioregulator. It is a registered medicine in Russia, where it has been used for decades for immune support in aging, after surgery and in immunodeficiency; Russian studies report effects on T-cell counts and function. It is not FDA-approved.
Half-life
~30 minutes (rapid tissue distribution; immunomodulatory effects last days)
Typical Dose
5–10 mg/day IM for 5–10 days
6/10Route
intramuscular
Category
immune
Evidence Overview
Strength of evidence across clinical, expert, and experimental lanes.
How Thymalin is dosed in practice
Usually taken by intramuscular injection. Typical range: 5–10 mg/day IM for 5–10 days. Half-life: ~30 minutes (rapid tissue distribution; immunomodulatory effects last days). Each card gives the dose, frequency and duration from one evidence lane: Clinical (human trials), Expert (practitioner protocols) or Experimental (early or animal data). These ranges describe what has been studied or used; they are not a prescription.
Work out the units to draw with the reconstitution calculator, how long a vial lasts with the vial duration calculator, and how levels fall between doses with the half-life calculator.
A prescription immune-support medicine registered in Russia for immunodeficiency states. A 2003 Russian study in 266 older adults reported lower mortality over 6–8 years after thymalin and/or epithalamin courses; other Russian studies used it as add-on therapy (tuberculosis, lung abscess, COVID-19) and their abstracts do not give doses.
- Russian product label
- Long-term study in older adults (2003)
- Russian add-on studies (2012, 2021, 2022)
Anti-aging practitioners use Thymalin courses to restore declining thymic function in patients over 40. Combined with Epithalon for comprehensive immune and endocrine rejuvenation. Popular in European longevity clinics.
- European longevity clinic protocols
- Khavinson bioregulator therapy practitioners
- Anti-aging medicine conference presentations
Users report improved resilience to infections and faster recovery from illness after Thymalin courses. Combined with Epithalon by the biohacking community for 'thymic reset' protocols. Sourcing outside Russia can be challenging.
- Longevity biohacking forums — Khavinson peptide experience reports
- Reddit r/Peptides — Thymalin sourcing and protocol discussions
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Upgrade to ProSafety & Contraindications
- Autoimmune diseases in acute flare (may overstimulate immune response)
- Pregnancy or breastfeeding
- Known allergy to bovine-derived products
Thymalin: common questions
What is Thymalin?
A peptide extract of calf thymus developed in Russia as a thymic bioregulator. It is a registered medicine in Russia, where it has been used for decades for immune support in aging, after surgery and in immunodeficiency; Russian studies report effects on T-cell counts and function. It is not FDA-approved.
How is Thymalin dosed?
Thymalin is usually taken by intramuscular injection. Typical range in DoseCraft's library: 5–10 mg/day IM for 5–10 days. Clinical (human trials): 5–20 mg/day IM in adults (30–100 mg per course), per the Russian label; Once daily; 3–10 days; course repeated after 1–6 months if needed. Expert (practitioner protocols): 10 mg/day IM for 10 days; Once daily during treatment course; 10-day courses, 1–2 times per year. Experimental (early or animal data): 5–10 mg/day IM; Daily for 10 days; 10-day courses, twice yearly. These ranges describe what has been studied or used; they are not a prescription.
Is Thymalin FDA-approved?
No. Thymalin is not FDA-approved. It is an approved medicine in Russia; that approval applies there only, not in the US.
What is the half-life of Thymalin?
DoseCraft's library lists a half-life of ~30 minutes (rapid tissue distribution; immunomodulatory effects last days). Half-life sets how often a compound is dosed and how long it takes to clear: about five half-lives.
Who should not use Thymalin?
Listed contraindications: Autoimmune diseases in acute flare (may overstimulate immune response); Pregnancy or breastfeeding; Known allergy to bovine-derived products.
Information is for educational purposes only. Always consult a licensed healthcare provider before starting any peptide regimen.
Page updated . How we grade evidence: methodology.