Peptide Comparison
Epitalon vs Thymalin
Editorial breakdown of mechanism, evidence, decision criteria, and the misconceptions worth calling out.
Depends on goal
Both come from the same Russian research program and neither has been replicated independently in the West, so the choice between them turns on which organ system the question concerns rather than which has better evidence. Epitalon is a defined synthetic tetrapeptide aimed at pineal and telomerase endpoints. Thymalin is a thymic extract aimed at T-cell function. For anyone examining supply, the practical difference is that a four-amino-acid sequence can be confirmed by mass spectrometry and a tissue extract cannot be characterized the same way. Consult a qualified clinician before any human use.
Evidence at a glance
FDA-approved Phase 3 Phase 2 / approved abroad Anecdotal + animal Preclinical / flagged
The actual difference
Epitalon is Ala-Glu-Asp-Gly, a synthetic tetrapeptide, given subcutaneously in 10 to 20 day courses with a plasma half-life around 20 minutes. Thymalin is a peptide fraction extracted from calf thymus, given intramuscularly in 5 to 10 day courses, with a half-life the catalog records as variable. Both trace to Khavinson's group in St Petersburg, and the supporting literature is clinical and observational rather than randomized and blinded.
Which one to pick
Pick Epitalon if
- The endpoint concerns circadian rhythm, melatonin regulation or telomerase biology
- Analytical confirmation of identity matters, which a defined sequence permits and an extract does not
- Subcutaneous administration is the constraint
Pick Thymalin if
- The endpoint concerns T-cell function or immune aging
- The reference question is about the Khavinson immune cohorts specifically
- Intramuscular administration is available
Avoid both if
- Independent Western replication is a requirement, because neither compound has it
- An autoimmune condition is present, since Thymalin is described as an immune modulator and the direction of that effect in autoimmunity has not been established
- Pregnancy or planning pregnancy
Common confusions
- 'Epitalon lengthens telomeres in humans'. Not established. The telomerase claims rest on cell and animal work plus Russian clinical reports, and no independent trial has measured telomere length in people taking it.
- 'Thymalin and thymosin alpha-1 are the same thing'. They are not. Thymosin alpha-1 is a defined 28-amino-acid peptide approved in around 30 countries. Thymalin is an undefined extract fraction. Only one of the two has a characterized active molecule.
- 'Russian clinical data is not real data'. Wrong in the other direction. The Khavinson cohorts carry follow-up periods that Western trials rarely fund. The limitation is independent replication and blinding, not the country of origin.
Side-by-side
| Epitalon | Thymalin | |
|---|---|---|
| Class | Khavinson pineal tetrapeptide; longevity peptide | Thymic peptide extract; immunomodulator |
| Drug class | Longevity | Immune |
| Mechanism | Activates telomerase gene expression; modulates pineal function and melatonin secretion | Restores T-cell function; immune regulation in aged patients |
| Route | SC / Oral | IM |
| Half-life | ~20 min | Variable |
| Dosage (research) | 5 mg SC daily for 10-20 day cycles 2x yearly (Khavinson Russian gerontology starting dose, range up to 10 mg/day per published protocols) | 10 mg IM daily for 5-10 day courses |
| Evidence tier | Russia-Clinical + Animal Studies | Russian Clinical + Observational |
| Research depth | 176 indexed | 192 indexed |
| Availability | Research | Research |
| Reported risks | Limited Western trials; Russian-origin data | Limited Western evidence |
Reported research data only. "Studied for" and "reported in literature" describe published research focus, not clinical recommendation. Most peptides catalogued here are not FDA-approved for human use.
Frequently asked questions
Should I pick Epitalon or Thymalin?
Both come from the same Russian research program and neither has been replicated independently in the West, so the choice between them turns on which organ system the question concerns rather than which has better evidence. Epitalon is a defined synthetic tetrapeptide aimed at pineal and telomerase endpoints. Thymalin is a thymic extract aimed at T-cell function. For anyone examining supply, the practical difference is that a four-amino-acid sequence can be confirmed by mass spectrometry and a tissue extract cannot be characterized the same way. Consult a qualified clinician before any human use.
What is the difference between Epitalon and Thymalin?
Epitalon is classed as Khavinson pineal tetrapeptide; longevity peptide; Thymalin is classed as Thymic peptide extract; immunomodulator. Reported mechanism: Epitalon, Activates telomerase gene expression; modulates pineal function and melatonin secretion; Thymalin, Restores T-cell function; immune regulation in aged patients. Reported half-life: Epitalon, ~20 min; Thymalin, Variable. Routes in published studies: Epitalon, SC / Oral; Thymalin, IM.
Which has stronger evidence, Epitalon or Thymalin?
Epitalon has the stronger evidence base on PeptideHelper.org's five-step evidence scale, which runs from preclinical to FDA-approved. Epitalon is graded Russia-Clinical + Animal Studies, with 7 cited sources on its reference page and 176 indexed studies. Thymalin is graded Russian Clinical + Observational, with 2 cited sources on its reference page and 192 indexed studies.
Which is more accessible, Epitalon or Thymalin?
Neither Epitalon nor Thymalin is an FDA-approved drug. Catalog status: Epitalon, Research; Thymalin, Research. Epitalon's nomination for FDA's bulk-substance lists was flagged by FDA and then withdrawn.
Are Epitalon and Thymalin ever combined?
Epitalon and Thymalin appear together in no stack catalogued on PeptideHelper.org, and the interaction engine raises no flag for the pair.
Open the PeptideHelper.org compare tool to add more compounds to this side-by-side and filter by evidence tier interactively.
Loading interactive view…