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Prescription medication — not a dietary supplement
Thymalinis a prescription (or investigational) drug, not a supplement. It is included here for reference because people research and discuss it (often used off-label) — not as a recommendation. Take it only under a qualified clinician's supervision and only as prescribed; do not source it from grey-market vendors, where identity, purity, and dosing are unverified. The evidence below reflects its clinical trials.
What the evidence says
Most Thymalin studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality studies published 2003–2023.
Based on 6 studies
Confidence
LowBy outcome
The current evidence for Thymalin is insufficient to assign an evidence score, based on 6 indexed studies. A polypeptide complex extracted from the thymus, registered as an immunomodulator medicine in Russia and several CIS countries — so unlike grey-market peptides it has real (if mostly Russian-language and low-quality) human studies. Thymalin is promoted to 'normalize' immune function by stimulating T-lymphocyte differentiation, with claimed uses in respiratory infections, COVID-19 adjuvant therapy, and even longevity. The headline evidence is striking but weak: an open-label Russian cohort reported a 2-fold drop in mortality in elderly people treated with thymalin (± a pineal peptide) over 6-8 years, and unblinded COVID-19 series reported lower hospital mortality when added to standard care. Almost none of this is double-blind, placebo-controlled, or replicated outside Russia/CIS; sample sizes are small; mechanism work is largely in-vitro. Western regulators have NOT approved it. Treat the longevity and mortality claims with strong skepticism. Representative study: PMID 36169363.
PT-141
Mostly mechanism / observationalA melanocortin-receptor (MC4R) agonist peptide for low sexual desire. Important honest framing: unlike most 'research peptides', bremelanotide is an FDA-APPROVED prescription drug — Vyleesi, approved 2019 — for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, self-injected subcutaneously on-demand. It has real phase-3 RCTs (the RECONNECT program). The catch: the approved-trial benefit was statistically significant but small (a fraction of a point on desire scales), nausea is very common, and it transiently raises blood pressure. Grey-market 'PT-141' vials sold online are NOT the approved drug and are unregulated.
Last reviewed June 2026 · evidence from 6 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Thymalin (thymus peptide bioregulator)
A polypeptide complex extracted from the thymus, registered as an immunomodulator medicine in Russia and several CIS countries — so unlike grey-market peptides it has real (if mostly Russian-language and low-quality) human studies. Thymalin is promoted to 'normalize' immune function by stimulating T-lymphocyte differentiation, with claimed uses in respiratory infections, COVID-19 adjuvant therapy, and even longevity. The headline evidence is striking but weak: an open-label Russian cohort reported a 2-fold drop in mortality in elderly people treated with thymalin (± a pineal peptide) over 6-8 years, and unblinded COVID-19 series reported lower hospital mortality when added to standard care. Almost none of this is double-blind, placebo-controlled, or replicated outside Russia/CIS; sample sizes are small; mechanism work is largely in-vitro. Western regulators have NOT approved it. Treat the longevity and mortality claims with strong skepticism.
A registered Russian/CIS immunomodulator with a plausible mechanism and some human reports, but its evidence is small, unblinded, single-center and unreplicated, so it scores Emerging.
Thymalin is a polypeptide complex isolated from animal thymus tissue, developed by the St. Petersburg Institute of Bioregulation and Gerontology (the Khavinson group) and registered as an immunomodulatory medicine in Russia and several CIS states.
Its proposed action is immunoregulatory: it increases the functional activity and differentiation of T lymphocytes and is reported to normalize CD4/CD8 balance, and its 'active substances' have been characterized as the short peptides/dipeptides KE (Lys-Glu) and EW (Glu-Trp).
Because it is a registered drug in its home jurisdictions, thymalin has a genuine — if methodologically weak and largely Russian-language — clinical literature, which separates it from pure research peptides that have no human data at all.
The most provocative claim is geroprotective: a long-term observational study by Khavinson and Morozov reported that elderly patients treated with thymalin (often combined with the pineal peptide epithalamin) over 6-8 years showed normalized cardiovascular/endocrine/immune indices, fewer acute respiratory and cardiovascular events, and a roughly 2-fold reduction in mortality versus controls, with even larger reductions in those treated repeatedly.
This is a remarkable result on paper, but it is open-label, non-randomized, single-group, decades old, and has not been independently replicated outside the originating institutes — so it cannot be taken as established.
During the COVID-19 pandemic, the same research network reported unblinded clinical series in which adding thymalin to standard therapy in middle-aged and elderly severe-COVID patients lowered hospital mortality (e.g. ~20% vs ~41% with standard care in one comparison) and improved coagulation/lymphocyte indices and the decline of IL-6, CRP and D-dimer; mechanistic work attributes this to KE/EW dipeptides reducing IL-1β/IL-6/TNF-α release in vitro and to stimulation of hematopoietic stem-cell differentiation into mature CD28+ T lymphocytes.
Animal studies (e.g. bone-marrow precursor and thymic-serum-factor work in aged mice) support an immunorestorative effect, and a rat mandible study found thymalin stimulated local immune and reparative responses.
The honest assessment: thymalin is a real, registered immunomodulator with a plausible mechanism and a non-trivial body of human reports — but the evidence is dominated by small, unblinded, single-center, often Russian-language studies from a closely connected group, with little placebo control, scant Western replication, and headline longevity claims that vastly outrun the rigor of the underlying trials.
It is NOT an FDA-approved drug or a dietary supplement; its long-term safety outside the studied contexts is not well characterized; and the dramatic mortality/longevity figures should be read as hypothesis-generating, not proven.
Thymalin is a thymus-derived polypeptide complex reported to increase the functional activity and differentiation of T lymphocytes. In-vitro work suggests it stimulates hematopoietic stem cells toward mature CD28+ T cells and normalizes T-cell subsets — framed as restoring, not over-driving, immune function.
The active substances are characterized as short peptides KE (Lys-Glu) and EW (Glu-Trp). In-vitro, these are proposed to modulate gene expression and reduce pro-inflammatory cytokine release (IL-1β, IL-6, TNF-α), with EW also reported to interact with the ACE2 axis — but this is mechanistic/in-vitro, not clinical proof.
In LPS-stimulated human PBMCs, thymalin and its dipeptides reduced IL-1β/IL-6/TNF-α by 1.4-6-fold; unblinded COVID-19 series reported faster declines in IL-6, CRP and D-dimer. The proposed route from immunoregulation to reduced hyperinflammation — supported mostly by in-vitro and open-label data.
How Thymalin works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
Thymalin is a registered prescription immunomodulator in Russia/CIS, NOT a dietary supplement — this library does not provide a self-administration protocol. Where it is a registered drug, it is given as an intramuscular injection (typically 10 mg/day for a short course of several days), but any use must be directed by a clinician in a jurisdiction where it is approved.
Can be taken without food
| Form | Type |
|---|---|
| 🧪Lyophilized powder for intramuscular injection (registered drug where approved) | Recommended |
Thymalin is administered by injection. There is no validated oral supplement form; oral peptide would be digested.
Minimum: 1 weeks
Optimal: 2 weeks
Cycling: Not required
Note: Injectable prescription drug — timing follows the clinical dosing course, not supplement-style 'with food' or time-of-day rules.
Dose-response data unavailable. The current published research for Thymalin does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Thymalin is a registered medicine in Russia/CIS, so it has real human studies — but they are dominated by small, unblinded, single-center, often Russian-language reports from a closely connected research group, with little placebo control and scant Western replication. The dramatic mortality/longevity figures are open-label and unverified. It is not FDA-approved or a dietary supplement.
An open-label Russian cohort reported a ~2-fold lower mortality rate over 6-8 years in elderly people treated with thymalin (± a pineal peptide), with fewer respiratory and cardiovascular events. Striking on paper, but non-randomized, unreplicated, and not proof of a longevity benefit.
Unblinded clinical series reported that adding thymalin to standard therapy in middle-aged/elderly severe COVID-19 patients lowered hospital mortality and improved lymphocyte counts and coagulation markers (D-dimer, fibrinogen). Promising but not placebo-controlled or independently confirmed.
In-vitro, thymalin stimulated stem-cell differentiation into mature CD28+ T lymphocytes and reduced pro-inflammatory cytokines. Supports the proposed immunorestorative mechanism — but these are laboratory, not clinical-outcome, findings.
Thymalin is reported to be well tolerated in its studied uses, but rigorous long-term safety data outside Russia/CIS clinical practice are lacking, and grey-market 'research peptide' material has no quality control.
Avoid — safety in pregnancy and lactation is not established.
Only under specialist supervision — thymalin modulates T-cell balance and its net effect in a given condition is unpredictable.
Avoid unregulated sources — identity, purity and sterility are not guaranteed; a registered pharmaceutical product under clinical care is the only defensible route.
As an immunoregulatory agent, thymalin could theoretically interact with immunosuppressants or other immunomodulators (in COVID series it was compared against tocilizumab). Combined use is not well studied and should be clinician-supervised.
COVID-19 reports describe thymalin altering coagulation markers (fibrinogen, D-dimer). Any concurrent use with anticoagulants should be clinician-monitored, though direct interaction data are lacking.
Tip: Administer per clinical protocol; thymalin is reported to be generally well tolerated in its studied uses.
Tip: Stop and seek care if an allergic reaction occurs.
Tip: Long-term safety outside studied contexts is poorly characterized; do not self-administer chronically.
The commonly studied dose of Thymalin is Thymalin is a registered prescription immunomodulator in Russia/CIS, NOT a dietary supplement — this library does not provide a self-administration protocol. Where it is a registered drug, it is given as an intramuscular injection (typically 10 mg/day for a short course of several days), but any use must be directed by a clinician in a jurisdiction where it is approved.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Timing is flexible for Thymalin — consistent daily use matters more than the time of day. Thymalin is injected intramuscularly and dosed as a short course; timing follows the clinical protocol rather than food or circadian considerations.
Thymalin should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are injection-related reactions, hypersensitivity to thymus-derived material, unknown long-term effects. Use caution if any of these apply to you: Not an FDA-approved drug or a regulated dietary supplement — registered as a prescription immunomodulator only in Russia/CIS; use only under a clinician; Known hypersensitivity to thymus-derived peptide preparations; Pregnancy and breastfeeding (not established as safe).
Gonadorelin
Mostly mechanism / observationalA synthetic copy of gonadotropin-releasing hormone (GnRH), the hypothalamic decapeptide that drives the pituitary to release LH and FSH. Honest appraisal: it has genuine, trial-backed roles as a diagnostic agent (the GnRH/gonadorelin stimulation test) and — delivered in pulses by an infusion pump — for inducing ovulation in hypothalamic amenorrhea and spermatogenesis in men with congenital hypogonadotropic hypogonadism. Its now-trendy use in men's TRT clinics (compounded, to 'maintain testosterone/fertility' alongside testosterone, often replacing hCG) is largely off-label and has NOT been validated in controlled trials for that purpose.