thymalin

calf-thymus extract registered in the ussr in 1982 and never once entered into a trial registry. the largest human dataset belongs to the two men who made it.

tier D · healing · 0 registered trials · 44 yrs

verdict

a calf-thymus peptide extract with 44 years of published clinical reporting and zero registered trials anywhere. the largest human dataset is 266 people, reported by its developers, published twice from one cohort, never checked outside their institute.

if you're asking whether thymalin and thymulin are the same thing — they are not, and the market treats them as one product. thymalin is a heterogeneous calf-thymus extract with no single sequence and no molecular weight. thymulin is a defined nonapeptide, Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn, 858.9 g/mol. two vendor pages sold under the thymalin name publish thymulin's sequence, thymulin's mass and a formula of C33H54N12O15, then print a purity figure of 99 percent or better against it. one page describes the material in its own copy as a natural extract containing multiple bioactive peptides and prints a single-molecule identity three paragraphs later. the conflation reaches the literature too: a 2004 Kyiv paper carries thymalin in its title and thymulin in its English abstract.

if you're asking whether the mortality numbers are real — they are published, they are placebo-controlled, and they are much smaller than 266. the paper describes stratification randomisation, a placebo arm and a double blind, and its mortality arms are 24 and 22 people: six-year all-cause mortality reconstructs to 18 of 22 dead on placebo against 10 of 24 on thymalin. the 4.1-fold figure belongs to a separate 20-person group outside that randomisation. what is missing is confidence intervals, a survival analysis, allocation concealment and dropout accounting, and the second cohort in the same paper, from the Kiev institute of gerontology, prints percentages that do not resolve to whole people. the same dataset was published in Russian in 2002 and in English in 2003, so secondary sources routinely count it twice. both cohorts were reported by the developers under their own names, and nobody outside those two institutes has attempted to reproduce it in 23 years.

if you're asking what the best independently controlled human number is — it belongs to a fraction of thymalin rather than to thymalin. Glu-Trp, one of the dipeptides the developers isolated out of the extract, was licensed west and run as IM862 in a 202-patient double-blind placebo-controlled phase 3 in AIDS-related Kaposi sarcoma. response 23 percent against 21 percent on placebo, p=0.46. median time to progression 16 weeks against 35 weeks on placebo, p=0.012, which the authors hedge to may accelerate progression because the IM862 arm also had significantly less concurrent antiretroviral therapy at baseline, 88 against 96 percent, p=0.042. the same trial found a shorter time to response on drug, 8.5 weeks against 14, p=0.024. a 25-patient renal-cell phase 2 recorded no objective response at all. that programme stopped after 2007, and IM862 is a single dipeptide given intranasally rather than the extract.

based on published evidence and the registry record. not medical advice.

why D-tier

d-tier, and the argument is about who checked rather than about volume. the efficacy answer comes first because it splits: the immune-parameter effect is real and shows up against controls, and the geroprotection number is enormous and has never been checked by anyone who does not stand to gain from it. two corrections to the older version of this rationale, because they were wrong. the flagship 2003 paper does describe stratification randomisation, a placebo control and, verbatim, a double blind. and its mortality arms are 24 and 22 people, not 266. what it truly lacks is confidence intervals, a survival analysis, allocation concealment and dropout accounting, and the kiev cohort inside the same paper prints percentages that do not resolve to whole people against its own denominators. count the rest of the human record: 293 pubmed entries, 13 trial-tagged, eight of those from before 1996, five with no stated sample size. the one modern prospective controlled study is 92 patients, single centre, open label, biomarker endpoints read as within-group fold change from baseline, zero deaths in either arm. a 2022 retrospective prints hospital mortality of 40.9, 28.4 and 20.6 percent with no denominators, which makes those figures unusable rather than favourable. every registry queried on 2026-07-25 returns zero. c is the band for a compound whose mechanism is plausible and whose data is thin, which would fit a preclinical compound waiting its turn in humans. thymalin is not waiting. it has had 44 years, and what came back is a real placebo-controlled result that a single research lineage owns end to end, plus one outside double-blind placebo comparison, on its own glu-trp fraction, that failed on response. layered on top is an identity problem the other d-tier entries do not have, with the marketed product carrying a different compound's sequence, mass and purity claim. f is wrong: f requires fake, a scam, or harm beyond reasonable doubt, and this is a nationally registered preparation with a granted composition patent by its developers and measurable nonspecific immune activity reported by groups in rostov, vladivostok, kharkiv and chieti that the developers do not run. d is the honest middle. the condition for moving is one registered, controlled, independently run trial of the extract itself.

the core tension

the compound has a longer published clinical history than almost anything else on this board and the smallest circle of people willing to vouch for it. forty four years, a national registration certificate, a granted patent held by its developers, and a placebo-controlled double-blind cohort whose mortality arms are 24 and 22 people and whose numbers are large enough to sell a product on. also: no confidence intervals, no survival analysis, no allocation concealment, no dropout accounting, the same dataset published twice, a second cohort inside the same paper whose percentages do not resolve to whole people, zero registered trials in any registry queried, no pharmacokinetics in any species, and no published assay of what is actually in the marketed material. the one time a piece of thymalin was put in front of a placebo by anyone outside the developers' institutes, it lost.

what it is

A peptide extract of calf thymus, developed in Leningrad by Vladimir Khavinson and Vyacheslav Morozov and registered by the USSR Ministry of Health in 1982 under certificate 82/1108/8. It is a mixture, not a single defined molecule. The developers' own granted US patent specifies it as a weight distribution rather than a compound: polypeptides in a 600 to 6,000 Da band, 80 to 90 percent by weight at isoelectric point 3.5 to 6.7 and the remainder at pI 7 to 9. The 2021 clinical paper describes the same material as a complex of thymus peptides with molecular weight up to 10 kDa. Three named fractions appear across the literature: the dipeptides Lys-Glu and Glu-Trp and the tripeptide Glu-Asp-Pro. AMASS DrugCore, queried on 2026-07-25, holds no record for thymalin under any spelling. No SMILES, no InChIKey, no ChEMBL identifier, because a multi-component tissue extract has no single structure to register.

what it does

The measured effects are real, nonspecific, and almost entirely in cells and rodents. In LPS-stimulated human peripheral blood mononuclear cells from four donors, thymalin and its two named dipeptides lowered IL-1 beta, IL-6 and TNF-alpha by 1.4 to 6.0 fold. In cultured human haematopoietic stem cells, CD44 and CD117 expression fell 2 to 3 fold and CD28 rose 6.8 fold. The most informative cell work runs against the extract. An Italian group at Chieti-Pescara and Ancona ran thymalin at 100 ng/mL in THP-1 monocytes alongside four defined Khavinson peptides across three independent experiments. Every defined peptide reduced monocyte adhesion to endothelium. Thymalin increased it. Thymalin was also the reproducible exception to JNK downregulation, and drove the largest release of extracellular vesicles. Khavinson is a co-author on that paper. In rodents the reported effects are broad: tumour growth arrest in rats carrying transplanted sarcoma 45, accelerated reparative osteogenesis in a 48-rat mandibular defect model, raised cytokine output in mice used as an active comparator arm.

origin

One lineage, Leningrad then St Petersburg. Morozov and Khavinson filed the extract patent in 1985, registered the preparation in 1982, and remain authors on the largest human dataset published on it. The manufacturer named in the 2021 clinical paper is Samson-Med LLC. The developers state the order of invention themselves. In their 2013 review they write that the method of building short peptide bioregulators from the amino acid composition of tissue extracts was proposed in 1999, seventeen years after the extract was registered. Thymalin came first. Vilon, Thymogen and the Glu-Asp-Pro tripeptide were carved out of it afterwards, and every one of those fraction patents was filed after 1982. The founding 1982 publication in Voenno-Meditsinskii Zhurnal carries no abstract in PubMed at all.

why researchers are interested

Four decades of published clinical reporting is unusual in this market, and the numbers inside the developers' cohort are large. Mortality reported down 2.0 to 2.1 fold. Acute respiratory disease down 2.0 to 2.4 fold. Almost nothing else on this board has a national registration certificate and a pharmacopoeial history. There is also real independent work. Groups the developers do not run, in Rostov, Vladivostok, Kharkiv and Chieti, have measured something. A rat study is a rat study, and it is not nothing.

does it work

Two answers, and they belong in different sentences. On immune parameters, yes. Every time a group has put thymalin beside a control and measured T cells, the numbers move. In the 2021 randomised COVID-19 study, 42 against 50, T lymphocytes rose 63.8 percent and CD4 rose 88.9 percent from baseline on thymalin while the control arm's T cell parameters, in the authors' own words, did not improve. Those are within-group changes and the paper prints between-group significance only for CRP, D-dimer, ferritin and ESR. One counter-example belongs here too: an Italian group found thymalin was the single agent that increased monocyte adhesion to activated endothelium while all four purified peptides decreased it. On geroprotection, one group measured it, got an enormous number, and nobody else has checked in 23 years. The 2003 paper does describe stratification randomisation, a placebo control and, verbatim, a double blind. Its mortality arms are 24 and 22 people, not 266, and the printed percentages reconstruct to whole people: 18 of 22 dead on placebo against 10 of 24 on thymalin over six years. What that record genuinely lacks is confidence intervals, a survival analysis, allocation concealment and dropout accounting, and the Kiev half of the same paper prints percentages that do not resolve to whole people against their own denominators. The registry answer is unchanged. AMASS TrialCore and a direct ClinicalTrials.gov query both return zero. There is no pharmacokinetic study, no half-life in any species, no dose-ranging work, no systematic review and no published composition assay of the marketed material. The only double-blind placebo-controlled result produced outside the developers' institutes landed on thymalin's Glu-Trp fraction rather than on thymalin, and it was negative: a 202-patient phase 3 with response 23 percent against 21 percent.

claims vs the data

• clinically proven to cut mortality in older people — weak — The source is a single 266-person dataset reported by the compound's developers across two institutes and published twice, in Russian in 2002 and in English in 2003. The design is better than a sceptic would guess and smaller: the full text describes stratification randomisation with a methods citation, a placebo control and, verbatim, that the trial was double blind, and the mortality arms are 24 and 22 people rather than 266. Six-year all-cause mortality reconstructs to 18 of 22 on placebo against 10 of 24 on thymalin. What the record genuinely lacks is confidence intervals, a survival analysis, allocation concealment and dropout accounting; the widely quoted 4.1-fold figure belongs to a separate 20-person group outside the randomisation; and the Kiev cohort in the same paper prints percentages that do not resolve to whole people against its own denominators. No independent replication exists in 23 years.
• backed by four decades of clinical use — partially true — Registration by the USSR Ministry of Health dates to 1982 and the publication record runs continuously since. But 13 of the 293 PubMed records carry a trial tag, eight of those predate 1996, five state no sample size, and no study of thymalin appears in any clinical trial registry indexed by AMASS TrialCore or ClinicalTrials.gov.
• lowers inflammatory cytokines in cultured human cells — supported — In vitro only, in mononuclear cells from four donors. Thymalin and its two named dipeptides reduced IL-1 beta, IL-6 and TNF-alpha by 1.4 to 6.0 fold in LPS-stimulated cells, and an Italian group with Khavinson as co-author measured the same direction on TNF and IL-6 in THP-1 macrophages across three experiments. This is a cell-culture finding and nothing in the record carries it to a clinical outcome.
• restores immune function — partially true — Nonspecific immune activity is measured repeatedly and by groups the developers do not run. Cytokine reductions of 1.4 to 6.0 fold in mononuclear cells from four donors, CD28 up 6.8 fold in cultured stem cells, raised cytokine output in mice. What is missing is the step from these readouts to a clinical outcome anyone has measured against a control.
• the same thing as thymulin — contradicted — Thymulin is a defined nonapeptide of 858.9 g/mol with its own harmonised drug record. Thymalin is an extract specified by its developers as a weight distribution across a 600 to 6,000 Da band with no single mass. Vendor pages print thymulin's sequence, formula and mass under the thymalin name.
• 99 percent or better purity, verified by HPLC — unverified — An area-percent purity figure describes one species. The developers' own patent specifies this material as 80 to 90 percent by weight at pI 3.5 to 6.7 and the remainder at pI 7 to 9, which is what a specification looks like when there is no single species. The rival Soviet extract Taktivin is specified the same way, by molecular weight band plus seven electrophoretic mobility windows. Where a page publishes both a sharp purity number and a single defined sequence, the two claims describe different materials.
• the glu-trp fraction validates the parent extract — contradicted — Glu-Trp was licensed west as oglufanide and IM862 and reached a 202-patient double-blind placebo-controlled phase 3 in AIDS-related Kaposi sarcoma. Response 23 percent against 21 percent on placebo, p=0.46, and median time to progression 16 weeks against 35 weeks, p=0.012. A 25-patient renal-cell phase 2 recorded no objective response. Four US registrations and two Australian, none with posted results, nothing started after 2007.
• a geroprotector that extends lifespan — overreach — The lifespan and tumour-frequency figures that circulate for thymalin come from the developers' own review of rodent work: irradiated mice and rats, SHR and C3H/Sn strains, chemically induced mammary tumour models. Those are rodent results reported in a narrative review by the compound's inventors. The human end of that claim is the 266-person cohort and nothing else.

key facts

• molecular formula: none. a multi-component tissue extract has no single molecular formula. vendor pages print C33H54N12O15, which is thymulin's formula
• molecular weight: 600 to 6,000 Da band per the developers' patent US-5070076-A; described as up to 10 kDa in the 2021 clinical paper. vendor pages print 858.9 g/mol, which is thymulin's mass
• amino acids: not a defined sequence. the fractions named in the literature are the dipeptides Lys-Glu and Glu-Trp and the tripeptide Glu-Asp-Pro
• half-life: not characterised in any species. no pharmacokinetic study appears in the 293 PubMed records
• type: calf thymus peptide extract (cytomedin class), not a defined molecule
• CAS: none assigned to the extract. vendor pages print 63340-72-7 alongside thymulin's sequence; thymulin's usual CAS is 63958-90-7
• 0 registered trials, any registry
• 293 pubmed records, 13 of them trial-tagged
• 266 largest human dataset, reported by its developers
• 1982 year of registration, ussr

frequently asked questions

What is Thymalin?

Thymalin is a peptide extract of calf thymus developed in Leningrad by Vladimir Khavinson and Vyacheslav Morozov and registered by the USSR Ministry of Health in 1982. It is a mixture rather than a single defined molecule: the developers' granted US patent specifies it as a weight distribution of polypeptides across a 600 to 6,000 Da band, and the 2021 clinical paper describes a complex with molecular weight up to 10 kDa. It has no FDA or EMA record.

What does Thymalin do?

In cells it lowers inflammatory cytokines. In LPS-stimulated human mononuclear cells from four donors, thymalin and its two named dipeptides reduced IL-1 beta, IL-6 and TNF-alpha by 1.4 to 6.0 fold. In cultured human haematopoietic stem cells, CD44 and CD117 fell 2 to 3 fold while CD28 rose 6.8 fold. In one 92-patient open-label COVID-19 study the thymalin arm showed larger within-group falls in IL-6, CRP and D-dimer than the control arm. What it does in humans over any longer horizon is not established: the record holds no pharmacokinetic study, no dose-ranging work and no registered trial.

How is Thymalin studied and administered in the literature?

The only modern human regimen documented in a controlled study is 10 mg intramuscular once daily for five days, used in a 92-patient open-label COVID-19 study in St Petersburg. Older Russian-language reports describe course-based intramuscular administration and, in one 1994 paediatric peritonitis report, local wound infiltration at 0.01 percent. There is no FDA-approved dosing protocol because there is no FDA record of the compound.

What are the side effects of Thymalin?

The published record contains no human pharmacovigilance dataset and no adverse-event table, so this cannot be answered from evidence. The closest finding in the literature is an animal one: a 1993 guinea pig study reported that thymalin stimulated allergization to a microbial antigen and established the possibility of allergic reactions to thymalin itself, with repeated injections producing a stronger sensitising effect than a single one. That is an immunogenicity finding in a heterologous animal-protein extract, and it is not a human result. Product identity is a separate and live problem: two vendor pages publish a different compound's sequence and mass under the thymalin name.

Is Thymalin FDA approved?

No. AMASS RegulatoryCore, which indexes FDA NDA and BLA records and EMA centralised marketing authorisations, returns no thymalin record, and AMASS DrugCore holds no drug record for it under any spelling. There is no US label, no orphan designation and nothing to read a section out of. The Russian registration from 1982 sits outside both Western registers, and its absence there is not evidence about it either way. The wider thymic-peptide family is also absent from FDA and EMA: thymalfasin and thymopentin both reach approval stage elsewhere with no FDA or EMA authorisation. What separates them from thymalin is the registered trial base, 41 and 9 against zero.

Is Thymalin the same as thymulin?

No. Thymulin is a defined zinc-dependent nonapeptide, Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn, with a molecular weight of 858.9 g/mol and its own drug record. Thymalin is a heterogeneous extract with no sequence and no single mass. The two are routinely sold as one product: two vendor pages publish thymulin's sequence, mass and formula under the thymalin name and print a purity figure of 99 percent or better against it, and one of those pages describes the material in its own copy as a natural extract containing multiple bioactive peptides. Thymalfasin, thymostimulin and the rival Soviet extract Taktivin sit in the same cluster of names.

related peptides

• thymosin α-1 — the defined thymic peptide with an actual registered trial base
• epithalon — same lab, same playbook, the pineal side of it
• pinealon — another khavinson short peptide graded on a similarly thin base

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.