Vladonix

An oral preparation of low-molecular-weight peptides extracted from calf thymus, designated A-6 in the Khavinson bioregulator line, marketed for immune support on the strength of injectable thymus-extract literature rather than any study of the product itself.

Also referenced as: Vladonix A-6, Vladonix Lingual, Peptide complex A-6, thymus peptide bioregulator, calf thymus peptide complex

Also appears in: Longevity

What is Vladonix?

Vladonix is a natural extract of calf thymus tissue — a fraction of low-molecular-weight peptides isolated from the thymus glands of calves under twelve months, attributed to a process developed at the St. Petersburg Institute of Bioregulation and Gerontology. In the Khavinson bioregulator nomenclature it carries the designation A-6, and it belongs to the “cytomax” branch of that line: the natural multi-peptide organ extracts, as distinct from the synthetic single-sequence peptides sold alongside them. It is sold mainly as hard capsules, with a sublingual liquid marketed under the same A-6 designation.

It is a peptide product, but not a peptide in the sense the rest of this library uses the word. There is no sequence. The label describes a tissue of origin, and the class it belongs to is defined by a molecular-weight cutoff — the cytomedin extraction is described in the originating group’s own literature as yielding fractions of roughly 1–10 kDa, and thymalin as a polypeptide complex below 10 kDa. That is a process description rather than a specification: the contents are an undefined mixture whose composition depends on the source material and the extraction run. Retail listings for Vladonix itself declare an amino-acid profile and a milligram total, not a molecular-weight range.

Vladonix reaches the research market as an imported dietary supplement carrying immune and anti-aging claims. Those claims are borrowed almost entirely from the literature on thymalin, the injectable thymus extract from the same lineage, and are frequently blurred with thymagen/thymogen, the synthetic dipeptide Glu-Trp that was isolated out of that extract and then made by synthesis. Three products, one tissue of origin, three different routes and three different levels of chemical definition — and only the injectable has the human file.

How it works

Every mechanism below is a property of the thymus-extract class. None has been measured for Vladonix itself.

• Thymic peptide fractions act on T-lymphocyte differentiation. Natural thymic peptides isolated from calf thymus by mild acid extraction — the preparation marketed as thymalin — activated T-cell differentiation and T-cell recognition of peptide-MHC complexes, and altered intracellular cyclic nucleotides and lymphocyte IL-2 and interferon secretion (Morozov & Khavinson, International Journal of Immunopharmacology, 1997;19(9–10):501–505). The further framing sold with the capsule — that this offsets the immune decline following age-related thymic involution — is a marketing extension of that work, not a finding reported in it.
• The extract’s activity was narrowed to a defined dipeptide. In the same work, the immunomodulatory molecule L-Glu-L-Trp was separated from the thymalin extract by reversed-phase HPLC and then synthesized as a single-molecule drug (thymogen); a second dipeptide, Vilon, was synthesized alongside it. That result cuts against the bulk-extract premise: if the activity tracks a specific dipeptide, an undefined complex is a less controlled way to deliver it, not a richer one.
• The tissue-specific gene-expression hypothesis. The Khavinson group’s framework holds that short peptides derived from an organ regulate gene expression preferentially in that same organ (Anisimov & Khavinson, Biogerontology, 2010;11(2):139–149). This is the theoretical basis for the whole A-series. It is a proposal advanced in review form by the originating group, not an independently established mechanism.
• An oral bovine thymus extract has one recent controlled preclinical readout. A nuclear-fraction bovine thymus extract fed to aging mice for fourteen weeks raised GABAergic markers — GAD65, GAD67, and GABA-A receptor β2/β3 subunits — and dose-dependently lowered EEG amplitude and cortical power spectral density (El-Idrissi et al., FASEB BioAdvances, 2026;8(2):e70089). It is a different preparation measuring a neurological rather than immune endpoint, in mice, and two of its three authors are salaried employees of the supplement manufacturer that supplied the extract, per the paper’s own conflict-of-interest statement — but it is one of the few controlled experiments on an orally administered bovine thymus extract in the literature at all.

The unresolved step sits between the second and fourth bullets: no published pharmacokinetic work demonstrates that intact peptides from an oral thymus-extract capsule survive gastric and pancreatic digestion, cross the intestinal epithelium, and reach thymic or lymphoid tissue in a form that could produce the effects attributed to the injectable preparation.

Research status

Nothing has been published on Vladonix itself. A PubMed search for the product name returns zero records. ClinicalTrials.gov has no registered study of Vladonix, and none for thymalin either — while the same registry returns 88 studies for thymosin, so the absence reflects these preparations specifically rather than a registry blind to thymic peptides. DailyMed likewise carries no label for Vladonix or thymalin; the thymus-containing entries in that database are homeopathic and multi-ingredient glandular preparations, which establish no efficacy for this compound.

The human study the claims rest on is injectable, unblinded, and unreplicated. Khavinson & Morozov followed 266 elderly subjects for six to eight years on annual courses of injectable thymalin, epithalamin, or both (Neuro Endocrinology Letters, 2003;24(3–4):233–240). The authors reported a 2.0–2.4-fold reduction in respiratory illness, and mortality reductions of 2.0–2.1-fold for thymalin alone, 1.6–1.8-fold for epithalamin alone, and 2.5-fold for the combination; a subgroup given six consecutive annual courses of the combination was reported at 4.1-fold. The limitations are structural, not incidental: the study was not randomized and not blinded, it was conducted and reported by the group that developed and commercializes the preparations, it has never been independently replicated outside Russia, and a 4.1-fold mortality reduction is an effect size no geroprotective intervention has reproduced under controlled conditions. It also tested injections, not capsules.

The animal work is older and modest in scope. Low-molecular-weight thymus and pineal factors were assessed for effects on lifespan and spontaneous tumor development in female mice started at different ages (Anisimov, Loktionov, Khavinson & Morozov, Mechanisms of Ageing and Development, 1989;49(3):245–257).

Recent clinical reporting is adjunctive and open-label. Thymalin was described as an addition to standard care in hospitalized COVID-19 patients (Khavinson et al., Stem Cell Reviews and Reports, 2021;17(1):285–290), and its two constituent dipeptides — KE (Lys-Glu, marketed as Vilon) and EW (Glu-Trp, marketed as thymogen/thymagen) — were examined for effects on gene expression relevant to COVID-19 pathogenesis in a molecular-modeling and bioinformatic study (Linkova et al., International Journal of Molecular Sciences, 2023;24(17):13377). Neither is a randomized controlled trial, and neither tested an oral product.

The closest controlled evidence for the oral format comes from outside the Khavinson lineage. Thymomodulin, an Italian oral calf-thymus derivative, was tested double-blind in children with recurrent respiratory infections, with a reported drop in monthly infection frequency and a rise in salivary IgA in the treatment arm only (Fiocchi et al., Thymus, 1986;8(6):331–339). It is a different preparation, in a pediatric population, from a small trial four decades old.

Where the class was assessed systematically, the verdict was weak. A systematic review of 72 placebo-controlled randomized trials of immunostimulants for preventing pediatric respiratory infections, covering 12,229 children, found roughly a 39–40% reduction in infection episodes — though that estimate pooled only 38 of the 72 trials, and the reviewers graded the efficacy evidence as low, citing considerable-to-substantial heterogeneity, unclear risk of bias across all domains in 32 of the 72 trials, and adverse-event reporting in only 14 of 72 (Berber et al., World Allergy Organization Journal, 2022;15(9):100684).

Common dosage forms

• Oral hard capsules, the primary format, typically sold in 20- and 60-capsule boxes.
• Labeled content of roughly 0.215 g per capsule total mass, with the thymus peptide complex as the declared active ingredient. Listings commonly state 10 mg of peptide complex per capsule, but declared amounts vary between sellers and no independent assay is published.
• A sublingual liquid is also sold under the same A-6 name (“Vladonix Lingual”), with a declared 10 mg of peptide complex per millilitre. It carries the same evidentiary gap as the capsule and no separate study of its own.
• A-6 product designation on manufacturer packaging, used across the cytomax line to identify the source organ.
• No injectable or compounded form of this product exists. The injectable thymus extract is thymalin, a separate preparation; the synthetic Glu-Trp dipeptide is sold as thymagen/thymogen in lyophilized and nasal-spray formats.

This section describes formats only and is not dosing guidance.

Key considerations

• No approval anywhere in the United States. Vladonix is neither an approved drug nor a compounded preparation; it enters the country as an imported dietary supplement. Under the FDA rule on cattle-derived materials, the prohibited “specified risk materials” are brain, skull, eyes, trigeminal ganglia, spinal cord, vertebral column, and dorsal root ganglia from cattle 30 months and older, plus tonsils and distal ileum from cattle of any age. Thymus appears on neither list, so the preparation is not a prohibited cattle material — that exclusion turns on the tissue, not on the animal’s age, and the twelve-month sourcing claim does no regulatory work here. The broader caution about bovine glandular supplements is nonetheless documented, including in correspondence noting that imported-tissue restrictions written for food and medical products did not extend to dietary supplements (Norton, New England Journal of Medicine, 2000;343(4):304–305).
• The evidence transfer is the central weakness. Essentially every claim made for Vladonix originates in studies of injectable thymalin. Route, preparation, and delivered quantity all differ, and there is no bridging pharmacokinetic or bioequivalence data connecting the capsule to the injection. Reading the injectable literature as evidence for the oral product is the single largest interpretive error in this category.
• Composition cannot be verified by the usual means. For a synthetic peptide, HPLC purity and mass spectrometry establish identity and content against a known sequence. For an undefined organ extract there is no target sequence to confirm, no purity number that means anything comparable, and no established certificate-of-analysis convention. Batch-to-batch consistency is an assumption, not a measurement.
• Independent replication is essentially absent. The human data on this family was generated, published, and interpreted by the group that developed the preparations. When independent reviewers pooled the wider immunostimulant class, the efficacy evidence was graded low and risk of bias was unclear in nearly half the included trials (Berber et al., 2022). Safety data across that literature is thinner still — most trials never reported adverse events at all.
• The naming is a persistent source of error. Vladonix is A-6, the thymus preparation; A-3 in the same product line is Ventfort, the vascular preparation, and the numbers are frequently transposed in secondary listings. It is also distinct from thymalin (injectable extract), thymagen/thymogen (synthetic Glu-Trp), and from thymosin alpha-1 (thymalfasin) and thymosin beta-4 — the last two being defined molecules with entirely separate regulatory and clinical trial histories that searches for “thymus peptide” will pull in indiscriminately.