Doses and routes documented in the published Epitalon literature.

The short version

This page describes the doses, routes, and schedules used in published Epitalon research — not a protocol, and not a recommendation for any person or any purpose. In broad terms: rodent lifespan studies used roughly one microgram per mouse, injected under the skin, for five consecutive days each month rather than daily. Human clinical observations used sublingual administration of a half-milligram daily over twenty days, or parabulbar injection at five micrograms per eye for retinal endpoints. No formal pharmacokinetic study exists in any species. Half-life in humans is inferred from general short-peptide chemistry to be short — probably minutes — but this is not a measured value for Epitalon specifically. The dose heterogeneity across species, routes, and endpoints is substantial, and cross-study extrapolation is not supported by the literature.

What has been studied, and at what doses

Epitalon has been investigated across a wide range of species, routes, and dose levels. The heterogeneity of published dosing protocols makes cross-study comparison and any form of dose extrapolation difficult — a limitation explicitly acknowledged in the 2025 comprehensive review ^[13]. The table below summarizes the major dose-and-route combinations from the primary literature.

Rodent longevity and anti-tumor studies. The dominant protocol across the major SHR mouse and FVB/N HER-2/neu mouse lifespan studies was 1 µg/mouse subcutaneously, administered for 5 consecutive days per month from early life until natural death ^[3][4]. For the C3H/He mouse spontaneous carcinogenesis study, the dose was 0.1 µg/mouse subcutaneously, five times weekly for 6.5 months ^[7]. In rat colon carcinogenesis studies, 1 µg/rat subcutaneously was used during and/or after carcinogen exposure ^[6]. In the SAMP-1 senescence-accelerated mouse study, 1 µg/mouse subcutaneously five times per week monthly was evaluated ^[8].

Drosophila longevity. In Drosophila melanogaster Canton-S imagoes, effective lifespan extension was documented at concentrations from 0.001×10⁻⁶ to 5×10⁻⁶ wt.% in culture medium for males and 0.01×10⁻⁶ to 0.1×10⁻⁶ wt.% for females — dietary supplementation in the food medium ^[5]. The effective doses are in the femtomolar to low nanomolar range by concentration; the remarkable potency relative to melatonin in the same model (16,000-fold lower concentration required) is noted in the original paper without a definitive mechanistic explanation.

Primate neuroendocrine normalization. In senescent rhesus macaques (Macaca mulatta, ages 20–26 years), intramuscular injection at 10 µg/kg for 10 consecutive days produced restoration of evening melatonin synthesis and normalization of cortisol circadian pattern ^[11]. Effects reversed within one month of treatment cessation. No chronic dosing study in primates has been published.

Rat renal model. In Wistar rats with glycerol-induced acute kidney failure, 7 µg/kg intraperitoneally for 7 days documented nephroprotective endpoints ^[13].

Neurological studies. Intranasal Epitalon at 0.5–20 ng in rats increased spontaneous neuronal firing in parietal and frontal neocortex within 5–7 minutes ^[13]. This dose range is several orders of magnitude below the subcutaneous doses used in lifespan studies, reflecting the different pharmacokinetic dynamics of central nervous system delivery via the nasal mucosa.

In vitro cell culture studies. Human fetal fibroblast telomerase studies used concentrations not specified in published abstracts ^[1]; the 2025 Al-dulaimi study used 0.2–1 µg/ml in cancer and normal human cell lines ^[2]; retinal ARPE-19 cell wound-healing studies used 20, 40, and 60 ng/mL ^[19]; bovine oocyte maturation studies used 0.05–0.1 mM ^[20]; immune activation studies documented mitogenic activity at 10⁻¹⁷–10⁻¹⁵ M (femtomolar range) in murine thymocytes ^[13].

Human clinical series. Two human studies have been published by the Khavinson group. In 162 patients with retinitis pigmentosa, 5.0 µg per eye was administered by parabulbar injection for 10 consecutive days ^[12]. In 75 women with accelerated pineal aging features, 0.5 mg/day was administered sublingually for 20 days ^[15]. No dose-escalation study, pharmacokinetic study, or safety trial in humans has been published.

Pharmacokinetics: what is not known

Formal pharmacokinetic characterization of Epitalon in any species is absent from the published literature ^[13]. The following inferences are drawn from structural properties and experimental observations, not from published PK studies.

The peptide's small size (4 amino acids, 390 Da) and two intramolecular salt bridges suggest relatively rapid distribution once absorbed, consistent with the 5–7-minute onset of neuronal activity observed after intranasal dosing in rats ^[13]. Nuclear entry has been confirmed by labeled-peptide experiments in HeLa cells, indicating the compound can reach intracellular compartments. N-terminal pyroglutamate cyclization has been observed in some preparations and can lower the measured molecular mass — a consideration for analytical characterization of commercial materials ^[13].

Oral bioavailability remains unresolved. The compound's claimed stability against hydrolysis in some in vitro conditions is theoretically consistent with oral absorption, and Drosophila lifespan extension was achieved via dietary supplementation ^[5]. However, no formal bioavailability study in a mammalian model has been published. Dendrimer complexes have been studied as potential oral delivery vehicles, but this work has not advanced to in vivo characterization ^[13].

Half-life has not been formally measured. No published human pharmacokinetic study exists. Route selection in the published clinical series (parabulbar injection for retinal endpoints, sublingual for circadian endpoints) appears to reflect mechanistic hypotheses about local vs. systemic delivery rather than documented pharmacokinetic optima.

Stereoisomer pharmacology is unexplored. Eight possible isomers of the four amino acids exist; only the L-amino acid configuration has been investigated ^[13].

Routes studied

The published literature documents eight distinct routes of administration across the Epitalon research record: subcutaneous injection (the majority of rodent longevity and anti-tumor studies ^{[3][4][6][7][8][16]}); intraperitoneal injection (rat renal model ^[13], Drosophila pregnancy study ^[12]); intramuscular injection (primate neuroendocrine study ^[11]); intranasal administration (rat neurological studies ^[13]); parabulbar injection (retinal studies — rat and human ^[12]); oral/dietary supplementation (Drosophila ^[5]); sublingual administration (human circadian gene clinical series ^[15]); and in vitro cell culture addition (fibroblast telomerase, cancer cell lines, ARPE-19 retinal cells, bovine oocytes, murine immune cells ^{[1][2][13][19][20]}).

No route has been systematically compared against another in the same species for the same endpoint. The practical implication is that the route-specificity of Epitalon's effects — which pathways are activated by which delivery approach — is not established.