What the published literature reports on selank dosage: the 300 µg/kg rodent reference dose, the intranasal clinical record, half-life context, and reconstitution math for a 5 mg vial. Research reference only.
Search volume for "selank dosage" is dominated by vendor charts that state numbers with far more confidence than the underlying literature supports. This page does the opposite: it lays out what doses were actually administered in published Selank research, what units those numbers are in, where the record goes quiet, and the arithmetic for turning a lyophilized vial into a known concentration. It is a literature summary for laboratory reference — not a protocol, not medical advice, and not a human dosing recommendation.
Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro): the endogenous immunoglobulin G fragment tuftsin extended at the C-terminus with Pro-Gly-Pro, a modification made specifically to improve metabolic stability.
Two very different bodies of dosing data exist.
Preclinical. Rodent work clusters tightly around 300 µg/kg (0.3 mg/kg), administered intraperitoneally or intranasally. That figure recurs across independent groups — single-dose intranasal administration in the GABAergic gene-expression work of Volkova and colleagues (Front Pharmacol, 2016), 0.3 mg/kg intraperitoneally in morphine-withdrawal (PubMed 36322304) and ethanol-memory models, and 300 µg/kg/day for five days in comparative mouse pharmacology. It is the reference anxiolytic dose in the animal literature.
Clinical. The anchor is Zozulya et al., 2008 (PubMed 18454096): 62 patients with generalized anxiety disorder and neurasthenia, 30 receiving Selank against 32 receiving medazepam, a benzodiazepine comparator. Anxiolytic effect was reported as comparable between arms, with additional antiasthenic and psychostimulant effects in the Selank group, alongside changes in serum enkephalin degradation parameters. Selank has been studied clinically in intranasal form.
Note what that summary does not include: a milligram-per-day figure. The detailed schedules from the Russian clinical programme sit in Russian-language journals without full English indexing, and the concentrations quoted around the internet are repeated without a traceable source. Where a number cannot be traced to a paper, this page does not print one.
The 300 µg/kg figure is the single most-cited Selank dose, and also the most-misused. Species-to-species dose translation is not linear in body weight — conventional allometric scaling adjusts by body-surface area, and the resulting human-equivalent estimate is a regulatory starting point for first-in-human safety design, not a predicted effective dose. Route compounds the problem: intraperitoneal delivery in a rat and intranasal delivery in a human differ in absorption, first-pass exposure, and the extent of direct nose-to-brain transport. Treat any chart that converts an animal mg/kg straight into a human microgram figure as arithmetic dressed up as evidence.
Small linear peptides of this class are cleared from plasma rapidly, which is exactly why tuftsin was extended with Pro-Gly-Pro in the first place — the extension buys stability against peptidase degradation, not durability on the order of hours. Published human imaging work reflects that short timescale: the 2020 resting-state fMRI study of Selank and Semax in healthy volunteers scanned at baseline and at 5 and 20 minutes after administration, and reported amygdala–temporal-cortex connectivity changes at both post-administration timepoints. Animal studies that look for cumulative effects use daily repeat administration over roughly five to seven days rather than a single exposure. Short apparent duration with repeat-daily cadence is the pattern the literature shows; precise human half-life values are not something this page will assert.
Concentration is arithmetic, and it is the one part of this topic with no scientific uncertainty at all. For a 5 mg lyophilized vial:
| Diluent added | Concentration | 1 unit (0.01 mL, U-100 syringe) | 10 units (0.10 mL) |
|---|---|---|---|
| 1 mL | 5 mg/mL (5000 µg/mL) | 50 µg | 500 µg |
| 2 mL | 2.5 mg/mL (2500 µg/mL) | 25 µg | 250 µg |
| 5 mL | 1 mg/mL (1000 µg/mL) | 10 µg | 100 µg |
For nasal-format research preparations, the relevant volume is the actuation, not the syringe unit: a spray pump delivering roughly 0.1 mL per actuation draws 100 µg from a 1 mg/mL solution and 250 µg from a 2.5 mg/mL solution. Verify the actual actuation volume of the specific pump rather than assuming 0.1 mL.
The full method — diluent selection, adding solvent down the vial wall rather than onto the cake, swirling instead of shaking, and labelling the reconstitution date — is in reconstitution 101, and the unit conversions behind the table are worked through in dosing math. Reconstituted peptide is a cold-chain item with a materially shorter usable window than the lyophilized powder.
Selank's clinical evidence base is small, largely single-country, and thinly represented in English-language peer review. There is no large multi-centre trial, no English-language dose-ranging study establishing a dose-response curve, and no long-term safety follow-up that would support confident statements about chronic exposure. The mechanistic work — GABAergic gene expression, inhibition of enkephalin-degrading enzymes — is genuinely interesting and genuinely preliminary. Anyone presenting Selank dosing as settled is overselling the record.
For mechanism and context, see the Selank research overview; for how it sits beside the other Russian-origin nootropic peptide, see Semax vs Selank. Catalog pages: Selank 5 mg and the Selank 5 mg pen.
What dose of Selank is used in published studies? Rodent studies consistently use 300 µg/kg (0.3 mg/kg), intraperitoneally or intranasally, as the reference anxiolytic dose. Published clinical work has used intranasal administration; specific milligram-per-day schedules from the Russian clinical programme are not reliably available in English-language indexing, so this page does not quote one.
Does 300 µg/kg in rats translate to a human dose? No. Interspecies dose translation uses body-surface-area scaling and produces a safety-oriented estimate for trial design, not a predicted effective human dose. Route differences between intraperitoneal and intranasal administration make a direct conversion even less meaningful.
How long does Selank last? Short. The Pro-Gly-Pro extension improves stability relative to tuftsin, but this class of peptide clears quickly; human imaging work observed effects within 5 to 20 minutes of administration, and animal protocols use daily repeat administration rather than single doses when looking for cumulative effects.
How much diluent should a 5 mg vial get? That depends on the concentration a protocol calls for, and it is pure arithmetic: 5 mg in 2 mL gives 2.5 mg/mL, in which 10 units on a U-100 syringe is 250 µg. See the table above and the dosing math guide.
Is intranasal or subcutaneous the studied route? Both appear in the literature. Rodent studies use intraperitoneal and intranasal administration; published clinical work has used the intranasal route. Comparative bioavailability data between routes in humans is not well established.
