Selank

What it is

Selank is a synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, built from tuftsin, a natural four-amino-acid fragment (Thr-Lys-Pro-Arg) of the human immunoglobulin G heavy chain, with Pro-Gly-Pro added at the C-terminus to slow its breakdown and lengthen its action [7][8]. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences together with the Zakusov Research Institute of Pharmacology [7]. A 0.15% nasal-drop product based on the peptide was registered by the Russian Federation Ministry of Health in 2009 and is used there as an anxiolytic and nootropic for generalized anxiety disorder and neurasthenia [1]. In the United States it has no approved product; FDA lists “Selank acetate (TP-7)” among nominated compounding substances it once placed in 503A Category 2 [12]. STACK treats it as a not-approved compound.

How it works

The proposed mechanisms come from Russian laboratory work. Selank acted as a positive allosteric modulator of GABA binding in rat brain membranes, and its interaction with benzodiazepine binding was not simply additive [5]. In rats, a single intranasal dose changed the expression of many genes involved in GABAergic neurotransmission within 1–3 hours, in a pattern that overlapped with the effect of GABA itself [6]. In patients with generalized anxiety, blood enkephalin was degraded faster, and Selank inhibited enkephalin-degrading enzymes in plasma, which the authors proposed as a second anxiolytic mechanism [4]. In mice, intranasal and intraperitoneal Selank produced anxiolytic and nootropic effects only in the high-anxiety BALB/c strain, and the two routes changed different receptor markers, suggesting route-dependent pharmacology [10]. The review literature also describes immunomodulatory and antiviral gene-expression effects [7].

What the evidence shows

Human data are limited and come mostly from Russian journals. In a 62-patient study of generalized anxiety disorder and neurasthenia, 30 patients received Selank and 32 received the benzodiazepine medazepam; anxiolytic effects were similar on Hamilton, Zung and CGI scales, and Selank also showed antiasthenic and psychostimulant effects [2]. Reviews state that in clinical studies Selank’s anxiolytic effect was comparable to low-dose benzodiazepines without sedation, muscle relaxation, tolerance or withdrawal, but those summaries cite Russian-language trials we could not read directly [7][8]. A resting-state fMRI study in 52 healthy volunteers found Selank and Semax altered functional connectivity between the right amygdala and right temporal cortex within 20 minutes of injection [9]. Animal work shows anxiolytic effects in high-anxiety mice [3], reduced morphine-withdrawal signs in rats [11], and enhancement of diazepam’s anxiolytic effect under chronic mild stress in rats [8].

Regulatory status

Selank has no FDA-approved product; in FDA’s compounding records it appears only as a nominated bulk drug substance, “Selank acetate (TP-7)” [12][13]. In Russia, “Selank 0.15%” nasal drops were registered by the Ministry of Health in 2009 and approved for medical use [1]. FDA placed Selank acetate in 503A Category 2 in September 2023, the group of nominated substances FDA considers to raise significant safety risks [13]. On September 20, 2024 FDA announced that Selank acetate and four other peptides would be removed from Category 2 because the nominators withdrew the nominations, effective September 27, 2024 [13]. FDA’s current page lists it under “nominated but withdrawn” [12]. It was not reviewed at the December 4, 2024 PCAC meeting, was not among the seven peptides reviewed on July 23–24, 2026, and appears in no category on FDA’s May 14, 2026 nominations list [14][15][16][17]. STACK found no FDA action approving or listing Selank as of Sep 24 2026.

Half-life and what it means for a level curve

STACK has no reference half-life for this compound because no human value has been published; you can enter your own estimate. What exists is animal and in vitro: in rats given tritium-labeled Selank, peptide appeared in blood within the first minute, and blood content had fallen by half at 7 minutes after intranasal administration, while brain content declined more slowly; the in vitro half-life was about 2 minutes [1]. The same review reports detection in plasma 30 seconds after intranasal administration, arrival in brain tissue by 2 minutes, and a clinical effect described as lasting 20–24 hours despite that rapid clearance [1]. Because the parent peptide is gone within minutes but effects are said to persist for a day, a concentration curve would be misleading for Selank. If you enter an estimate, the level would reach ~97% of steady state after about 5 half-lives with regular dosing. STACK’s curve is an estimate from this published half-life, not a blood level.

Reported side effects

Human safety data are sparse and mostly from Russian sources. The 62-patient comparison against medazepam reported anxiolytic efficacy, but the abstract gives no adverse-event rates [2]. Reviews state that in clinical studies Selank was not accompanied by the sedation, muscle relaxation, amnesia, tolerance or withdrawal typical of benzodiazepines, without quantifying other side effects [6][8]. FDA’s assessment is that compounded Selank acetate “may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation and peptide-related impurities” and that FDA “lacks important information regarding any safety issues raised by selank acetate administered to humans” [12]. That safety concern was the basis for its September 2023 Category 2 placement [13]. If you use a compounded Selank product, report anything unexpected to your prescriber, who can file a MedWatch report.

Storage and handling

There is no FDA label for Selank, so the compounding pharmacy’s label governs storage. The Russian product is a nasal-drop solution [1]; compounded U.S. products may be a nasal spray or a lyophilized vial for injection, and each comes with its own pharmacy instructions on refrigeration, protecting from light, and the discard date after opening. Keep a nasal spray upright and capped, and do not share it. For a lyophilized vial, the STACK reconstitution calculator does the volume math from the strength and diluent you enter; it does not suggest a dose. Do not freeze a reconstituted vial unless the pharmacy says so, and do not use a solution that is cloudy or has particles. When in doubt, ask the pharmacist who dispensed it.

What STACK tracks for it

STACK logs each Selank dose exactly as your prescriber wrote it, in mcg, sprays or drops, with the route (intranasal or injection) and the time. Because there is no published human half-life, the estimated level curve stays off until you enter your own estimate, and STACK labels it as yours. You can add a daily anxiety or mood self-rating and a sleep note so you and your prescriber can see whether anything changes over the weeks, plus side effects such as nasal irritation or drowsiness if they occur. STACK keeps bottle or vial inventory so you know when a refill is due and records the schedule your prescriber gave you. It also shows the regulatory status above: registered in Russia, not FDA-approved, and not on any current FDA compounding list [12][17].

The reference half-life in STACK

STACK ships Selank without a default half-life: No human value; in vitro ~2 min and rat tissue data only. You enter your own estimate before a curve is drawn. Measured in: none — rat distribution study and in vitro measurement only.

Estimate only. Modelled from the published half-life you selected and the doses you logged — not a measured blood level. Do not use it to make medication decisions.

Free tools for Selank

Read next

Sources

Every URL below was fetched and checked on 2026-09-24. Bracketed numbers in the text link here.

1. ReviewA New Generation of Drugs: Synthetic Peptides Based on Natural Regulatory Peptides (Kolomin et al., Neuroscience & Medicine 2013)
2. TrialEfficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia (Zozulya et al., 2008)
3. OtherThe anxiolytic action of an analog of the endogenous peptide tuftsin on inbred mice (Seredenin et al., 1998)
4. OtherThe inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity (Zozulya et al., Bull Exp Biol Med 2001)
5. OtherPeptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity (Vyunova et al., Protein Pept Lett 2018)
6. OtherSelank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission (Volkova et al., Front Pharmacol 2016)
7. OtherGABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells (Filatova et al., Front Pharmacol 2017)
8. OtherPeptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats (Kasian et al., 2017)
9. TrialFunctional Connectomic Approach to Studying Selank and Semax Effects (Panikratova et al., Dokl Biol Sci 2020)
10. OtherComparison of pharmacological effects of heptapeptide Selank after intranasal and intraperitoneal administration to BALB/c and C57BL/6 mice (Vasil'eva et al., 2016)
11. OtherSelank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats (Konstantinopolsky et al., 2022)
12. FDACertain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (FDA)
13. OtherFDA Removes Certain Peptide Bulk Drug Substances From Category 2 Of Interim 503A Bulks List And Sets Dates For PCAC Review (Reed Smith via Mondaq, Oct 4 2024)
14. FDAJuly 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee
15. FDAFDA Briefing Document, Pharmacy Compounding Advisory Committee, July 23-24, 2026
16. FDAFinal Summary Minutes of the Pharmacy Compounding Advisory Committee Meeting, December 4, 2024
17. FDABulk Drug Substances Nominated for Use in Compounding Under Section 503A (FDA, updated May 14, 2026)