Most write-ups of Selank treat the delivery route as a logistics question — nasal spray or subcutaneous injection, whichever you can get. The preclinical literature suggests it may be a pharmacology question instead. In one Russian mouse study, the same dose of Selank given intranasally versus intraperitoneally didn't just produce different blood levels — it moved different receptor systems. That's a specific, testable claim, and it sits awkwardly with the way this peptide is discussed online. Here's what Selank research actually shows about route, what's missing, and where Selank sits in Australia.

What is Selank, and why route matters more here than usual

Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) built from the endogenous immune tetrapeptide tuftsin, with a Pro-Gly-Pro tail added to slow enzymatic breakdown. It was developed at the Institute of Molecular Genetics in Russia and is registered there as Selank 0.15% nasal drops for mild anxiety and neurasthenic states.

Route matters for two reasons. First, short unmodified peptides like this are chewed up fast by plasma peptidases — tritium-labelling work from Zolotarev and colleagues on evenly labelled peptides tracked parent-peptide disappearance in the order of minutes, not hours. Second, intranasal dosing opens a partial nose-to-brain pathway that bypasses the bloodstream entirely, meaning the brain and the body can see quite different exposures from the same milligram figure.

So "Selank, 300 µg/kg" is not one experiment. It's at least two.

The mouse study where the route changed the receptor

The cleanest illustration is a comparison published by Vasil'eva and colleagues, dosing Selank at 300 µg/kg/day for five days in two mouse strains, intranasally or intraperitoneally, then running elevated plus-maze behaviour and radioligand binding to GABA and NMDA receptors.

Two findings stand out:

  • Behaviour split by route. Anxiolytic efficiency was higher after intraperitoneal injection; nootropic (exploratory/learning-type) efficiency was higher after intranasal dosing. A follow-up paper in Neurochemical Journal reported the same pattern across Selank, Semax and Noopept — which is interesting, but also means the effect is being attributed to route generally, not to something specific about Selank.
  • Receptors split by route. In BALB/c mice, intraperitoneal Selank increased GABA-receptor binding sites in the frontal cortex by 38%, with no change in hippocampal NMDA binding. Intranasal dosing did not reproduce that cortical GABA change; the shift appeared instead on the NMDA side.

The caveats that have to travel with it

This is animal work, unreplicated outside the same Russian research network, and strain-dependent: both the behavioural and binding effects appeared in the anxious, low-exploration BALB/c strain and were essentially absent in C57BL/6 mice. Receptor binding-site counts are also not the same thing as a clinical effect — a 38% change in ligand binding in mouse cortex tells you a system has been perturbed, not that a person would feel calmer. Treat this as a mechanistic hypothesis about route, not a dosing instruction.

Selank research in humans has only ever gone up the nose

This is the part worth sitting with. The human evidence base for Selank is three small Russian trials — in generalised anxiety disorder and neurasthenia, some with active benzodiazepine comparators — the most recent from 2015. None are large, none are independently replicated outside Russian-affiliated groups, and none appear in a Western regulatory dossier.

All of them used the intranasal formulation, because that is the registered product. The manufacturer's product information also states an absolute bioavailability of 92.8% via the nasal mucosa with plasma appearance within about 30 seconds — a strikingly high figure for a peptide, sourced from the sponsor rather than from independent published pharmacokinetics, and worth flagging as such.

The practical consequence: injectable Selank has no human clinical data behind it at all. Vials sold for "research" use inherit their dosing conventions from the nasal product and from rodent studies, not from human trials of that route. And if the mouse work is even directionally right, injection and spray may not be interchangeable in effect profile — which makes anecdotal reports across routes hard to pool.

Two claims circulating in vendor copy deserve scepticism: precise percentage comparisons of plasma levels between intranasal and subcutaneous "Selank Amidate" (we could find no primary study supporting these), and the framing of amidated variants as established upgrades. Unverified numbers repeated often enough start to look like data. They aren't. More background sits on our Selank profile and across the wider peptides library.

Selank Australia: is Selank legal in Australia?

The Australian position is narrower than most overseas commentary implies:

  • Not scheduled. Selank does not appear in the Poisons Standard (SUSMP) as a scheduled substance.
  • Still an unapproved therapeutic good. It is not on the ARTG. Anything supplied or advertised in Australia for a therapeutic purpose — including anxiety or cognition — falls under the TGA's unapproved-goods framework, which covers the Special Access Scheme, Authorised Prescriber pathways and compounding, not retail sale. "Unscheduled" is not "approved", and it is not a green light for advertising.
  • Personal importation has conditions and limits, and the realistic risk at the border is seizure rather than prosecution.
  • Sport: Selank is not named on the WADA 2026 Prohibited List. Athletes should still note that S0 (non-approved substances) is written broadly, and that "not listed" is not the same as "cleared".

There is no Australian trial, no ARTG entry, and no TGA evaluation of Selank's efficacy to point to. Anyone describing it as "TGA-legal" is describing an absence of scheduling, not a finding of safety or benefit.

What would actually settle the route question

A single head-to-head human study — intranasal versus subcutaneous Selank, same total dose, with both an anxiety endpoint and a cognitive endpoint, run outside the originating institutions — would resolve more than another decade of rodent work. Until then the honest summary is: the route-dependence signal is real but preclinical, the human evidence is small, dated and nasal-only, and the injectable form is an extrapolation.

We track new Selank publications, registry entries and TGA actions as they appear — join the free updates list if you want the next development with the caveats attached.

FAQ

Is Selank legal in Australia?

Selank is not a scheduled substance in the Poisons Standard, but it is also not on the ARTG — making it an unapproved therapeutic good. It cannot be lawfully advertised or sold for therapeutic use in Australia, and supply would fall under TGA access pathways or compounding.

What is Selank used for?

In Russia it is registered as 0.15% nasal drops for mild anxiety and neurasthenic states. Elsewhere it has no approved use; the human evidence is three small Russian trials, the newest from 2015, with no independent Western replication.

Is intranasal Selank better than injections?

There is no human head-to-head comparison. Mouse work suggests the routes may differ qualitatively — injection favouring anxiolytic effects and GABA-receptor changes, intranasal favouring cognitive/NMDA-side effects — but that is preclinical, strain-dependent and unreplicated outside the original group.

Is Selank banned by WADA?

Selank is not named on the WADA 2026 Prohibited List. Athletes should still be aware that the S0 non-approved-substances category is deliberately broad, so absence from the list is not a guarantee of permitted status.

Sources

Not medical advice. retatrutide.net.au is independent and not affiliated with any manufacturer or supplier. Selank is unscheduled in Australia but remains an unapproved therapeutic good with no ARTG registration; it is registered only in Russia, for mild anxiety.