Selank

Molecular identity

Sequence

Thr-Lys-Pro-Arg-Pro-Gly-Pro

Formula

C33H57N11O9

Molecular weight

751.9 g/mol

CAS

129954-34-3

PubChem CID

11765600

What it acts on

• Peptidase-mediated clearance — the C-terminal Pro-Gly-Pro extension is what separates Selank from the tuftsin tetrapeptide, and it is described as slowing enzymatic degradation, the stated reason the analogue holds a longer working window in vitro than the parent fragment; no paper in this reference set measures that degradation directly.
• GABA-A receptor and GABAergic signalling — GABA-A receptor binding appears in the summary characterisation of the compound rather than in any primary paper cited here, and the rat withdrawal study benchmarks it against diazepam, a GABA-A positive modulator, reporting the same direction of effect at slightly lower pharmacological activity.
• BDNF expression — hippocampal BDNF is one of the readouts named in the summary characterisation, and the 2026 review groups the peptide with neuroactive peptides reported to raise BDNF and to engage the HGF/c-Met axis relevant to neuroplasticity; neither is primary expression data from this reference set.
• Cytokine and interferon profiles — the parent fragment tuftsin is an endogenous immune-signalling peptide, and immune readouts are listed in the summary characterisation as the reason the molecule is filed with the neuro-immune regulators rather than with pure neuromodulators; no paper in this reference set reports cytokine or interferon data for Selank.
• Amygdala–temporal cortex resting-state connectivity — the human imaging study reports between-group and between-condition differences in coupling between the right amygdala and right-hemisphere fusiform, inferior and middle temporal and parahippocampal cortex, defined in a post-hoc analysis.

What the studies report

Each item below summarises the paper it is numbered to, written from that paper's own abstract. The badge says how the evidence was produced.

1. 1.
   human studyDokl Biol Sci (2020)

   A resting-state fMRI study in 52 healthy participants comparing Selank, Semax and placebo. Imaging was acquired before administration and at two later time points, with the amygdala and dorsolateral prefrontal cortex of both hemispheres set as regions of interest. The authors report between-group and between-condition differences in connectivity between the right amygdala and a right-hemisphere temporal region spanning the fusiform, inferior and middle temporal and parahippocampal gyri. They state the finding came from post-hoc analysis and is described for the first time — an exploratory imaging result in healthy volunteers, with no clinical endpoint and no independent replication in this reference set.

2. 2.
   reviewJ Am Acad Orthop Surg Glob Res Rev (2026)

   A 2026 narrative review of therapeutic peptides written from an orthopaedic perspective. Selank appears only in passing, grouped with semax and dihexa as neuroactive peptides reported to enhance BDNF and HGF/c-Met signalling relevant to neuroplasticity; the review's own subject is tissue repair and it surveys a dozen unrelated peptides. Its closing assessment applies to Selank as much as to the rest: the preclinical work is promising and clinical trials are currently lacking.

3. 3.
   animal modelBull Exp Biol Med (2022)

   Outbred rats in a naloxone-precipitated morphine withdrawal model. A single administration, at a dose the authors describe as anxiolytic, lowered the composite withdrawal index by 39.6%, significantly attenuated convulsive reactions, ptosis and posture disorders, and raised the tactile sensitivity threshold nine-fold against active control. Diazepam, used as the reference comparator, was slightly stronger on both measures (49.3% and a thirteen-fold threshold rise). The design is acute and single-administration, rests on one behavioural model, and carries no mechanistic readout of what mediated the effect.

4. 4.
   animal modelBull Exp Biol Med (2019)

   Male Wistar rats under chronic foot-shock stress, with liver morphology as the endpoint. The stress model produced hydropic degeneration of hepatocytes, a raised nucleus/cytoplasm ratio, focal necrosis and lymphohistiocytic infiltration. All three dose arms reduced the intensity of these changes, and the two higher arms restored the nucleus/cytoplasm ratio, but the largest stress-limiting effect fell on the intermediate arm rather than the highest — a non-monotonic dose response the paper records without explaining. Morphometry only: no biochemical, functional or mechanistic measurement accompanies it, and only male animals were used.

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