Selank

Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a synthetic heptapeptide analogue of tuftsin — an endogenous immunomodulatory tetrapeptide fragment of IgG — with a C-terminal Pro-Gly-Pro tripeptide that dramatically extends its biological half-life and independently contributes anxiolytic activity. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences.

The anxiolytic mechanism involves positive allosteric modulation of GABA-A receptors in anxiety-related brain regions including the amygdala, hippocampus, and prefrontal cortex. Critically, Selank modulates rather than directly activates the GABA-A receptor, enhancing endogenous GABA signaling without producing the sedation, cognitive impairment, tolerance, or addiction liability characteristic of benzodiazepines. This allosteric mechanism is akin to how neurosteroids fine-tune GABAergic tone — a fundamentally different pharmacological approach from orthosteric benzodiazepine binding.

Beyond GABAergic anxiolysis, Selank upregulates BDNF expression in the hippocampus and prefrontal cortex, promoting neuroplasticity and cognitive resilience. It also inhibits enkephalin-degrading enzymes (aminopeptidases and neprilysin), extending the half-life of endogenous opioid pentapeptides involved in mood stabilization. The tuftsin core additionally confers immune-modulating properties — macrophage activation, cytokine regulation (IL-6, TNF-α) — at sub-anxiolytic doses, suggesting this is an independent pharmacological effect rather than secondary to CNS action. This tri-modal profile (anxiolytic + nootropic + immunomodulatory) is unique among available research peptides.

Selank was developed in the late 1990s at the Institute of Molecular Genetics in Moscow as part of a program to design peptide-based anxiolytics that retained the efficacy of benzodiazepines without their addiction and sedation liabilities. It was approved in Russia as a prescription anxiolytic and nootropic medication and has been used clinically in Russian-speaking countries since the early 2000s.

The peptide has attracted growing research interest in Western nootropic and biohacking communities as an alternative to traditional anxiolytics, particularly for stress-related cognitive impairment and anxiety disorders where benzodiazepine use carries unacceptable risk. Preclinical studies have documented effects on GABA release, serotonin metabolism, and BDNF expression. As with Semax, independent Western clinical trial data remains limited, and the majority of clinical evidence derives from Russian-language publications and observational studies.

Store lyophilized Selank at -20°C in a light-protected, desiccated container. The Pro-Gly-Pro C-terminal extension provides significant resistance to aminopeptidase degradation; stability exceeds 18 months under optimal conditions. The peptide is relatively robust during brief room-temperature handling.

For intranasal research, reconstitute in sterile saline (not BAC water) and store in a nasal spray device at 2–8°C for up to 30 days. The intranasal route is the primary research administration method and achieves rapid CNS penetration. For subcutaneous protocols using BAC water, store at 2–8°C and use within 21 days. Selank is typically researched in 2–4 week cycles followed by a 1–2 week washout period to prevent tachyphylaxis, though tolerance development is reported to be minimal compared to benzodiazepine anxiolytics.