Selank and Semax are not variations of the same compound. They come from different parent molecules, are studied for different questions, and sit at different points on the evidence curve. They are grouped together because both were developed in Russia, both are heptapeptides, and both are supplied for laboratory research as intranasal solutions — which is also why they are so often confused.
This page sets the two side by side on what has actually been published. It documents research, not use: nothing here is a recommended amount, schedule or protocol.
Where each one came from
Selank is a synthetic analogue of tuftsin, a naturally occurring immune-modulating tetrapeptide, extended to seven amino acids for stability. It is also referred to as TP-7 in the literature.
Semax is a synthetic analogue of a fragment of ACTH — specifically ACTH(4-10) — with a proline-glycine-proline tail added so it is not broken down as quickly. Despite the ACTH origin, research reports it lacks the hormonal activity of the parent molecule.
So the family resemblance is superficial: both are short synthetic peptides from the same research tradition, built on completely different biological starting points.
What each has been studied for
| Selank | Semax | |
|---|---|---|
| Parent molecule | Tuftsin (immune peptide) | ACTH(4-10) fragment |
| Main research focus | Anxiolytic activity, GABAergic signalling | Cognition, attention, neuroprotection |
| Signalling studied | GABA receptors, BDNF expression, enkephalin degradation | BDNF and NGF expression, dopaminergic and serotonergic systems |
| Clinical context | Anxiety and stress-related research, largely Russian | Stroke recovery and cognitive research, largely Russian |
| Western approval | None — not MHRA, EMA or FDA approved | None — not MHRA, EMA or FDA approved |
| Usual research format | Lyophilised powder or intranasal solution | Lyophilised powder or intranasal solution |
The anxiolytic question — Selank
What distinguishes Selank in the published literature is not that it is reported as anxiolytic, but how it is reported as anxiolytic. Benzodiazepines act on GABA-A receptors with well-documented sedation, cognitive dulling and dependence liability. Research on Selank describes anxiolytic activity without that same profile, which is the reason it continues to attract study.
Published work has examined its influence on GABAergic signalling, expression of BDNF, inhibition of enkephalin degradation, and attention and memory under stress conditions. Human clinical studies exist and are largely published in Russian-language journals, which is a real limitation on how well the evidence is scrutinised internationally.
The full picture, including what was actually administered in each study, is in our Selank research review.
The cognition question — Semax
Semax research centres on neurotrophic signalling. Studies report it influences BDNF and NGF — two factors involved in neuronal growth and survival — and it has been examined for effects on cognition, attention and memory, and for neuroprotective activity in models of cerebral ischaemia.
Its most cited clinical context is stroke recovery, where Russian trials investigated intranasal Semax alongside standard care. As with Selank, most human data is Russian and the compound holds no Western approval.
The detail sits in our Semax research review.
What they have in common
- Neither is an approved medicine in the UK, EU or US. Registration in Russia does not confer approval elsewhere, and outside Russia both are supplied strictly as laboratory research reagents.
- Both are short, fragile peptides. They are supplied lyophilised because a dry powder is stable in a way a solution is not.
- Both have an evidence base weighted towards Russian-language publication, which means less independent replication than a Western-approved compound would carry.
- Neither has an established Western dose, which is precisely why neither of our research reviews offers one.
Formats we supply for research
Both compounds are stocked in the same three formats, so the choice is about how the material is handled in the lab rather than about the compound itself:
- Lyophilised powder — Selank and Semax, sealed vials, reconstituted at the point of use.
- Nasal spray — Selank nasal spray and Semax nasal spray, prepared to order in a 10ml metered bottle.
- Pen refill kit — Selank kit and Semax kit, supplied unmixed with bacteriostatic water, a cartridge and a needle.
Every batch of both is independently tested for HPLC purity and mass-spectrometry identity, and the certificates are published on our lab results page.
So which is which?
Put simply: Selank is the one studied for anxiety-related questions, Semax is the one studied for cognition and neuroprotection. They are not interchangeable, they are not variants of one another, and the published evidence for each answers a different question. Anyone reading about one and assuming it applies to the other is reading about a different molecule.