Semax and Selank are the two most-referenced peptides in nootropic research, and they're often mentioned together. Both are Russian-developed synthetic peptides studied in the brain, but they come from different parent molecules and are studied through different pathways. Here's the breakdown.

The quick answer

Semax is based on a fragment of the hormone ACTH and is studied more around focus, memory and neuroprotection. Selank is based on the immune-peptide tuftsin and is studied more around anxiety and stress-response pathways. Different origins, different emphasis.

What each one is

Semax is a synthetic peptide derived from a fragment of adrenocorticotropic hormone (ACTH 4–10). It's studied in neuropeptide research, notably around BDNF expression and cognition.

Selank is a synthetic analogue of tuftsin, a naturally occurring immunomodulatory peptide. It's studied around anxiolytic-mechanism and stress-response pathways.

Side-by-side

  • Parent molecule: Semax = ACTH fragment; Selank = tuftsin analogue
  • Main research emphasis: Semax = focus, memory, neuroprotection; Selank = anxiety, stress-response
  • Shared ground: both are studied around BDNF and general neuropeptide pathways
  • Handling: both are lyophilised powders — store at −20°C, reconstitute with bacteriostatic water, refrigerate once mixed

These describe fields of scientific study — not claims about effects in humans.

Which one?

As with any research compound, it depends on the pathway a protocol is examining — a study on cognition/neuroprotection references Semax; one on stress-response references Selank. They're often studied side by side rather than as substitutes.

Sourcing in Australia

We hold both Semax and Selank in Australian stock, independently batch-tested with published Certificates of Analysis, dispatched same or next business day. See the results in our CoA Library, and the wider context in our complete guide to research peptides in Australia.

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All products are supplied strictly for laboratory and in-vitro research use only. Not for human or veterinary consumption. This article describes fields of scientific research and is not medical advice or a claim about effects in humans.