Selank vs Semax

These two are searched together almost every time, and for once the pairing is sound: they come out of the same Russian research programme, they are both heptapeptides, and they were developed for opposite ends of the same problem.

Selank is a synthetic analogue of tuftsin, extended with a Pro-Gly-Pro sequence that slows enzymatic degradation. Its published character is anxiolytic — enkephalinase inhibition, GABAergic modulation, effects on BDNF expression.

Semax is an analogue of ACTH(4–10), stripped of the hormonal activity of the parent fragment while retaining neurotropic properties. Its literature runs toward BDNF and NGF and toward melanocortin receptor modulation, and its research framing is stimulatory rather than calming.

So the decision is direction, not degree. A question about dampening a stress response and a question about arousal or attention are different experiments, and choosing between them on potency alone misses that entirely.

Two caveats worth carrying into either. Most of the published work on both uses intranasal administration rather than injection, which changes what a comparison of milligram quantities actually means. And the bulk of that literature is Russian-language and older, with limited independent replication outside that tradition.

Both are stored at 2–8 °C. Purity, sizes, price per milligram and current availability in the table above are read from the live catalogue at page load.

Both are supplied for laboratory research only. Neither is sold for human or veterinary use.