Semax vs Selank
Both peptides emerged from the same Russian Academy of Sciences programme in the 1990s and are routinely studied together. The mechanistic overlap is real, but the practical differences are sharp enough to make the choice obvious once you know your research endpoint.
At a glance
| Semax | Selank | |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent molecule | ACTH(4-10) fragment | Tuftsin (Thr-Lys-Pro-Arg) |
| Primary endpoint | Cognition, attention, neuroprotection | Anxiolysis, anti-asthenia, immunomodulation |
| Mechanism (primary) | BDNF/NGF induction | Enkephalinase inhibition |
| Route | Intranasal | Intranasal |
| Onset | Hours to days | 30–60 min for anxiolytic feel; days for cumulative effect |
| Clinical use (Russia) | Stroke recovery, cognitive impairment | Generalised anxiety, adjustment disorder |
| UK status | Research chemical | Research chemical |
When researchers pick one over the other
Reach for Semax when…
- · The endpoint is memory, learning, or sustained attention.
- · The research model is ischaemic neuroprotection or post-stroke recovery.
- · You want BDNF/NGF induction as the molecular handle.
- · The protocol prioritises cognitive performance under load.
Reach for Selank when…
- · The endpoint is anxiety, stress reactivity, or anti-asthenic effect.
- · You want anxiolysis without sedation or motor impairment.
- · The mechanism of interest is enkephalin-system modulation.
- · Immune-axis modulation is part of the research question.
The Semax + Selank stack
Combining the two peptides is one of the most-replicated approaches in published Russian research — and the rationale is straightforward: the mechanisms are different enough that there is little redundancy. Semax drives BDNF/NGF induction and cognitive performance; Selank elevates endogenous enkephalin tone and dampens anxiety without affecting alertness. Stacked, they cover both axes of the cognition-mood interaction. Most published protocols stagger administration (Semax earlier in the day, Selank spread or pre-stressor) rather than co-administering.