Semax vs Selank: Two Russian Peptides, Two Different Jobs

Semax and Selank get sold as a pair. They come from the same Russian labs and end in the same three amino acids.

But they were built from different parents and tested for different problems. One is for focus and brain repair. The other is for anxiety.

The short version

• Semax is made from a fragment of ACTH. It is studied as a nootropic and for recovery after stroke. People describe it as stimulating.
• Selank is made from tuftsin, a small immune peptide. It is studied for anxiety. People describe it as calming without sedation.

What each one does in the body

• Semax and BDNF. In rats a nasal dose raised BDNF, the brain's growth factor, in the basal forebrain within 3 hours. (Dolotov 2006)
• Semax and stimulants. In rodents it raised a serotonin metabolite and sharply increased the dopamine release caused by amphetamine. (Eremin 2005)
• Selank and GABA. In rats it changed the expression of 45 genes involved in neurotransmission within an hour, in a pattern similar to GABA itself. (Volkova 2016)
• Both slow the breakdown of enkephalins. In human serum, both peptides inhibited the enzymes that destroy the body's own opioid peptides. (Kost 2001)

What the human studies show

• Semax: in 110 stroke patients it was linked to higher plasma BDNF and faster functional recovery. (Gusev 2018)
• Selank: in 62 patients with generalized anxiety its effect matched the benzodiazepine medazepam, and it also reduced fatigue. (Zozulia 2008)
• Both, in the same experiment: 52 healthy volunteers got Semax, Selank or placebo and had brain scans before and after. Both changed the connectivity of the amygdala, with effects the authors describe as partly shared and partly specific to each peptide. (Panikratova 2020)

Semax and Selank together

This is one of the most searched questions, and there is no study on it. I found no trial that gave people both at once. The brain-scan study gave them to separate groups.

The logic people use is that one sharpens and the other calms. That is a reasonable guess. It is still a guess.

Which one for what

• Anxiety: the trials are on Selank.
• Focus, memory, recovery after brain injury: the trials are on Semax.
• ADHD: neither has been tested. For Semax there is only a hypothesis paper.
• Sleep: no trial for either.

The honest part

All of this rests on small Russian studies. A Belgian control laboratory that found both peptides in seized products noted that, to its knowledge, neither has completed any clinical trials. (Vanhee 2020)

Neither is approved in the US or EU, there is no long-term safety data, and what is sold online is unregulated.

My take

The first peptide I would take is beef gelatin. Run it for a few months, fix your carbs, your sleep and your gut, and only then look at things like BPC-157, GHK-Cu or Selank. A peptide on top of a broken base does very little.

The full evidence for each is in the Semax guide and the Selank guide.

Quick answers

What is the difference between Semax and Selank?

Semax is built from a fragment of ACTH and is studied as a nootropic and for stroke recovery. Selank is built from the immune peptide tuftsin and is studied for anxiety.

Can you take Semax and Selank together?

No study has tested the combination. A brain-imaging study gave them to separate groups of healthy volunteers.

Is Semax or Selank better for anxiety?

The anxiety trials were done with Selank. Semax is described as stimulating and has not been tested for anxiety.

Is Semax or Selank better for ADHD?

Neither has been tested in ADHD. Semax has been proposed as a candidate in one hypothesis paper.