Selank and Semax: Nootropic Peptides Explained

Selank and Semax often show up in online forums as "nootropic" peptides, meaning substances people take hoping to improve focus, mood or memory. Both were developed in Russia and are used there as medicines. In the US, neither is FDA-approved. Here is what we know, and what we do not.

Key takeaways

• Selank and Semax are short lab-made peptides, each seven amino acids long, developed in Russia.
• Selank is mainly studied for anxiety. Semax is mainly studied for stroke and brain function.
• Much of the research is from Russian labs, often in animals, with few large independent human trials.
• Neither is FDA-approved. Semax got a narrow advisory committee vote toward compounding in July 2026, which is not an approval.
• Proven treatments exist for anxiety, attention and memory concerns. Start with a licensed clinician.

What Selank is

Selank is based on tuftsin, a tiny peptide that plays a role in the immune system. Russian researchers added a few amino acids to make it more stable. It is usually described as being given as a nasal spray in Russian studies.

Research suggests Selank may:

• Affect GABA-related genes in the brain, the same broad system many anti-anxiety drugs act on (from animal studies)
• Slow the breakdown of enkephalins, natural calming chemicals in the body (from lab studies)
• Reduce anxiety in people with generalized anxiety disorder and neurasthenia, according to a 2008 Russian clinical study

That human study is often cited, but it was published in Russian, and independent confirmation from large trials is lacking. Our Selank peptide page has a short summary.

What Semax is

Semax is based on a short piece of ACTH, a hormone that normally tells the adrenal glands to release cortisol. The Semax fragment does not have ACTH's hormone effects. Researchers designed it to act on the brain instead.

In Russia, it has been used in stroke care and for some other brain conditions. Research suggests it may:

• Affect brain growth factors such as BDNF in animal studies
• Influence brain networks, according to small imaging studies in people
• Support recovery after stroke, based mainly on Russian clinical reports

As with Selank, the human evidence mostly comes from one country and has not been confirmed in large, independent trials. See the Semax peptide page.

Comparison table

Why "approved in Russia" is not enough

Every country has its own drug review system. A drug approved in one place may not meet another country's standards for evidence. FDA has not reviewed or approved either peptide.

Another issue is the research itself. Many Selank and Semax papers are in Russian, come from a small number of institutes and use designs that are hard to compare with modern Western trials. That does not mean the findings are wrong. It means they need to be repeated by other teams before anyone can say the peptides work.

Where the rules stand in 2026

• Selank: FDA removed Selank acetate from Category 2 of its interim compounding lists in September 2024, after its nominator withdrew. That is not approval.
• Semax: In April 2026, FDA said it would remove Semax from Category 2. In July 2026, its Pharmacy Compounding Advisory Committee narrowly voted to recommend adding Semax to the 503A bulks list, against FDA staff's recommendation. The vote is advisory, and rulemaking would still be needed.

Rules are changing quickly, so ask a licensed pharmacist what applies today. For athletes, unapproved substances can fall under WADA's S0 category. See our WADA guide.

Safety considerations

Reported side effects in studies have generally been mild, but small studies cannot catch rare or long-term problems. Other cautions:

• Effects on mood and brain chemistry could interact with antidepressants, anti-anxiety medicines or stimulants.
• Products sold as "research use only" are not checked for purity or contents.
• Anxiety, poor focus and memory changes can have medical causes, like thyroid problems, sleep apnea or depression, that deserve proper care.

Proven places to start

If focus, mood or memory are your concern:

• See a clinician to rule out medical causes.
• Ask about evidence-based therapy, like cognitive behavioral therapy for anxiety.
• Protect your sleep and get regular exercise, both of which have strong evidence for brain health.
• If medication is right for you, use one your prescriber recommends. You can use the PepSteady app to track doses and how you feel.

The bottom line

Selank and Semax are interesting Russian-developed peptides with some animal and small human research behind them. Neither is FDA-approved, and their evidence has not been confirmed by large independent trials. Talk with a licensed clinician about proven options before considering them.

Sources

• Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in GAD and neurasthenia (PubMed)
• Selank administration affects the expression of some genes involved in GABAergic neurotransmission (PMC)
• Functional connectomic approach to studying Selank and Semax effects (PubMed)
• FDA Panel Backs 6 Peptides for Compounding (AJMC)
• FDA removes certain peptide bulk drug substances from Category 2 (Reed Smith)

Frequently asked questions