Semax vs Selank: Which One to Choose (2026)

Semax is for focus and Selank is for anxiety. Both are short Russian-developed peptides given as a nasal spray, and both come from the Institute of Molecular Genetics of the Russian Academy of Sciences, but they start from different molecules and are used for different goals. At RxPepsDirect each is $125 for a 15 mL spray from Optimal Balance Pharmacy, and the Semax/Selank combination spray is $150.

6 min read · Updated September 23, 2026

Dr. Jonathan Snipes, MDMedically reviewed by Dr. Jonathan Snipes, MD and Kim Callender, NP, FNP-BC. Last reviewed September 23, 2026.

What is the difference between Semax and Selank?

Semax is used for focus and cognitive support. Selank is used for anxiety without sedation. Semax is built from a fragment of ACTH, the pituitary hormone that signals the adrenal glands. Selank is built from tuftsin, a small peptide from the immune system. Both have a Pro-Gly-Pro tail added to slow their breakdown, which is why they look alike on paper and why people mix them up.

  • Semax sequence: Met-Glu-His-Phe-Pro-Gly-Pro.
  • Selank sequence: Thr-Lys-Pro-Arg-Pro-Gly-Pro.
  • Both are seven amino acids long and are given as a nasal spray.

How do Semax and Selank compare side by side?

SemaxSelank
Used forFocus, cognitive supportAnxiety, calm focus
Built fromACTH(4-7) fragmentTuftsin
Best-known researchBDNF in animals; stroke recovery in Russian trialsRandomized anxiety trials in Russia
Sedating?No; can disturb sleep if dosed lateNo
Strength2.5 mg/mL, 250 mcg per spray2.5 mg/mL, 250 mcg per spray
Pharmacy direction1 spray each nostril, once daily1 spray each nostril, once daily
Beyond-use date35 days35 days
Price (15 mL)$125$125

The format is identical and the price is identical. The choice comes down to the goal: Semax for focus, Selank for anxiety, the combination spray for both.

What is Semax used for?

Semax is used for focus, learning, and cognitive support. In rats, a single intranasal dose raised BDNF protein in the hippocampus 1.4-fold, and the treated animals learned an avoidance task faster [1]. BDNF is a growth factor tied to learning and memory.

The human research is mostly in stroke recovery. In a Russian study of 110 patients after ischemic stroke, those given Semax had higher blood BDNF levels and better recovery on the Barthel index, a standard scale of daily function [2]. There are no large trials of Semax for focus in healthy adults, so its use for everyday concentration rests on that mechanism and on clinical experience.

What is Selank used for?

Selank is used for anxiety, and it has the stronger human evidence of the two. In a randomized trial of 62 patients with generalized anxiety disorder or neurasthenia, Selank’s anti-anxiety effect was similar to the benzodiazepine medazepam, and Selank also reduced fatigue [3].

A second randomized study of 70 patients added Selank to the benzodiazepine phenazepam. The combination worked faster and cut phenazepam’s side effects, including sedation, memory problems, and fatigue [4]. Both trials were run in Russia, and Western replication is limited.

Can you take Semax and Selank together?

Yes, and the combination spray is the simplest way to do it. The Semax/Selank nasal spray puts 2.5 mg/mL of each in one 15 mL bottle for $150. Buying the two single sprays instead costs $250.

  • Use one format at a time: the combination spray, or a single spray.
  • Adding a single Semax or Selank spray on top of the combination doubles that peptide. RxPepsDirect’s ordering system blocks that pairing.
  • Semax and Selank as two separate single sprays can be ordered together, for patients whose provider wants to dose them differently.

What is the dosage for Semax and Selank?

Optimal Balance Pharmacy’s direction for both is 1 spray in each nostril once daily. Each spray delivers 250 mcg, so that is 500 mcg a day. Russian clinical protocols run Selank in 14-day courses and Semax in 14 to 21 day courses, followed by a break to re-evaluate. Your provider sets the course length at review.

How much do Semax and Selank cost?

Each single spray is $125 and the combination is $150, paid to Optimal Balance Pharmacy at its wholesale price. RxPepsDirect charges a separate $39 medical visit, and the pharmacy charges $15 for overnight shipping.

  • One single spray, first order: $179 ($125 + $39 + $15).
  • Combination spray, first order: $204 ($150 + $39 + $15).
  • A bottle is used for up to 35 days, its beyond-use date, so a single spray works out to about $3.57 a day and the combination to about $4.29 a day for the medication.

Which one should you choose?

  • Choose Selank if anxiety or stress is the main problem, including anxiety that gets in the way of focus.
  • Choose Semax if focus and mental stamina are the goal and anxiety is not an issue.
  • Choose the combination spray if you want both effects in one bottle; it costs $100 less than two single sprays.

For protocol detail, see the Selank protocol guide and the Semax/Selank protocol guide. For the wider category, see peptides for cognitive enhancement.

Are Semax and Selank FDA approved?

No. Neither is FDA-approved in the United States. Both were developed at the Institute of Molecular Genetics in Moscow, and most human research on them was published in Russian journals. In the U.S. they are compounded by a 503A pharmacy and dispensed only with a prescription; RxPepsDirect providers review every order before it is sent to Optimal Balance Pharmacy.

References

  1. Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Res. 2006. PMID: 16996037
  2. Gusev EI, Martynov MYu, Kostenko EV, et al. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018. PMID: 29798983
  3. Zozulia AA, Neznamov GG, Siuniakov TS, et al. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia. Zh Nevrol Psikhiatr Im S S Korsakova. 2008. PMID: 18454096
  4. Medvedev VE, Tereshchenko ON, Kost NV, et al. Optimization of the treatment of anxiety disorders with selank. Zh Nevrol Psikhiatr Im S S Korsakova. 2015. PMID: 26356395

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Frequently asked questions

Is Semax or Selank better for anxiety?
Selank. It is the one studied for anxiety: in a randomized trial of 62 patients with generalized anxiety disorder or neurasthenia, Selank's anti-anxiety effect was similar to the benzodiazepine medazepam (Zozulia et al., 2008). Semax is used for focus and has no comparable anxiety trial.
Is Semax or Selank better for focus?
Semax is the one used for focus. Its best-known research shows it raising BDNF, a protein tied to learning, in the rat hippocampus (Dolotov et al., 2006). Selank can help focus indirectly when anxiety is what gets in the way.
Can you take Semax and Selank at the same time?
Yes. The simplest way is the Semax/Selank combination spray, which puts both in one bottle for $150. Do not use the combination spray together with a single Semax or Selank spray, because that doubles one of the peptides. RxPepsDirect's ordering system blocks that combination.
What are the side effects of Semax and Selank?
Both are generally well tolerated. The most common effects are mild nasal irritation at the spray site and occasional headache. Semax can make it harder to sleep if used late in the day. Tell your provider about psychiatric medications, including lithium, and avoid both during pregnancy or while nursing.
Are Semax and Selank FDA approved?
No. Neither is FDA-approved in the United States. In the U.S. they are compounded by a 503A pharmacy, Optimal Balance Pharmacy for RxPepsDirect patients, and dispensed only with a prescription from a licensed provider.