Semax and Selank are the two best-known Russian "nootropic" peptides, frequently discussed together because they're often described as complementary. Semax (an ACTH fragment analog) is associated with focus, cognition, and neuroprotection; Selank (a tuftsin analog) is associated with calm and anti-anxiety effects. Both are intranasal and neither is FDA-approved.
At a glance
| Semax | Selank | |
|---|---|---|
| Derived from | ACTH(4–10) fragment analog | Tuftsin analog |
| Associated effects | Focus, cognition, neuroprotection | Calm, anti-anxiety |
| Typical route | Intranasal | Intranasal |
| Origin | Developed/used in Russia | Developed/used in Russia |
| FDA status | Not approved | Not approved |
| Western evidence | Limited independent trials | Limited independent trials |
The bottom line
Bottom line: They're usually framed as a pair rather than rivals — Semax leaning toward stimulation/focus and neuroprotection, Selank toward calm and anxiety reduction. Both are used clinically in Russia but lack large independent Western trials, neither is FDA-approved, and both are typically given as nasal sprays.
Frequently asked questions
What's the difference between Semax and Selank?
Semax is generally associated with focus, cognition, and neuroprotection, while Selank is associated with calm and anti-anxiety effects. They are often described as complementary Russian nootropic peptides.
Are Semax and Selank FDA-approved?
No. Both are used as medicines in Russia but are not FDA-approved, and large independent Western clinical trials are lacking. They are sold elsewhere as research chemicals.
How are they taken?
Both are typically formulated as intranasal sprays, partly because they would be broken down if swallowed. We do not publish dosing protocols.
References
Combined peer-reviewed sources from both peptide guides. Inclusion is not endorsement.
- Dolotov OV, Karpenko EA, Seredenina TS, et al. Semax, an analogue of ACTH(4-10), increases brain-derived neurotrophic factor protein in rat basal forebrain. J Neurochem. 2006. Peer-reviewed study
- Gusev EI, Skvortsova VI, Miasoedov NF, et al. Effectiveness of semax in the acute period of hemispheric ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 1997. Peer-reviewed study
- Gusev EI, Skvortsova VI, Chukanova EI. Semax in prevention of disease progression in patients with cerebrovascular insufficiency. Zh Nevrol Psikhiatr Im S S Korsakova. 2005. Peer-reviewed study
- Liu R, Chen Y, Huang H, et al. Semax peptide targets the μ opioid receptor gene Oprm1 to promote deubiquitination and functional recovery after spinal cord injury in female mice. Br J Pharmacol. 2025. Peer-reviewed study
- Sciacca MFM, Naletova I, Giuffrida ML, et al. Semax, a Synthetic Regulatory Peptide, Affects Copper-Induced Abeta Aggregation and Amyloid Formation in Artificial Membrane Models. ACS Chem Neurosci. 2022. Peer-reviewed study
- Glazova NY, Manchenko DM, Volodina MA, et al. Semax, synthetic ACTH(4-10) analogue, attenuates behavioural and neurochemical alterations following early-life fluvoxamine exposure in white rats. Neuropeptides. 2021. Peer-reviewed study
- Zozulia AA, Neznamov GG, Siuniakov TS, et al. Efficacy and mechanisms of action of the peptide anxiolytic selank in generalized anxiety disorder and neurasthenia. Zh Nevrol Psikhiatr Im S S Korsakova. 2008. Peer-reviewed study
- Kolik LG, Nadorova AV, Antipova TA, et al. Selank, peptide analogue of tuftsin, protects against ethanol-induced memory impairment by regulating BDNF. Bull Exp Biol Med. 2019. Peer-reviewed study
- Konstantinopolsky MA, Chernyakova IV, Kolik LG. Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats. Bull Exp Biol Med. 2022. Peer-reviewed study
- Kasian A, Kolomin T, Andreeva L, et al. Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats. Behav Neurol. 2017. Peer-reviewed study
- Vyunova TV, Andreeva L, Shevchenko K, et al. Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein Pept Lett. 2018. Peer-reviewed study
- Fomenko EV, Bobyntsev II, Ivanov AV, et al. Effect of Selank on Morphological Parameters of Rat Liver in Chronic Foot-Shock Stress. Bull Exp Biol Med. 2019. Peer-reviewed study