Overview
At a Glance
Cognitive peptides — Selank and Semax — are synthetic analogs of naturally occurring peptides, developed at the Institute of Molecular Genetics in Russia. Both have regulatory approval in Russia but not in the US or EU. Selank is derived from the immune peptide tuftsin and targets anxiety and cognitive function. Semax is derived from ACTH(4-10) and targets neuroprotection and cognitive enhancement.
Peptides targeting cognitive function, mood, and sleep represent a niche area of peptide therapeutics. Three peptides have garnered particular interest: Selank, a synthetic heptapeptide with anxiolytic properties; Semax, a synthetic heptapeptide with nootropic and neuroprotective effects; and DSIP (Delta Sleep-Inducing Peptide), a naturally occurring nonapeptide implicated in sleep regulation.
An important context for evaluating these peptides: Selank and Semax were both developed at the Institute of Molecular Genetics of the Russian Academy of Sciences and are approved medications in Russia. However, they have not undergone FDA review and are not approved for clinical use in the United States, Europe, or other Western regulatory jurisdictions. The published evidence base consists primarily of Russian-language clinical literature, with some peer-reviewed English-language publications (Medvedev et al., 2014; Bashkatova et al., 2007).
DSIP occupies a different position — it is a naturally occurring peptide first identified in 1977 from the cerebral venous blood of rabbits during induced sleep. Despite decades of research, its exact physiological role remains debated, and it has never been approved as a medication in any jurisdiction (Kastin et al., 2006).
At a Glance
A quick-reference overview of peptides in this category — key facts, evidence level, and estimated cost.
| Peptide | Expected Results | Evidence | Status | Side Effects | Cost/Mo |
|---|---|---|---|---|---|
| Semax Synthetic ACTH analog, neuroprotective |
|
✓✓✓ Early clinical — approved in Russia, some clinical data | Returning to Cat. 1; approved in Russia/Ukraine |
|
$80–$250 |
| Selank Tuftsin analog, anxiolytic nootropic |
|
✓✓ Limited human — approved in Russia, limited Western data | Returning to Cat. 1; approved in Russia |
|
$80–$250 |
| DSIP Delta sleep-inducing peptide |
|
✓ Mostly preclinical — 1980s studies, mixed results | Research only |
|
$100–$250 |
| Epitalon Tetrapeptide for telomerase/pineal |
|
✓ Mostly preclinical — single research group | Research only |
|
$100–$300 |
Looking for more detail? The full scientific comparison below provides a deeper dive — mechanism of action, evidence analysis, regulatory status, and sourced references for each peptide.
Head-to-Head Comparison
| Feature | Selank | Semax | DSIP |
|---|---|---|---|
| Type | Synthetic tuftsin analog (Thr-Lys-Pro-Arg-Pro-Gly-Pro) | Synthetic ACTH(4-10) analog (Met-Glu-His-Phe-Pro-Gly-Pro) | Naturally occurring nonapeptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) |
| Primary Target | Anxiolytic (anxiety reduction) | Nootropic / neuroprotective | Sleep regulation |
| Mechanism | Modulates GABA, serotonin, dopamine, and norepinephrine systems; influences BDNF expression (Volkova et al., 2016) | Enhances BDNF expression; modulates dopaminergic and serotonergic systems; neuroprotective in ischemia models (Bashkatova et al., 2007) | Proposed modulation of sleep-wake cycles; mechanisms remain unclear (Kastin et al., 2006) |
| Administration | Intranasal (primary); subcutaneous injection | Intranasal (primary); subcutaneous injection | Subcutaneous or intravenous injection; intranasal studied |
| Regulatory Status | Approved in Russia as an anxiolytic. Not FDA-approved. | Approved in Russia for stroke recovery and cognitive enhancement. Not FDA-approved. | Not approved in any country. |
| Evidence Level | Russian clinical trials; limited Western peer-reviewed data (Medvedev et al., 2014) | Russian clinical trials; animal neuroprotection studies in Western journals (Dolotov et al., 2004) | Preclinical studies; small human studies with mixed results (Schneider-Helmert & Schoenenberger, 1983) |
| Side Effects | Reported as well-tolerated; sedation possible (Medvedev et al., 2014) | Reported as well-tolerated; rare nasal irritation (2025) | Limited safety data; generally reported as tolerable in studies (Kovalzon, 2001) |
| Cost | $40–$80/bottle (nasal spray from peptide suppliers) | $40–$80/bottle (nasal spray from peptide suppliers) | $30–$70/vial from peptide suppliers |
Selank
What It Is
Selank (TP-7) is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences by combining the active fragment of tuftsin (Thr-Lys-Pro-Arg), a naturally occurring tetrapeptide involved in immune modulation, with a Pro-Gly-Pro tripeptide that confers resistance to enzymatic degradation. This design extends the peptide's half-life in vivo (Medvedev et al., 2014).
Mechanism of Action
Selank's anxiolytic effects are proposed to involve multiple neurotransmitter systems:
- GABAergic system: Modulates expression of genes involved in GABA neurotransmission, including GABA receptor subunits (Volkova et al., 2016)
- Monoamine systems: Influences serotonin, dopamine, and norepinephrine metabolism in brain regions involved in anxiety and emotional regulation
- BDNF: Increases brain-derived neurotrophic factor expression, which is involved in neuroplasticity and mood regulation
- Immunomodulation: Retains some of tuftsin's immunomodulatory properties, including effects on cytokine balance
Notably, Selank is reported to produce anxiolytic effects without the sedation, cognitive impairment, or dependence associated with benzodiazepines (Medvedev et al., 2014).
Clinical Evidence
- Russian clinical trials: A comparative study in patients with generalized anxiety disorder found Selank comparable to phenazepam (a benzodiazepine) for anxiety reduction, with fewer side effects and no sedation (Medvedev et al., 2014)
- Alcohol withdrawal: Animal studies show Selank reduces anxiety-like behaviors during alcohol withdrawal (Kolik et al., 2014)
- Gene expression: In vitro studies demonstrate Selank modulates GABA-related gene expression in neuroblastoma cells (Volkova et al., 2016)
Limitations: Most clinical evidence is from Russian studies with limited sample sizes. Independent replication by Western institutions is largely absent. The Russian regulatory approval process differs substantially from FDA requirements.
Dosing Context
Selank is not FDA-approved. In Russia, it is marketed as an intranasal solution. Any use should be discussed with and supervised by a qualified healthcare provider. Dosing should be determined by a qualified healthcare provider.
Side Effects
- Reported as well-tolerated in published studies
- No significant sedation, cognitive impairment, or dependence reported
- Nasal irritation possible with intranasal use
- Long-term safety data is limited
Legal Status
- Russia: Approved and marketed as a prescription anxiolytic (nasal spray)
- United States: Not FDA-approved. Not a controlled substance. Available from peptide suppliers as a research chemical.
- EU/UK: Not approved by EMA or MHRA.
Cost
- In Russia: Available at pharmacies at regulated prices
- Research-grade (international): $40–$80 per bottle (nasal spray) from peptide suppliers
- Peptide clinics: $80–$200 per month when obtained through compounding or anti-aging clinics
Semax
What It Is
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is derived from the ACTH(4-10) fragment of adrenocorticotropic hormone, with a Pro-Gly-Pro C-terminal extension for metabolic stability. Like Selank, it was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. It does not possess the steroidogenic (cortisol-stimulating) activity of full-length ACTH (Bashkatova et al., 2007).
Mechanism of Action
- BDNF upregulation: Increases expression of brain-derived neurotrophic factor and its receptor TrkB, supporting neuroplasticity and neuronal survival
- Dopaminergic modulation: Influences dopamine and serotonin turnover in brain regions involved in cognition and attention
- Neuroprotection: In animal models of cerebral ischemia, Semax reduces infarct volume and improves functional recovery (Bashkatova et al., 2007)
- Anti-inflammatory: Reduces neuroinflammation markers in ischemic brain tissue
- Opioid system: Recent research suggests Semax may interact with the μ-opioid receptor pathway, promoting deubiquitination processes relevant to spinal cord injury recovery (2025)
Clinical Evidence
- Stroke recovery: Russian clinical studies report Semax improves neurological outcomes when administered intranasally after ischemic stroke. It is approved in Russia for this indication (Bashkatova et al., 2007)
- Cognitive enhancement: Russian studies report improvements in attention, memory, and cognitive processing speed in various patient populations
- MPTP-induced parkinsonism: Animal studies demonstrate neuroprotective effects against dopaminergic neuron loss in an MPTP model of Parkinson's disease (Dolotov et al., 2004)
- Optic nerve disorders: Approved in Russia for optic nerve atrophy
Limitations: Similar to Selank, the majority of clinical evidence is from Russian literature. Western peer-reviewed publications are primarily preclinical (animal and in vitro studies). No FDA-standard clinical trials have been conducted.
Dosing Context
Semax is not FDA-approved. In Russia, it is marketed as an intranasal solution for several neurological indications. Dosing should be determined by a qualified healthcare provider.
Side Effects
- Reported as well-tolerated in published studies
- Nasal irritation or discomfort with intranasal use
- Rare reports of headache
- Does not produce cortisol elevation despite ACTH structural origin
- No dependence or withdrawal effects reported
- Long-term safety data is limited
Legal Status
- Russia: Approved prescription medication (nasal drops/spray) for stroke recovery, cognitive disorders, and optic nerve atrophy
- United States: Not FDA-approved. Not a controlled substance. Available from peptide suppliers as a research chemical.
- EU/UK: Not approved by EMA or MHRA.
Cost
- In Russia: Available at pharmacies at regulated prices
- Research-grade (international): $40–$80 per bottle (nasal spray) from peptide suppliers
- N-Acetyl Semax and Semax Adamantyl: Modified versions (not approved anywhere) available at higher prices ($60–$120)
DSIP (Delta Sleep-Inducing Peptide)
What It Is
DSIP (Delta Sleep-Inducing Peptide) is a naturally occurring nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. It was first isolated in 1977 by Schoenenberger and Monnier from the cerebral venous blood of rabbits during electrically induced sleep. The peptide is found in both the central nervous system and peripheral tissues, and its exact physiological function remains a subject of debate nearly five decades after its discovery (Kastin et al., 2006).
Mechanism of Action
Despite its name, DSIP's mechanism is not well understood:
- Sleep modulation: Original studies showed DSIP promoted delta (slow-wave) sleep EEG patterns in animal models, but subsequent studies have produced inconsistent results
- Stress response: Some evidence suggests DSIP modulates the stress response, including effects on cortisol and beta-endorphin levels
- Opioid system: Proposed interactions with opioid receptor systems
- Circadian rhythm: May influence circadian oscillators, though the mechanism is unclear
A major review noted that DSIP's name may be misleading — its effects on sleep are neither consistent nor clearly its primary biological function (Kastin et al., 2006; Kovalzon, 2001).
Clinical Evidence
- Sleep studies: Early human studies (1980s) reported improvements in sleep quality and sleep onset in some insomnia patients, but results were inconsistent across studies (Schneider-Helmert & Schoenenberger, 1983)
- Chronic pain: Small studies explored DSIP for chronic pain conditions with mixed results
- Opiate/alcohol withdrawal: Limited data suggests possible utility in managing withdrawal symptoms, but no controlled trials confirm this
- Narcolepsy: One small study reported improvement in narcolepsy symptoms
Limitations: Much of the clinical research on DSIP dates to the 1980s and 1990s and does not meet modern standards for clinical trial design. Results across studies are inconsistent. No recent large-scale trials exist. The peptide has a very short half-life in vivo (~15 minutes), complicating clinical application (Kastin et al., 2006).
Dosing Context
DSIP is not approved for clinical use in any jurisdiction. Dosing should be determined by a qualified healthcare provider. The peptide's short half-life presents pharmacological challenges for clinical application.
Side Effects
- Generally reported as well-tolerated in the limited published literature
- No significant adverse effects consistently reported
- Safety data is extremely limited and outdated
- Long-term safety has not been evaluated
Legal Status
- United States: Not FDA-approved. Not a controlled substance. Available from peptide suppliers as a research chemical.
- Internationally: Not approved for clinical use in any country.
Cost
- Research-grade: $30–$70 per vial (typically 5 mg) from peptide suppliers
- Peptide clinics: $50–$150 per treatment when offered through anti-aging or wellness clinics
Sources & Further Reading
Selank
- Medvedev VE, et al. A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders. Zh Nevrol Psikhiatr Im S S Korsakova. 2014;114(7):17-22.
- Volkova A, et al. GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells. Front Pharmacol. 2016;7:542.
- Kolik LG, et al. Efficacy of peptide anxiolytic selank during modeling of withdrawal syndrome in rats with stable alcoholic motivation. Bull Exp Biol Med. 2014;157(1):52-55.
Semax
- Bashkatova VG, et al. Neuroprotective and antiamnesic effects of Semax during experimental ischemic infarction of the cerebral cortex. Bull Exp Biol Med. 2007;144(1):50-52.
- Dolotov OV, et al. The neuroprotective effects of Semax in conditions of MPTP-induced lesions of the brain dopaminergic system. Neurosci Behav Physiol. 2004;34(4):399-405.
- Semax peptide targets the μ opioid receptor gene Oprm1 to promote deubiquitination and functional recovery after spinal cord injury. 2025.
DSIP
- Kovalzon VM. Delta sleep-inducing peptide. Neurosci Behav Physiol. 2001;31(6):659-666.
- Kastin AJ, et al. Delta sleep-inducing peptide (DSIP): a still unresolved riddle. Peptides. 2006;27(6):1465-1470.
- Schneider-Helmert D, Schoenenberger GA. Delta-sleep-inducing peptide (DSIP): an update. Neuropsychobiology. 1983;9(4):230-234.
This content is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider.
