Selank vs Semax
Tuftsin Analog (Neuropeptide) · ACTH(4-10) Analog (Neuropeptide)
Here is how these two compounds compare, based on published research, not marketing claims.
Selank
Reduces anxiety without sedation or dependence; a tuftsin-derived peptide approved in Russia for anxiolytic use.
Semax
Increases brain-derived growth factors (BDNF, NGF) for cognitive enhancement and neuroprotection; approved in Russia for nootropic use.
Selank
88 studies
6 human trials
Not FDA-Approved
Semax
204 studies
10 human trials
Not FDA-Approved
What it does
Selank
Reduces anxiety without causing sedation, cognitive impairment, or dependence. Modulates the GABA system and enkephalin pathways to calm the stress response while preserving mental clarity.
Semax
Increases brain-derived growth factors (BDNF and NGF) to support cognitive function, memory, and neuroprotection. Derived from a fragment of ACTH but engineered to have zero hormonal activity.
How it works
Selank
Selank is a synthetic heptapeptide derived from tuftsin, a naturally occurring immunomodulatory peptide. It modulates GABAergic signaling (the brain's primary inhibitory system), increases enkephalin activity (the body's own anxiety-reducing peptides), and influences serotonin metabolism. Unlike benzodiazepines, which also target GABA but cause sedation and dependence, Selank achieves anxiolytic effects without those liabilities. It also increases BDNF expression, a growth factor that supports synaptic plasticity and cognitive function.
Semax
Semax is a synthetic heptapeptide based on the ACTH (4-10) fragment with a Pro-Gly-Pro C-terminal extension that eliminates the adrenal hormonal effects of ACTH while preserving and enhancing the neuroprotective properties. It upregulates BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor), two growth factors that drive synaptic plasticity, neuronal survival, and memory consolidation. Semax also modulates dopaminergic and serotonergic neurotransmission, contributing to attention and mood regulation.
How often
Selank
In Russian clinical practice, Selank is administered as a nasal spray. The compound received Russian regulatory approval for anxiolytic use. No FDA-approved product exists. Research protocols outside Russia primarily use nasal administration.
Semax
In Russian clinical practice, Semax is administered as a nasal spray for cognitive enhancement and stroke recovery. The compound received Russian regulatory approval. No FDA-approved product exists. Research protocols outside Russia primarily use nasal administration.
How strong
Selank
Anxiolytic effects documented in Russian human clinical studies with regulatory approval. The absence of sedation, cognitive impairment, and dependence liability distinguishes Selank from conventional anxiolytics. BDNF elevation provides a secondary cognitive support mechanism. The compound has both anxiolytic and nootropic properties in published research.
Semax
Russian regulatory approval for nootropic and neuroprotective indications including stroke recovery. Published human studies document BDNF elevation, cognitive improvements, and neuroprotective effects in ischemic stroke patients. The compound has both preventive (cognitive support) and therapeutic (neuroprotection after injury) research applications.
Main tradeoff
Selank
Russian regulatory approval but limited Western clinical validation. Most published human data is in Russian-language literature with limited English-language replication. The compound has a favorable safety profile in published studies but the evidence base is geographically concentrated. Not FDA-approved. Available through research peptide markets and specialty compounding, not standard Western clinical channels.
Semax
Same geographic evidence concentration as Selank: Russian regulatory approval with limited Western clinical replication. The BDNF and NGF elevation mechanisms are well-characterized, but controlled Western clinical trials are absent. Available through research peptide markets; not through standard Western clinical channels. Not FDA-approved for any indication.
Best for
Selank
- Research on anxiolytic mechanisms that avoid sedation and dependence pathways
- Research on tuftsin-derived peptides and their immunomodulatory plus anxiolytic dual activity
- Research comparing Russian-approved peptide therapeutics to Western anxiolytic standards
Semax
- Research on BDNF and NGF upregulation as a neuroprotective and nootropic strategy
- Research on ACTH-derived peptides engineered to separate neuroprotective from hormonal effects
- Research on peptide-based cognitive enhancement and post-stroke neuroprotection
How to choose
A good fit for Selank
- Research on non-sedating anxiolytic mechanisms that avoid benzodiazepine-type liabilities
- Research on GABAergic and enkephalin system modulation for anxiety
- Research contexts where anxiety reduction is the primary endpoint
A good fit for Semax
- Research on BDNF/NGF upregulation as a nootropic and neuroprotective strategy
- Research on cognitive enhancement and post-stroke neuroprotection
- Research contexts where cognitive function is the primary endpoint
Consider both across time
Selank and Semax are the most commonly paired nootropic peptides in clinical protocols. Selank addresses the anxiety and stress axis; Semax addresses the cognitive function and neuroprotection axis. The combination targets both sides of cognitive performance: reducing the interference from anxiety while enhancing the underlying neural support. Both share nasal administration and Russian regulatory approval. No controlled study has tested the combination, but the non-overlapping mechanisms provide the logic for pairing.
Dosing should be determined by a qualified physician who can evaluate individual circumstances. PSI does not provide personalized dosing guidance.
Official dosing references
- DailyMed(NIH drug labels)
- ClinicalTrials.gov
- PubMed
For readers who want the biology: here is the pathway each compound uses to signal the body. This section is optional. The comparison above covers the practical differences.
▶See the biology
- GABAergic Modulation
- GABAergic Modulation amplifies Enkephalin System Modulation
- GABAergic Modulation modulates Serotonin Metabolism Adjustment
- GABAergic Modulation increases BDNF Expression Increase
- Enkephalin System Modulation connects to Anxiety Reduction; Serotonin Metabolism Adjustment connects to Anxiety Reduction
- BDNF Expression Increase connects to Cognitive Support
- BDNF Upregulation
- NGF Upregulation
- BDNF Upregulation modulates Dopaminergic Modulation
- BDNF Upregulation drives Synaptic Plasticity Enhancement; NGF Upregulation enables Synaptic Plasticity Enhancement
- Synaptic Plasticity Enhancement connects to Cognitive Function Support; Dopaminergic Modulation connects to Cognitive Function Support
- BDNF Upregulation supports Neuroprotection; NGF Upregulation supports Neuroprotection
Selank modulates GABAergic signaling and the enkephalin system to reduce anxiety without causing sedation or dependence.
Semax upregulates BDNF and NGF in the brain, driving synaptic plasticity and neuroprotection through neurotrophic factor elevation.
Research Evidence
Both compounds have Russian regulatory approval and published human studies, though most clinical data is in Russian-language literature with limited English-language replication. Semax has published human data from stroke recovery studies and cognitive enhancement trials. Selank has published human data from anxiety and generalized anxiety disorder studies. The evidence base for both is geographically concentrated in Russian and Eastern European research programs.
- 1.
If the research interest is anxiolytic effects without sedation or dependence risk, selank's GABA-ergic modulation is the more relevant mechanism, semax is not primarily studied for anxiety.
- 2.
If the research interest is neuroprotection or stroke recovery, semax has more targeted data in these contexts, including its Russian clinical approval for ischemic stroke.
- 3.
If the research interest is general cognitive enhancement, both have some supporting data, but semax's neurotrophic factor enhancement (BDNF, NGF) provides a more direct cognitive-relevant mechanism.
- 4.
For both compounds, the reliance on Russian-language evidence should be factored into any research assessment, independent Western replication of key findings would strengthen confidence.
Key Limitations
- •The majority of clinical evidence for both compounds is published in Russian-language journals, limiting accessibility and independent verification.
- •Neither compound has undergone clinical trials registered with Western regulatory agencies.
- •Russian regulatory approval standards and processes differ from FDA/EMA requirements, approval in Russia does not equate to Western clinical validation.
- •Manufacturing and formulation consistency across different sources is not well-documented, raising quality control considerations for research use.
- •Both compounds are administered intranasally, and intranasal bioavailability data is sparse, actual CNS exposure at given doses is not well-characterized.
- •Long-term safety data from controlled studies is not available for either compound.
Community Discussion
PSI monitors discussions across peptide research and biohacking communities. These are reported experiences, not clinical evidence.
Selank
"Selank eliminated my anxiety without the side effects of benzodiazepines"
Plausible but unproven
"Nasal spray is the best way to take it"
Supported by published data
"It stacks well with Semax for cognitive performance"
Anecdotal only
Semax
"Semax improved my focus and cognitive performance"
Plausible but unproven
"It helped with my brain fog after COVID"
Anecdotal only
"The nasal version works within minutes"
Plausible but unproven
Safety Comparison
Both compounds have favorable safety profiles in published studies. Selank is reported as non-sedating and non-addictive, distinguishing it from conventional anxiolytics. Semax is derived from ACTH but engineered to eliminate hormonal activity. Both are administered nasally with no significant adverse effects reported in published research. Neither has long-term Western clinical safety data.
Selank
Approved for clinical use in Russia with reported favorable safety in Russian clinical studies. No significant adverse effects reported in available literature. However, most safety data comes from Russian-language publications with limited independent replication. Intranasal delivery minimizes systemic exposure.
Semax
Approved for clinical use in Russia for stroke recovery and cognitive disorders. Reported safety profile is favorable in Russian studies with no significant adverse effects. Intranasal delivery. Limited Western safety characterization. Does not produce the hormonal effects associated with full-length ACTH.
What the Research Suggests
Selank and semax are complementary neuropeptides with distinct mechanisms, anxiolytic GABA modulation (selank) versus neurotrophic cognitive enhancement (semax). Both have Russian clinical approval and favorable reported safety profiles, but the evidence base for both is limited by its concentration in Russian-language literature with limited Western replication. PSI rates both at Animal Studies, reflecting not a judgment on the compounds' potential but a factual assessment of evidence accessibility and independent validation status. Researchers interested in these compounds should seek out the primary Russian literature (with translation support if needed) and monitor ongoing Western research efforts that may improve evidence ratings in the future.