✓ Medically reviewed by  ·  Last reviewed: May 2026

Morgan Ellis

Pharmacy Researcher · 8 years experience

Pharmacy researcher with 8 years reviewing clinical drug information, generic formulation equivalence, and international pharmaceutical standards. Focuses on patient-facing accuracy in medication education.

Best Nootropic Peptides: Semax, Selank, DSIP and Adamax Compared

The nootropic / CNS peptide cluster is the smallest of the seven peptide research families but covers a distinct research scenario: short peptides that cross the blood-brain barrier and produce measurable effects on attention, anxiety, sleep, or cognitive performance. Most of the published research originates in Russian academic-medicine literature (Semax and Selank are both Russian-developed regulatory peptides with documented Russian Ministry of Health approval for specific clinical indications), with a separate Western research arm focused on mechanism studies and translational neuroscience.

Of the 39 research peptides on the MedsBase peptide hub, four sit firmly in the nootropic cluster, with two additional adjacent compounds (NAD⁺ for cellular-energetics research and MOTS-c for mitochondrial-metabolism) that have cognitive-research crossover and are worth surfacing here.

How to use this hub

• Attention / cognition research: Semax (the most-studied of the cluster).
• Anxiety / anxiolysis research: Selank (the GABA-modulating tuftsin analogue).
• Sleep research: DSIP (delta sleep-inducing peptide; mechanism is sleep-phase modulation).
• Emerging nootropic research: Adamax (under-published but increasing interest).
• Cellular / mitochondrial energetics with cognitive crossover: NAD⁺, MOTS-c.

1. Semax (ACTH 4-7 analogue; the most-published nootropic peptide)

Mechanism class: Synthetic heptapeptide based on ACTH 4-7 / 4-10 motif · View product · Full research guide

Semax is the heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro — a synthetic analogue of the corticotropin (ACTH) 4-7 sequence with two C-terminal additions (Pro-Gly-Pro) that confer enzymatic stability without changing the core ACTH activity. Mechanistically, Semax does not have ACTH receptor activity (the steroidogenic activity is in the N-terminal portion of native ACTH); the 4-7 fragment retains the CNS-active arm of ACTH activity, working through BDNF / NGF modulation, dopaminergic system effects, and direct effects on attention and stress-response neural circuits.

Russian published literature documents Semax effects in stroke recovery, ADHD-related attention deficits, and acute stress-response modulation. Western mechanism research has confirmed BDNF / NGF upregulation in animal models. The molecule is nasal-formulation-friendly; the published research uses both intranasal and subcutaneous routes, with intranasal dominating Russian clinical-research applications.

Pick for: attention / cognitive-research protocols; BDNF / neurotrophic-factor research; the comparator / reference compound for any nootropic-peptide research design.

2. Selank (tuftsin analogue; anxiolytic-research compound)

Mechanism class: Synthetic heptapeptide tuftsin analogue · View product

Selank is a synthetic analogue of tuftsin — a tetrapeptide cleaved from the heavy chain of IgG with immunomodulatory and CNS activity. The Selank molecule extends the tuftsin core with three additional residues (Pro-Gly-Pro) for enzymatic stability, similar to the Semax construction. Mechanism research shows Selank acts as a GABA-system modulator with anxiolytic activity, but without the sedation, dependence, or cognitive-impairment profile typical of benzodiazepine-class drugs. Russian published literature documents Selank effects in generalised anxiety, attention disorders, and stress-response modulation. Western mechanism research has confirmed GABA-system involvement with additional effects on enkephalinase modulation.

Like Semax, Selank is nasal-formulation-friendly with both intranasal and subcutaneous published routes. Russian Ministry of Health registration covers generalised anxiety disorder; no Western regulatory approval exists.

Pick for: anxiolytic-research protocols where non-benzodiazepine mechanism is the design constraint; GABA-system mechanism research; stress-response neuroscience.

3. DSIP (delta sleep-inducing peptide; sleep-phase research)

Mechanism class: Nonapeptide; sleep-phase modulator · CAS: 62568-57-4 · View product

DSIP is the most-researched sleep-focused peptide in the CNS literature. The molecule was originally isolated from cerebral venous blood of sleep-deprived rabbits in the 1970s by Schoenenberger and Monnier — the discovery that established that endogenous peptide mediators of sleep biology exist. Mechanistically, DSIP does not have benzodiazepine-style or melatoninergic activity; the published mechanism literature is fragmented but the consistent finding is sleep-phase modulation (specifically, delta-wave / slow-wave-sleep phase deepening) rather than sleep initiation or sedation.

The molecule has been investigated in protocols spanning insomnia research, chronic-pain-related sleep disturbance, alcohol-withdrawal sleep dysregulation, and circadian-rhythm research. Subcutaneous and intranasal routes are both published.

Pick for: sleep-architecture research (specifically slow-wave-sleep endpoints); circadian-rhythm protocols; sleep-disturbance research models.

4. Adamax (emerging nootropic research compound)

Mechanism class: Research compound; not formally CAS-registered · View product · Full research guide

Adamax is an emerging nootropic-research compound investigated as a Semax follow-on. The published mechanism literature is substantially narrower than Semax’s — Adamax sits at the frontier of nootropic-peptide research rather than the established core. The compound is not formally CAS-registered (a research-compound flag worth noting; the MedsBase catalogue follows the convention of labelling this fact explicitly rather than substituting an arbitrary identifier). Researchers including Adamax in protocol design are typically doing so as the experimental arm alongside Semax as the established-reference comparator.

Pick for: frontier nootropic-research protocols; Semax-comparator research designs; mechanism-novel cognitive-research scenarios.

5. NAD⁺ (cellular energetics with cognitive-research crossover)

Mechanism class: Nicotinamide adenine dinucleotide; redox cofactor · CAS: 53-84-9 · View product · Full research guide

NAD⁺ is the central redox cofactor in cellular metabolism — not a peptide in the conventional sense but included on the peptide catalogue and in this hub because of its substantial research applicability for cognitive / neural-energetics endpoints. Age-related cognitive decline is associated with falling NAD⁺ levels in neural tissue; restoring NAD⁺ (via direct administration or via NAD⁺ precursors like NMN and NR) is studied as a research intervention for cognitive-aging models. The mechanistic link is straightforward: every neural ATP-producing pathway depends on NAD⁺, and NAD⁺-dependent enzymes (sirtuins, PARPs) regulate gene expression and DNA repair in ways relevant to neural-cell maintenance.

Direct NAD⁺ administration in published research uses IV or SC routes; oral bioavailability is limited because NAD⁺ is degraded in the gut.

Pick for: cellular-energetics-mediated cognitive research; sirtuin-pathway protocols; cognitive-aging research models.

6. MOTS-c (mitochondrial-derived peptide with cognitive-research crossover)

Mechanism class: 16-amino-acid mitochondrial-derived peptide; AMPK activator · View product

MOTS-c is the most-studied mitochondrial-derived peptide and is included in this hub because of its cognitive / neural-metabolic-research applicability. MOTS-c levels decline with age in parallel with mitochondrial dysfunction; the compound activates AMPK signalling in skeletal muscle, adipose tissue, and (relevant here) in neural tissue. The neuroprotective and cognitive endpoints in published research are smaller in absolute effect size than the direct CNS-active peptides (Semax, Selank, DSIP) but the mechanism is upstream — modulating cellular energetics rather than receptor pharmacology. Useful in research scenarios where the question is mitochondrial / metabolic substrate of cognition rather than receptor-pharmacology.

Pick for: mitochondrial-mediated cognitive research; neural-energetics protocols; cognitive-aging research where the upstream metabolic question is the design driver.

Comparison table

The Russian regulatory-peptide context

A research-context detail worth surfacing: Semax and Selank are both registered medications in Russia, approved by the Russian Ministry of Health for specific clinical indications (Semax for stroke rehabilitation and attention disorders; Selank for generalised anxiety disorder). Neither has Western regulatory approval. The Russian approval framework is real and the underlying published clinical-research literature is substantive — both compounds have decades of human research data, primarily published in Russian-language academic journals and translated piecemeal in the Western literature. For research scenarios that need some regulatory precedent (even if not FDA/EMA), Semax and Selank are the cluster’s strongest options. The research-grade material on the MedsBase catalogue is the same molecule but is not the finished pharmaceutical product registered with Russian regulators — it is sold for laboratory research use only.

Frequently asked research questions

Why are Semax and Selank both heptapeptides with similar C-terminal extensions?

The Pro-Gly-Pro C-terminal extension on both molecules is a designed-for-stability addition. Native ACTH 4-7 (the Semax core) and native tuftsin (the Selank core) are both rapidly degraded by aminopeptidases in plasma. Adding Pro-Gly-Pro to the C-terminus blocks the enzymatic cleavage site, extending half-life from minutes to a window long enough to support research-protocol dosing. The technique is one of the cleanest examples in peptide pharmacology of structural modification preserving target activity while engineering away the stability problem.

What’s the difference between Semax and Selank in practical research terms?

Different receptor systems, different endpoints. Semax acts primarily through BDNF / NGF upregulation and dopaminergic system effects — the endpoint is attention, cognition, stress-response modulation. Selank acts primarily through GABA-system modulation with enkephalinase effects — the endpoint is anxiolysis, anxiety reduction, generalised tension. Protocols studying attention or cognitive performance use Semax; protocols studying anxiety or stress-response use Selank. The two are sometimes paired in research designs that need both arms.

Is DSIP actually a sleep inducer or just a sleep-phase modulator?

Mostly a sleep-phase modulator. DSIP does not produce sedation in the benzodiazepine sense; published research consistently shows the compound deepens slow-wave (delta) sleep when administered to subjects already in or entering sleep, but does not initiate sleep in awake subjects. This is a meaningful distinction: protocols studying sleep architecture and slow-wave-sleep-specific endpoints fit DSIP’s actual mechanism; protocols looking for a research-grade sleep initiator should look elsewhere.

Adamax has limited published literature — why is it on this list?

Because the cluster is small (only four CNS-active peptides on the catalogue) and Adamax is the most-discussed frontier compound within that cluster. The published literature is genuinely thinner than Semax / Selank / DSIP, and the research-grade label reflects that the compound is not formally CAS-registered. The honest framing in the dedicated Adamax research guide covers what is known and what is not. Researchers including Adamax in a protocol are typically doing so as the experimental arm against Semax as the established-reference comparator.

Why include NAD⁺ and MOTS-c on a nootropic-peptide hub?

Because cognitive-research protocol design increasingly involves the mitochondrial / cellular-energetics arm alongside the receptor-pharmacology arm. NAD⁺ declines in neural tissue with age, and the published literature on cognitive-aging research has substantially shifted toward energetics-based interventions over the past decade. MOTS-c specifically — a mitochondrial-derived peptide that activates AMPK signalling — bridges the metabolic and the cognitive research literatures. Both compounds have CNS-research applicability that isn’t always obvious from their primary classifications (longevity for NAD⁺, metabolic for MOTS-c).

What’s the typical route of administration for these nootropic peptides?

Intranasal and subcutaneous are both published routes for Semax, Selank, and DSIP. Intranasal dominates Russian clinical-research applications (and is the format the registered Russian finished products use). Subcutaneous dominates Western mechanism-research applications. Adamax is published predominantly in SC and intranasal forms. NAD⁺ uses IV or SC because oral degradation is significant. MOTS-c uses SC.

Can these peptides be stacked together in research designs?

Yes, with the same caveats that apply to any multi-mechanism protocol. The most-published combinations: Semax + Selank for attention + anxiolysis dual-arm research; Semax + NAD⁺ for cognitive + cellular-energetics research; Selank + DSIP for anxiety + sleep-architecture research. Combinations should be designed around non-overlapping mechanism arms to maximise mechanistic insight per protocol.

What’s the storage protocol?

Standard peptide storage applies across the cluster: lyophilized vials at -20 °C long-term or 2-8 °C as working stock; reconstituted solution at 2-8 °C with use within ~30 days; protect from light; never freeze-thaw the reconstituted solution. Nasal-spray formulations of Semax and Selank in published research use a similar reconstitution profile with the addition of a nasal-spray vehicle.

Bottom line

The nootropic / CNS peptide cluster is the smallest of the seven peptide research families on the MedsBase catalogue but covers a coherent set of research scenarios. Semax is the reference compound for attention / cognitive-research protocols. Selank is the anxiolytic-mechanism comparator without benzodiazepine-class side effects. DSIP handles sleep-architecture research with slow-wave-specific applicability. Adamax is the frontier experimental arm. NAD⁺ and MOTS-c bridge cognitive research with cellular and mitochondrial energetics. For most nootropic-peptide research, the strategic pick reduces to: Semax as the cognitive arm, Selank as the anxiolytic arm, DSIP as the sleep arm, plus one energetics adjunct (NAD⁺ or MOTS-c) where the design calls for it.

Written by

Sophie Chen

Pharmaceutical Content Researcher · 8 years experience

Sophie Chen is a pharmaceutical content researcher with 8 years covering generic medication access and clinical pharmacology. She specialises in international regulatory frameworks, bioequivalence standards, and patient-facing education on therapeutic drug classes. She is not a clinician.