What are nootropic peptides?
"Nootropic peptides" is a search label, not a scientific or regulatory class. It covers short synthetic peptides and peptide-derived compounds studied in brain and nerve-cell models, and searches for cognitive peptides research or brain peptides research lead to the same short list.
Strictly, a neuropeptide is a peptide that neurons release as a signal; most compounds sold as neuropeptides for research are synthetic, modified fragments of hormones, immune peptides or growth factors. Their parent molecules, reported pathways and evidence differ widely, and most of the data come from cell and animal models. Disguised Alpha supplies several of these compounds for laboratory research use only. Nothing on this page is guidance for use in people.
Where each compound comes from
These compounds share no core structure. Most are built from a different parent molecule, and each came out of one laboratory or institute. Structures are from PubChem.
- Semax (CID 9811102): Met-Glu-His-Phe-Pro-Gly-Pro, residues 4 to 7 of adrenocorticotropic hormone (ACTH) joined to a Pro-Gly-Pro tail. Moscow researchers describe it as an ACTH(4-10) analog (Dolotov et al., 2006).
- Selank (CID 11765600): Thr-Lys-Pro-Arg-Pro-Gly-Pro, the immune peptide tuftsin with the same tail (Renke and Chinellato, 2026).
- Dihexa (CID 129010512): N-hexanoic-Tyr-Ile-(6) aminohexanoic amide. A Washington State University group built it from Nle-Tyr-Ile, the core of the angiotensin IV analog Nle¹-angiotensin IV, modifying both ends for metabolic stability and barrier permeability (McCoy et al., 2013).
- P21, also written P021 (CID 56599151): Ac-Asp-Gly-Gly-Leu joined to an adamantylated glycine. Its New York developers describe it as a small-molecule peptide mimetic of ciliary neurotrophic factor (CNTF) (Kazim and Iqbal, 2016).
- Pinealon (CID 10273502): the tripeptide Glu-Asp-Arg, one of the short peptides from the St Petersburg program covered in our peptide bioregulators explainer.
Per the product pages, Semax, Selank, P21 and Pinealon are lyophilized powders stored at -20°C, and Dihexa and Noopept are capsules kept at 15 to 25°C. Dihexa and P21 carry groups that are not amino acids, so compare identity data with the published molecular formula rather than a mass calculated from an amino acid sequence; our COA explainer covers identity tests.
Nootropic peptides at a glance
Summaries of the cell, animal and human studies cited here and in each guide.
| Compound | Parent molecule | Reported pathway | Evidence level | Our guide |
|---|---|---|---|---|
| Semax | ACTH(4-7), plus Pro-Gly-Pro | BDNF and TrkB expression in rat hippocampus | Rodent and cell studies; Russian clinical reports; approved drug in Russia | Semax guide |
| Selank | Tuftsin, plus Pro-Gly-Pro | GABAergic gene expression in rat cortex | Rodent and cell studies; Russian clinical reports; approved drug in Russia | Selank guide |
| Dihexa | Angiotensin IV (Nle¹-angiotensin IV core) | HGF/c-Met, proposed in a paper retracted in 2025 | Rodent, zebrafish and cell studies; no human trials | Dihexa guide |
| P21 (P021) | Ciliary neurotrophic factor fragment | LIF signaling block and BDNF expression (proposed) | Mouse, rat and cell studies, mostly from its developers; no human studies | P21 guide |
| Pinealon | None; a short peptide designed in the bioregulator program | DNA binding (proposed) | Cell and rodent studies, mostly from one institute; small Russian reports in people | Pinealon guide |
| Noopept | Dipeptide derivative designed as a piracetam analog | Converted to cycloprolylglycine (rat data); NGF and BDNF mRNA | Rodent and cell studies; small Russian clinical studies | Noopept guide |
| Adamax (DW 1032) | Not published; public descriptions point to Semax | None on record | No published studies | Adamax guide |
How the reported mechanisms differ
No shared target links these compounds, and most mechanism work comes from the laboratories that developed each one.
BDNF and TrkB: Semax, P21 and Noopept
In rat hippocampus, one application of Semax raised BDNF protein up to 1.4-fold and phosphorylation of its receptor TrkB 1.6-fold, with 3-fold more exon III BDNF mRNA (Dolotov et al., 2006).
P21's developers propose that it inhibits leukemia inhibitory factor (LIF) signaling and raises BDNF expression, and that the added BDNF lowers GSK-3β activity and tau hyperphosphorylation (Kazim and Iqbal, 2016), but in Cdkl5 knockout mice chronic P21 did not raise brain BDNF (Mottolese et al., 2024). For Noopept, rat hippocampus showed more NGF and BDNF mRNA after a single exposure and after 28 days, while cortical levels fell after a single exposure (Ostrovskaya et al., 2008).
HGF and c-Met: Dihexa and the 2025 retractions
Dihexa's developers proposed that it acts through hepatocyte growth factor (HGF) and its receptor c-Met. Their 2014 paper reported that Dihexa binds HGF with high affinity and promotes c-Met phosphorylation, and that an HGF antagonist blocked its effect in the water maze (Benoist et al., 2014). The journal issued an expression of concern in 2021 and retracted the paper in 2025 (retraction notice, 2025).
A 2012 paper from the group describing the 6-AH family of angiotensin IV analogs as blockers of HGF dimerization was retracted at the same time (Kawas et al., 2012), and the 2013 paper that introduced Dihexa carries a 2021 expression of concern (McCoy et al., 2013). Later papers still describe Dihexa as an HGF/c-Met modulator, but the retracted work is not evidence.
GABAergic findings: Selank
In rat frontal cortex, Selank or GABA changed the expression of 45 of 84 neurotransmission genes at 1 hour and 22 at 3 hours, with positively correlated changes at 1 hour, which the authors read as consistent with allosteric modulation of the GABAergic system (Volkova et al., 2016).
DNA binding: Pinealon
Pinealon is proposed to act inside the cell rather than at a receptor. Fluorescein-labeled Pinealon entered the nucleus of HeLa cells, and in binding tests the peptide quenched the fluorescence of labeled oligonucleotides in a sequence-dependent way, favoring CNG- and CAG-containing sequences (Fedoreyeva et al., 2011). No receptor has been reported, and the model comes mainly from one research program.
What the human evidence shows
Human data come almost entirely from Russian centers. In a study of 110 people in rehabilitation after ischemic stroke, subgroups given Semax had higher plasma BDNF throughout follow-up and faster recovery on the Barthel index of daily activities; the abstract describes no randomization or placebo group (Gusev et al., 2018).
A randomized comparison in 62 people with generalized anxiety disorder or neurasthenia found similar changes on anxiety rating scales with Selank and the benzodiazepine medazepam (Zozulia et al., 2008). Noopept has only small Russian studies and no randomized, placebo-controlled trial in PubMed, and the few Russian-language reports on Pinealon in people also tested the related peptide vesugen. PubMed indexes no study of Dihexa, P21 or Adamax in people (all searched October 2026).
Regulatory status
Semax and Selank are approved as drugs in Russia; a 2026 review lists stroke and neurological disease for Semax and mild anxiety for Selank, and states that neither is approved elsewhere (Renke and Chinellato, 2026). Drugs@FDA lists no product containing Semax, Selank, Dihexa, P21, Pinealon or omberacetam, the nonproprietary name of Noopept (openFDA search, October 2026), and FDA warning letters in 2019 and 2022 called Noopept products sold with Alzheimer's disease claims unapproved new drugs.
None of these names appears on the World Anti-Doping Agency's 2026 Prohibited List, whose S0 class covers pharmacological substances not addressed elsewhere on the List and with no current government approval for human therapeutic use. Disguised Alpha's materials are research chemicals, not those Russian medicines, and are not for human consumption.
Compounds often grouped with nootropic peptides
Noopept: a dipeptide derivative
Noopept (omberacetam, GVS-111), N-phenylacetyl-L-prolylglycine ethyl ester (PubChem CID 180496, 318.4 g/mol), has one Pro-Gly peptide bond plus a phenylacetyl cap and an ethyl ester: a dipeptide derivative its Moscow developers designed as a piracetam analog, not a peptide in the usual sense. One hour after rats received it, the parent compound was undetectable in brain while cycloprolylglycine had risen 2.5-fold, so they proposed that it acts as a prodrug (Gudasheva et al., 1997).
Adamax: a product name without a published structure
Adamax is sold under the code DW 1032. Our product pages give no sequence or formula, PubChem has no compound record and PubMed holds no study under either name; public descriptions present it as a Semax derivative but disagree on the structure. Our Adamax guide sets out what is on record.
Key sources
- Dolotov OV, 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. DOI 10.1016/j.brainres.2006.07.108.
- Volkova A, et al. "Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission." Front Pharmacol. 2016. PMID 26924987. DOI 10.3389/fphar.2016.00031.
- McCoy AT, et al. "Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents." J Pharmacol Exp Ther. 2013. PMID 23055539. DOI 10.1124/jpet.112.199497. Expression of concern, 2021.
- Benoist CC, et al. "The procognitive and synaptogenic effects of angiotensin IV-derived peptides are dependent on activation of the hepatocyte growth factor/c-met system." J Pharmacol Exp Ther. 2014. PMID 25187433. DOI 10.1124/jpet.114.218735. Retracted by the journal in 2025; listed because it is widely cited, not as evidence.
Frequently asked questions
What are nootropic peptides?
A search label for short synthetic peptides and peptide-derived compounds studied in brain and nerve-cell models, such as Semax, Selank, Dihexa, P21 and Pinealon. It is not a scientific or regulatory class.
What is the difference between Semax and Selank?
Semax starts from ACTH(4-7) and Selank from tuftsin; both end in Pro-Gly-Pro. Semax is studied mainly for BDNF and TrkB signaling (Dolotov et al., 2006), Selank for GABAergic gene expression (Volkova et al., 2016). See our Semax vs Selank comparison.
Are nootropic peptides linked to BDNF?
Some are. Semax raised BDNF protein in rat hippocampus, P21's developers link it to BDNF expression, and Noopept raised hippocampal BDNF mRNA in rats. Dihexa's proposed target is HGF/c-Met instead, and Selank's findings center on GABAergic genes.
Was the Dihexa research retracted?
The key mechanism paper was. The 2014 paper reporting that Dihexa acts through HGF and c-Met was retracted in 2025 (Benoist et al., 2014), a related 2012 paper was retracted at the same time, and the 2013 paper that introduced Dihexa carries a 2021 expression of concern.
Are nootropic peptides FDA approved?
No. Drugs@FDA lists no product containing Semax, Selank, Dihexa, P21, Pinealon or omberacetam (Noopept) (openFDA search, October 2026). Semax and Selank are approved drugs in Russia (Renke and Chinellato, 2026).
Is Noopept a peptide?
Not in the usual sense. It is a dipeptide derivative, N-phenylacetyl-L-prolylglycine ethyl ester, that rat studies suggest is converted to cycloprolylglycine (Gudasheva et al., 1997).
Where can researchers buy these compounds?
Disguised Alpha lists Semax, Selank, the Semax & Selank blend, P21, Pinealon and Adamax as lyophilized vials, Dihexa and Noopept as capsules, and an Adamax Aerosol Spray, for laboratory research, with lot certificates on each product page and in the COA portal.
Related guides
- Semax research guide
- Selank research guide
- Semax vs Selank: research comparison
- Dihexa research guide
- P21 research guide
- Adamax research guide
- Pinealon research guide
- Noopept research guide
- NSI-189 research guide
- Peptide bioregulators explained
- What is a COA?
- COA portal: published certificates, by lot
- Research hub
Disguised Alpha products are for research use only. They have not been evaluated for safety or effectiveness in humans. Not for human consumption. All products are intended for laboratory research purposes only.