For laboratory and research use only. Not for human consumption.

NNZ-2591 Alternatives

Explore peptides similar to NNZ-2591. Compare mechanisms, effects, and find the best alternative for your research.

Original

NNZ-2591

Cognitive

View Profile →

NNZ-2591 is Neuren Pharmaceuticals' second drug, a synthetic analog of cyclic glycine-proline (cGP), a small ring-shaped molecule the body makes when it breaks down IGF-1. It is taken by mouth and is being developed for rare childhood neurodevelopmental disorders: Phelan-McDermid syndrome is furthest along, with the first-ever phase 3 trial in that disease started in late 2025, and Angelman and Pitt Hopkins syndromes behind it. Phase 2 results looked encouraging, but they were small open-label studies, so nobody knows yet whether it truly works.

Similar Peptides

Semax

Cognitive

Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) developed in Russia in the 1980s as an analog of the ACTH(4-10) fragment, with a Pro-Gly-Pro tail added to resist breakdown. It is researched and used as a neuroprotective and nootropic agent, typically intranasally, and keeps the cognitive and neurotrophic effects of the ACTH fragment without the parent hormone's cortisol-raising activity. It is used clinically and registered in Russia (including for ischemic stroke and cognitive disorders) but is not approved by the FDA or EMA, and Western evidence is limited.

Trofinetide

Cognitive

FDA

Trofinetide is a synthetic version of a tiny three-amino-acid fragment (glycine-proline-glutamate) that the body clips off IGF-1. It is the first drug ever approved for Rett syndrome: the FDA approved it as Daybue in March 2023 for patients 2 years and older, Health Canada followed in October 2024, and the EU authorised it as Daybu in August 2026 after first refusing it. It is a real, approved medicine with a real but modest effect, and the trade-off is blunt: most patients get diarrhea, and a meaningful share stop because of it.

GB-115

Cognitive

GB-115 is a synthetic dipeptide anxiolytic developed in Russia, chemically the amide of N-phenylhexanoyl-glycyl-L-tryptophan and described as a retro-analogue of cholecystokinin-4. Rather than acting like a benzodiazepine, it blocks cholecystokinin receptors, a different anti-anxiety route. It has been studied in animals and in a small pilot human study, but it is not an approved or widely available medication.

ARA-290

Cognitive

ARA-290 (cibinetide) is a synthetic 11-amino-acid peptide carved from the tissue-protective region of erythropoietin (EPO), engineered to calm inflammation and repair nerves without thickening the blood the way EPO does. It has been tested in real Phase 2 human trials, mainly for sarcoidosis-related small fiber neuropathy and diabetic neuropathy, and holds FDA orphan drug status, but it was never approved and development largely stalled. So: genuine clinical data, promising signals, no finish line.

Davunetide

Cognitive

Davunetide (NAP) is an eight-amino-acid fragment (NAPVSIPQ) of activity-dependent neuroprotective protein (ADNP), discovered at Tel Aviv University and given as a nasal spray. It was meant to protect brain cells by stabilizing microtubules, the scaffolding that tau normally supports. Its big test, a phase 2/3 trial in progressive supranuclear palsy (PSP), failed cleanly in 2012, and development stalled. It has since been revived by its inventors, who argue it works in women and are pursuing ADNP syndrome, but those claims rest on reanalyses of old data, not a new successful trial.

Selank

Cognitive

Selank is a synthetic seven-amino-acid peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) built from the natural immune peptide tuftsin, with a small chemical tweak to make it last longer in the body. It was developed in Russia as an anti-anxiety and nootropic agent and is approved there for generalized anxiety disorder, but it has no FDA or EMA approval and almost no Western clinical data. The pitch is calm and focus without the sedation, dependence, or withdrawal that come with benzodiazepines.

All Cognitive Peptides

Selank

Selank is a synthetic seven-amino-acid peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) built from the natural immune peptide tuftsin, with a small chemical tweak to make it last longer in the body. It was developed in Russia as an anti-anxiety and nootropic agent and is approved there for generalized anxiety disorder, but it has no FDA or EMA approval and almost no Western clinical data. The pitch is calm and focus without the sedation, dependence, or withdrawal that come with benzodiazepines.

Semax

Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) developed in Russia in the 1980s as an analog of the ACTH(4-10) fragment, with a Pro-Gly-Pro tail added to resist breakdown. It is researched and used as a neuroprotective and nootropic agent, typically intranasally, and keeps the cognitive and neurotrophic effects of the ACTH fragment without the parent hormone's cortisol-raising activity. It is used clinically and registered in Russia (including for ischemic stroke and cognitive disorders) but is not approved by the FDA or EMA, and Western evidence is limited.

Cerebrolysin

Cerebrolysin is not a single peptide but a mixture: a preparation of small peptides and free amino acids made by enzymatically breaking down purified porcine (pig) brain protein, manufactured by EVER Neuro Pharma in Austria. It is given by injection and is approved as a prescription drug in dozens of countries for stroke, traumatic brain injury, and dementia, but it is not FDA-approved in the United States. Despite decades of use abroad, the human evidence remains genuinely contested.

Dihexa

Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a small synthetic peptide built from angiotensin IV, engineered at Washington State University to be orally active and to cross into the brain. The pitch is bold: it is studied as a procognitive compound that may rebuild synaptic connections, and lab claims of extreme potency made it a darling of the nootropic underground. The reality check: every supporting study is in cells or rodents, there are zero human clinical trials, and in April 2025 the journal retracted two of the key papers behind its proposed mechanism (2012 and 2014) after a university investigation.

P21

P21 (also written P021) is a small synthetic peptide reverse-engineered from the most active region of ciliary neurotrophic factor (CNTF), with an adamantane group bolted on to help it survive in the body and reach the brain. It is studied as a neurogenic and neurotrophic compound for Alzheimer's disease and other memory disorders, with the appeal of getting CNTF-like benefits in a small, orally available molecule. The honest status: it looks genuinely promising in mouse models, but the entire evidence base comes from a single research group and there are no human trials.

GB-115

GB-115 is a synthetic dipeptide anxiolytic developed in Russia, chemically the amide of N-phenylhexanoyl-glycyl-L-tryptophan and described as a retro-analogue of cholecystokinin-4. Rather than acting like a benzodiazepine, it blocks cholecystokinin receptors, a different anti-anxiety route. It has been studied in animals and in a small pilot human study, but it is not an approved or widely available medication.

ARA-290

ARA-290 (cibinetide) is a synthetic 11-amino-acid peptide carved from the tissue-protective region of erythropoietin (EPO), engineered to calm inflammation and repair nerves without thickening the blood the way EPO does. It has been tested in real Phase 2 human trials, mainly for sarcoidosis-related small fiber neuropathy and diabetic neuropathy, and holds FDA orphan drug status, but it was never approved and development largely stalled. So: genuine clinical data, promising signals, no finish line.

Normoftal

Normoftal is an obscure Russian eye supplement from the Khavinson 'peptide bioregulator' tradition, sold as short peptides meant to support the retina. Be clear-eyed about this one: it is marketed as a dietary supplement, not an approved drug, and the evidence behind it is thin and comes almost entirely from one research lineage. We keep the claims minimal on purpose.

Quick Comparison

PeptideCategoryFDA StatusAction
NNZ-2591CognitiveNot ApprovedOriginal
SemaxCognitiveNot ApprovedCompare →
TrofinetideCognitive✓ ApprovedCompare →
GB-115CognitiveNot ApprovedCompare →
ARA-290CognitiveNot ApprovedCompare →