Peptides / Brain and mood

Synthetic analog · 2 amino acids · 194.2 Da

NNZ-2591

NNZ-2591 is an experimental cyclic dipeptide analog studied for neurodevelopmental disorders such as Phelan-McDermid syndrome, in phase 3 trials and not approved. Animal studies tested it mostly on brain damage, motor function and memory. PepBank shows 23 results on NNZ-2591 from animal and lab studies. No study in people has reported results yet. Data as of 2026-10-30.

Also known as Ercanetide, NNZ 2591, NNZ2591, cyclo-L-glycyl-L-2-allylproline

2 amino acids, from first to lastGX

Evidence level: Animal and lab studies onlyNo study in people has results. ClinicalTrials.gov lists 7 trials.

Results in people

0% of 23 results

Results in animals

100% of 23 results

Results in lab cells

0% of 23 results

From computer models

0% of 23 results

Overview

NNZ-2591 at a glance

What it is	Synthetic analog, 2 amino acids
Approval	Regulatory status not recorded
In sport	Status unknown
Studies	3 studies with results. All of them gave NNZ-2591, with 23 results. 23 in animals
Clinical trials	7 registered: 2 active or planned, 2 with posted results

The science

What is NNZ-2591?

A cyclic dipeptide analog studied in neurodevelopmental disorders.

Amino acids in one chain

The history of NNZ-2591

2007
The oldest paper on NNZ-2591 in PepBank is from 2007.
2020May
A registered trial of NNZ-2591 started (NCT04379869).

NNZ-2591 structure and chemistry

The key facts about the molecule. Long codes are in the closed section below.

Sequence, 2 amino acidsFrom the first amino acid to the last

G1X

Darker means more water-repelling+ and − show charge in the bodyOutlined: changed amino acid

Structure

NNZ-2591 is a synthetic analog of 2 amino acids, with a ring, 2 changed amino acids.

Formula

C₁₀H₁₄N₂O₂

Molecular weight

194.2 g/mol

CAS number

847952-38-9

Development

Neuren Pharmaceuticals. Highest phase: phase 3.

Identifiers

PubChem 11735696, ChEMBL CHEMBL4802144, UNII 2T1HU6069S, DrugBank DB15601, KEGG D13364

Full sequence, SMILES and InChIKey

InChIKey
WVKCGUOWPZAROG-JTQLQIEISA-N

SMILES
C=CC[C@@]12CCCN1C(=O)CNC2=O

See charge, composition and 3D structure on the Scientific page

The evidence

What NNZ-2591 studies show

Results grouped by what the studies measured. Each card shows where its results come from.

Animal and lab studies onlyNo study in people has results. ClinicalTrials.gov lists 7 trials.

Brain and nerves

8 results · 8 animal

In rats with hypoxic-ischemic injury, central NNZ‑2591 reduced lateral cortical brain damage. Neuropharmacology, 2007

Top results

In rats with hypoxic-ischemic injury, central NNZ‑2591 reduced lateral cortical brain damage. (Neuropharmacology, 2007)
In rats with striatal lesions, NNZ‑2591 increased doublecortin-positive neuroblast expression versus saline. (British journal of pharmacology, 2009)
In rats with hypoxic-ischemic injury, central NNZ‑2591 reduced hippocampal brain damage. (Neuropharmacology, 2007)

Daily life and fitness

3 results · 3 animal

In rats with hypoxic-ischemic injury, subcutaneous NNZ‑2591 improved sensory and motor function. Neuropharmacology, 2007

Top results

In rats with hypoxic-ischemic injury, subcutaneous NNZ‑2591 improved sensory and motor function. (Neuropharmacology, 2007)
In rats with striatal lesions, early NNZ‑2591 treatment reduced motor deficit versus saline. (British journal of pharmacology, 2009)
In rats with striatal lesions, delayed NNZ‑2591 improved motor function from week 7 onwards versus saline. (British journal of pharmacology, 2009)

Memory and thinking

2 results · 2 animal

In scopolamine-treated rats, NNZ‑2591 did not reverse the learning and memory deficit versus water. Behavioural brain research, 2010

Top results

In scopolamine-treated rats, NNZ‑2591 did not reverse the learning and memory deficit versus water. (Behavioural brain research, 2010)
In scopolamine-treated rats, NNZ‑2591 improved memory retention versus water. (Behavioural brain research, 2010)

Immune system and inflammation

1 result · 1 animal

In rats with hypoxic-ischemic injury, NNZ‑2591 reduced microglial activation. Neuropharmacology, 2007

Top results

In rats with hypoxic-ischemic injury, NNZ‑2591 reduced microglial activation. (Neuropharmacology, 2007)

All 3 NNZ-2591 studies by area Open the Scientific page

Key NNZ-2591 studies

Studies in people come first, then studies in animals and in the lab.

Animals
Peripheral administration of a novel diketopiperazine, NNZ 2591, prevents brain injury and improves somatosensory-motor function following hypoxia-ischemia in adult rats
Guan et al. 2007 · Neuropharmacology · cited by 38
13 results
Animals
NNZ-2591, a novel diketopiperazine, prevented scopolamine-induced acute memory impairment in the adult rat
Guan et al. 2010 · Behavioural brain research · cited by 21
5 results
Animals
A novel diketopiperazine improves functional recovery given after the onset of 6-OHDA-induced motor deficit in rats
Krishnamurthi et al. 2009 · British journal of pharmacology · cited by 10
5 results

All 3 NNZ-2591 studies

NNZ-2591 clinical trials

ClinicalTrials.gov lists 7 trials of NNZ-2591. 2 are active or planned, and 2 have posted results. PepBank does not show trial results.

Solid bars are dates that happened. Hatched bars are planned dates. Data from ClinicalTrials.gov.

An Open-label Study of NNZ-2591 in Pediatric Participants With Phelan-McDermid Syndrome

Phase 3recruiting180 planned

A Study of NNZ-2591 in Pediatric Participants With Phelan-McDermid Syndrome

Phase 3recruiting160 planned

An Open-Label Study of Oral NNZ-2591 in Pitt Hopkins Syndrome (PTHS-001)

Phase 2completed28 people

All 2 NNZ-2591 trials

Status and safety

Is NNZ-2591 approved?

FDA

United States

Status unknown

Status unknown.

EMA

European Union

Status unknown

Status unknown.

WADA

Sport

Not recorded

Status unknown.

Regulatory status not recorded. Status unknown.

Laws and labels change, so check the regulator for the current status.

NNZ-2591 side effects and safety

PepBank has no safety result from studies of NNZ-2591 yet. That does not mean NNZ-2591 is safe.

Doses studied (3 shown)

The doses that these studies used. They are not recommendations.

Dose as reported	Class	Species	Route	Duration	Design	Source
30 mg/kg	Animal	rats	oral gavage	Not reported	Study in live animals	Guan 2010
20 ng.day(-1)	Animal	rats	intracerebroventricular	3 days	Study in live animals	Krishnamurthi 2009
0.2, 1 and 5 mg.day(-1)	Animal	rats	subcutaneous	14 days	Study in live animals	Krishnamurthi 2009

Questions and more

Ask a question about NNZ-2591

The answer links to every study it uses.

What does the evidence say about NNZ-2591?Is NNZ-2591 tested in people?Compare with Trofinetide Compare with Davunetide

Sources

Database: PepBank data for NNZ-2591 (data version 308560)
Regulator: FDA status record
Regulator: EMA status record
Regulator: WADA status record
Trial registry: ClinicalTrials.gov

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

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NNZ-2591

Also known as Ercanetide, NNZ 2591, NNZ2591, cyclo-L-glycyl-L-2-allylproline

What it is

Synthetic analog, 2 amino acids

Approval

Regulatory status not recorded

In sport

Status unknown

Studies

3 studies with results. All of them gave NNZ-2591, with 23 results.
23 in animals

Clinical trials

7 registered: 2 active or planned, 2 with posted results

Dose as reported

Class

Species

Route

Duration

Design

Source

30 mg/kg

Animal

rats

oral gavage

Not reported

Study in live animals

Guan 2010

20 ng.day(-1)

Animal

rats

intracerebroventricular

3 days

Study in live animals

Krishnamurthi 2009

0.2, 1 and 5 mg.day(-1)

Animal

rats

subcutaneous

14 days

Study in live animals

Krishnamurthi 2009

NNZ-2591

NNZ-2591 at a glance