PEPTIDEREPORT

Angiotensin IV analog / hepatocyte growth factor activator (cognitive enhancement)

Dihexa

Dihexa (N-hexanoic-tyr-ile-(6) aminohexanoic amide) is a metabolically stabilized analog of angiotensin IV developed by researchers at Washington State University, including Joseph W. Harding and Jay W. Wright. It was designed to activate the hepatocyte growth factor (HGF)/c-Met receptor system, which is implicated in synaptogenesis and cognitive function. Dihexa has been studied only in animal models (rats and mice); no human clinical trials have been published. It is not FDA-approved for any indication and is sold as a 'research chemical' or supplement despite lacking any clinical safety or efficacy data in humans.

Research watch — preclinical only Last reviewed 2026-07-01 Next review 2026-07-29

Evidence snapshot

Track preclinical literature only. Do not publish dosing, sourcing, or treatment instructions. Flag the widely-circulated '10 million times stronger than BDNF' claim as an exaggeration from a single rat study. Emphasize that no human clinical data exists.

Dihexa was developed at Washington State University (Harding, Wright et al.) as an angiotensin IV analog targeting the HGF/c-Met pathway. The key pharmacological characterization was published in JPET in 2013 (PMID 23055539, DOI 10.1124/jpet.112.199497).

A 2014 study in Journal of Pharmacology and Experimental Therapeutics found that the procognitive and synaptogenic effects of angiotensin IV-derived peptides (including Dihexa) are dependent on activation of the hepatocyte growth factor/c-Met system (PMID 25455861, DOI 10.1124/jpet.114.218735).

A 2021 study in Brain Sciences found that Dihexa rescued cognitive impairment and recovered memory in APP/PS1 Alzheimer's model mice via the PI3K/AKT signaling pathway (PMID 34827486, DOI 10.3390/brainsci11111487).

No human clinical trials have been published. The widely-repeated claim that Dihexa is '10 million times stronger than BDNF' is an extrapolation from a single preclinical rat study (McCoy et al., 2013) and has not been validated in any human trial.

Tracked claims

Dihexa is '10 million times stronger than BDNF' for cognitive enhancement.

Evidence level: Community discussion — exaggerated from preclinical

Sources: PubMed / NCBI, PubMed / NCBI

This claim is a sensationalized extrapolation from a single 2013 rat study by McCoy et al. (PMID 23055539) which compared Dihexa's synaptogenic effects to BDNF in an in vitro dendritic spine model. The '10 million times' figure refers to relative potency in a specific assay, not clinical efficacy. No human data supports any cognitive enhancement claim.

Dihexa rescues cognitive impairment in Alzheimer's disease mouse models.

Evidence level: Peer reviewed — preclinical (animal)

Sources: PubMed / NCBI, PubMed / NCBI

The 2021 Brain Sciences study (PMID 34827486) demonstrated cognitive rescue in APP/PS1 transgenic mice. The 2024 Journal of Huntington's Disease study (PMID 38489193) showed effects in a 3-nitropropionic acid rat model of Huntington's disease. Both are preclinical only with no human replication.

Dihexa's cognitive effects are mediated through the HGF/c-Met receptor system.

Evidence level: Peer reviewed — preclinical

Sources: PubMed / NCBI, PubMed / NCBI

The 2014 JPET study (PMID 25455861) established that Dihexa's procognitive and synaptogenic effects depend on HGF/c-Met activation. The 2015 review by Wright et al. (PMID 25649658, DOI 10.1016/j.pneurobio.2014.11.004) in Progress in Neurobiology describes the development of angiotensin IV analogs for Alzheimer's and Parkinson's. The mechanism is well-characterized in animals but untested in humans.

Sources on this page

Source records are stored in the repo and linked from each claim.

Related compounds

Noopept

Noopept (N-phenylacetyl-L-prolylglycine ethyl ester) is a dipeptide nootropic compound developed in Russia and registere...

Research watch — registered in Russia, sold as supplement in US

Selank

Selank is a synthetic heptapeptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences i...

Research watch — preclinical and limited Russian clinical use