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Peptides / Dihexa

Review scheduledAngiotensin IV analogueNot FDA approved

Dihexa

Dihexa is a small synthetic molecule derived from angiotensin IV, a fragment of a blood-pressure hormone. It was developed at Washington State University as a possible treatment for Alzheimer's disease and is now sold online as a nootropic, a product meant to boost thinking.

Main use
Memory and cognition
Committee review
Review by Feb 2027
Strongest evidence
Animals
Legal to compound in the US
Not yet

Effects studied or claimed

What it is promoted for, and where each effect has actually been seen

  • Better memory and learningAnimals
  • Growth of new connections between nerve cellsLab studies

How it is thought to work

It boosts signalling by HGF and its receptor c-Met, a pathway that helps nerve cells grow new connections.

What the evidence shows

In animals and the lab

Memory studies in rats, including models of Alzheimer's disease.

In people

None published. A drug from the same line of research, fosgonimeton, failed a large Alzheimer's trial in 2024.

Safety and unknowns

Unknown in humans. The HGF/c-Met pathway it boosts also helps some cancers grow and spread.

FDA review

Scheduled for review by the FDA's compounding advisory committee before the end of February 2027.

Committee votes are advice to the FDA. A peptide can only be compounded legally once the FDA adds it to the 503A bulks list through formal rulemaking, which has no fixed deadline.

Sources

Analysis

A potent brain compound with a cautionary family history

Peptide Evidence IndexBiology 4/10In people 0.5/10Index 1.4, rank 14 of 15See the full index

Dihexa was developed at Washington State University from angiotensin IV, a fragment of a blood pressure hormone. It acts on the HGF and c-Met system, which helps nerve cells grow new connections. A university announcement in 2012 claimed it was about seven orders of magnitude more potent than BDNF at building those connections, a line still used in online marketing.

In rats with drug-induced memory problems, and in older rats, oral Dihexa improved performance in a water maze test (McCoy and colleagues, 2013). The research led to a company, Athira Pharma, which developed a related compound, fosgonimeton, for Alzheimer's disease. In 2024 its larger trial failed to beat placebo on the main measure of cognition and function. Dihexa itself has never been tested in people.

Our view. the rodent results are interesting, but the closest human test of the same idea did not work. Because the HGF and c-Met pathway also drives growth in some cancers, taking an untested, highly potent activator carries risks that have not been studied.

Studies and reports cited

  1. McCoy AT et al. Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents. J Pharmacol Exp Ther, 2013
  2. 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

Summary of published research for general information. It is not medical advice and not a recommendation to use this substance.

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General information, not medical advice. Do not buy or inject unregulated peptides.