Dihexa

Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a lab-made molecule built from two amino acids, tyrosine and isoleucine, with chemical groups added so the body breaks it down more slowly (“metabolically stabilized”). It was derived from analogs of angiotensin IV (AngIV) and was tested in rat models of dementia. The FDA lists it as dihexa acetate, a salt form.

No published human trial exists. The FDA says it has not identified any human exposure data for dihexa acetate by any route. A ClinicalTrials.gov search on October 16, 2026 found no registered trial, and a 2026 review of neuroactive peptides, including dihexa, selank and semax, notes “a current lack of clinical trials.” Claims about memory in people are therefore extrapolated from rat studies.

In April 2025 the Journal of Pharmacology and Experimental Therapeutics retracted two papers from the research group behind dihexa: a 2014 paper that proposed dihexa works by activating the HGF/c-Met system, and a 2012 paper on angiotensin IV analogs as HGF/Met modifiers. The notice says a Washington State University investigation found figures and data that were “falsified and/or fabricated,” and that two authors “were found to be solely responsible.” The 2013 rat study is not retracted but carries an expression of concern from 2021. The mechanism most often quoted for dihexa rests on retracted data.

No. Dihexa is not approved for any use in the US. Dihexa acetate had been nominated for pharmacy compounding and sat on the FDA’s Category 2 list of substances that may present significant safety risks; in April 2026 the FDA moved it to the list of withdrawn nominations, which is not an approval. The FDA plans to discuss dihexa acetate with its Pharmacy Compounding Advisory Committee at a meeting “before the end of February 2027,” with no date set.

Nobody knows, because it has not been studied in people. The FDA has no human exposure data for dihexa acetate by any route and says it lacks information on whether it would cause harm in humans. No study has measured how dihexa is absorbed, how long it lasts or what it does to the body in people. A product with no reported side effects is not the same as a product shown to be safe.

No official label exists, so no source sets a water volume or describes the form dihexa is sold in. If you have a powder vial, the arithmetic is the same as for any peptide: the water only sets the concentration (mg in the vial ÷ mL of water = mg per mL), and the reconstitution calculator does it for your vial. That math says nothing about whether dihexa is safe to inject: the FDA has no human exposure data for it by any route. Talk to a licensed prescriber or pharmacist before using any unapproved product.