Dihexa
Not FDA-approved
Also known as: ATH-1001, PNB-0408, N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide
Dihexa is a small lab-made molecule built around two amino acids, tyrosine and isoleucine, with chemical groups added at each end. It was proposed to help nerve cells form new connections and so improve memory. The 2014 paper explaining its mechanism was retracted in April 2025 after a Washington State University investigation found falsified and/or fabricated data in its figures.
How it works
- It was proposed to switch on HGF/c-Met, a growth-factor signal that helps nerve cells grow new connections (synapses).
- The main study behind that idea, done in rats and lab-grown cells, has been retracted, so the mechanism is unconfirmed.
- Fosgonimeton, a form with a phosphate group added, is converted back into dihexa in the blood. It was developed to test the approach in people.
Evidence
Alzheimer's disease (given as fosgonimeton)
In a randomized trial of 287 people with mild-to-moderate Alzheimer's disease, it did not improve memory tests or daily functioning compared with placebo.
Memory and learning (other uses)
Rat studies reported memory effects. The 2014 study proposing how it works was retracted, and no other use has been tested in people.
Caveats
- The 2014 paper explaining how dihexa works was retracted in April 2025. The retraction followed a Washington State University investigation that found falsified and/or fabricated data in its figures.
- The 2013 rat study that first described dihexa has not been retracted, but the journal issued an expression of concern about it in 2021.
- Dihexa has not been studied in people except as fosgonimeton, which the body turns into dihexa. In those trials it was cleared within hours and did not improve memory or daily functioning. Its long-term safety is unknown.
- In the Alzheimer's trial, serious side effects were no more common than with placebo, but more people stopped because of side effects, mostly injection-site reactions.
- When overactive, c-Met, the signal dihexa was proposed to activate, helps several cancers grow and spread. Stimulating it carries a theoretical cancer risk.
References
- Benoist CC, et al. J Pharmacol Exp Ther. 2014;351:390-402 (retracted).
- Benoist CC, et al. Retraction notice. J Pharmacol Exp Ther. 2025;392:103567.
- McCoy AT, et al. J Pharmacol Exp Ther. 2013;344:141-154.
- Hua X, et al. J Alzheimers Dis. 2022;86:1399-1413.
- Porsteinsson AP, et al. J Alzheimers Dis Rep. 2025;9:25424823251405817 (LIFT-AD).
This page is for education only. It is not medical advice. Decisions about any treatment belong with a physician who knows your history.