Dihexa
Oral Dihexa reversed an induced water-maze deficit in the high rat group (PMID 23055539; p < 0.001; funders: Lainge, Washington I-171, NIH MH086032, Hope; checked 24 Aug 2026). That group did not differ from controls (PMID 23055539; p > 0.05; same funders and date). In old rats, the drug improved the learning curve (PMID 23055539; p < 0.03; same funders and date). The named searches found no direct human trial result.
What substance and names does Dihexa identify?
Dihexa is a synthetic angiotensin IV analogue. The paper names it N-hexanoic-Tyr-Ile-(6) aminohexanoic amide (PMID 23055539; checked 24 Aug 2026).
The American FDA/NCATS GSRS also lists PNB-0408 and ATH-1001 (GSRS; checked 24 Aug 2026). GSRS assigns UNII 9WYX65A5C2 (GSRS; checked 24 Aug 2026). It assigns CAS 1401708-83-5 (GSRS; checked 24 Aug 2026).
GSRS links Fosgonimeton as a prodrug of Dihexa. This page does not transfer trials of that prodrug to direct Dihexa findings.
What did the rat and cell study measure?
| Model | Measured finding | Primary source | Funders | Checked |
|---|---|---|---|---|
| Scopolamine-impaired rats, 8-10 per group | High oral group fully reversed the water-maze deficit; p < 0.001; no difference from vehicle control, p > 0.05 | PMID 23055539 | Lainge Endowment; Washington I-171; NIH MH086032; Hope Foundation | 24 Aug 2026 |
| Probe trial, 8-10 rats per group | High group spent more time in the target quadrant than impaired controls; p < 0.001 | PMID 23055539 | Same four funders | 24 Aug 2026 |
| Aged rats, 6 per group | Oral group had a different learning curve from untreated rats; p < 0.03 | PMID 23055539 | Same four funders | 24 Aug 2026 |
| Cultured rat hippocampal neurons, 200 dendritic segments | Mean spine count was 41 versus 15 per 50 micrometres with vehicle; p < 0.001 | PMID 23055539 | Same four funders | 24 Aug 2026 |
| Second neuron experiment, 60 dendritic segments | Mean spine count was 23.9 versus 17.4 with vehicle; p < 0.0001 | PMID 23055539 | Same four funders | 24 Aug 2026 |
The paper studied rats and rat cells. It did not test people.
The paper states that J.W. Wright and J.W. Harding founded and held shares in M3 Biotechnology. It says the company was making drugs from this work.
What safety or adverse findings did that paper report?
The paper did not test toxicity. It did not print a full table of harms. It measured maze scores, chemical traits, dendritic spines, and synapses.
The rat and cell findings do not show human safety.
Is there a direct human Dihexa trial result?
No direct result was found. A PubMed filter for Dihexa clinical trials found zero records on 24 Aug 2026. The named ClinicalTrials.gov search found zero studies on the same date.
Fosgonimeton is a separate prodrug. Its trials are not trials of a vial labelled Dihexa.
What does evidence tier C mean here?
The direct findings come from rats and cells. The entry assigns tier C (checked 24 Aug 2026). No direct human trial result is linked.
What is the recorded EU status?
The European Commission active-substance index has no entry for Dihexa, PNB-0408, or ATH-1001 (Union Register index; checked 24 Aug 2026).
The index covers central EU approvals. It does not settle national lists. The EU field remains unclear.
What does the September 2024 first-observed date mean?
A market study logged 159 samples from January 2020 through September 2024 (PMID 40558871; checked 24 Aug 2026). Its table has one Dihexa sample. The sample was sold as a dietary supplement and called a research chemical.
The paper does not give the Dihexa sample's month. The register uses 2024-09 as a by-date from the stated window end. It is not the sample's exact date.
The paper reports no outside funding. One author worked for the Austrian health and food-safety agency. The other authors reported no business or financial ties.
What does this register entry cover?
This entry covers the drug and its names. It keeps prodrug findings apart. It has no test result for a reader's vial. No full guide is installed yet.