Dihexa

The corpus-integrity story is the central fact about Dihexa in 2026, and the page treats it that way. The jpet-2025-dihexa-retraction-landscape entry catalogs the chronology in detail; this page summarizes its implications for any reader weighing use. Briefly: the September 2021 Expression of Concern on McCoy et al. 2013 — the foundational Dihexa design-and-characterization paper — was the early signal. In April 2025, two further Wright/Harding lab papers were formally retracted by the Journal of Pharmacology and Experimental Therapeutics on separate image-integrity grounds: Benoist et al. 2014 (the principal HGF/c-Met dependence paper that supplied the modern mechanistic framing) and Kawas et al. 2012 (the AngIV-analog chemistry-and-pharmacology companion). The McCoy 2013 Expression of Concern has not been upgraded to a retraction as of May 2026 but sits on the same research-integrity track.

The clinical lineage unraveled in the same window. Athira Pharma was founded on the Wright/Harding research program, with original Harding-lab postdoc Leen Kawas as CEO; Athira developed fosgonimeton (ATH-1017), a distinct compound optimized from the Dihexa research program as a positive modulator of HGF/MET signaling. Kawas was forced to take leave from Athira after Washington State's investigation into figure-data alterations in the underlying academic work. Fosgonimeton advanced through the Phase I trial documented in Hua et al. 2022 and into a Phase II/III Alzheimer's-disease program. The pivotal LIFT-AD trial in mild-to-moderate Alzheimer's disease failed its primary endpoint in 2025, and Athira paused further fosgonimeton development. The academic-research-integrity layer and the clinical-program-outcome layer of the Dihexa lineage have unraveled in the same year.

The biohacker and nootropic case for Dihexa rests almost entirely on the same Wright/Harding-lab corpus that has unraveled. The honest framing is not "controversial but interesting": it is that the foundational papers carry an Expression of Concern, two closely related papers from the same lab have been retracted, the most-directly-relevant clinical-development descendant has just failed its definitive efficacy trial, and the most-cited marketing claim — "10 million times more potent than BDNF" — originates specifically from the Expression-of-Concern paper and refers narrowly to a cell-culture synapse-counting endpoint that does not translate to human cognitive potency. Dihexa has no published human trials of any kind. There is no independently funded replication of the original cognitive-restoration findings by a separately synthesized batch of compound, and the retractions have made that absence acutely visible.

Dihexa is the clearest case in this corpus of a peptide whose marketing narrative substantially outpaced its replicable evidence base. The right framing is integrity-and-failure, not "promising but unproven" — the foundational mechanism papers are under serious research-integrity pressure, the closest clinical descendant failed in 2025, and the central potency headline originates from the paper carrying the Expression of Concern. The direct teardown of the "10 million times more potent than BDNF" claim walks the methodology in detail. Anyone considering use is operating on a substantially thinner evidence base than the public peptide-vendor literature implies.