Dihexa

• Cognitive enhancement (rodent)
• Neuroplasticity
• Memory-formation research

Unlike typical nootropics that briefly nudge brain chemistry, Dihexa is designed to physically rewire the brain. It activates the HGF/c-Met pathway, a growth-and-repair system the body normally uses to respond to injury, and in doing so drives synaptogenesis, the formation of new synapses, along with the branching of neurons. The idea is structural rather than chemical: instead of a transient boost in neurotransmitters, it aims to build lasting new connections between brain cells. It is small, crosses into the brain easily, and works when taken orally.

1. Step 1HGF/c-MetDihexa switches on a growth and repair pathway the body normally uses after injury.
2. Step 2New synapsesIn rodents that signal builds new connections between brain cells and branches neurons.
3. Step 3Oral and brain entryIt is small enough to cross into the brain and it works taken by mouth.

Synthetic oligopeptide derived from angiotensin IV.

Type

Angiotensin-IV-derived oligopeptide

Acts on

HGF/c-Met pathway

Effect

Synaptogenesis

Route

Oral, brain-penetrant

Human trials

None

Approved

No

• Oral

  research suspension Dihexa suspended in isotonic saline for gavage. The patent does not establish a human oral product or storage stability. Rat memory experiments described in a patent.

• Research

  dry research powder and laboratory solution Dry-stock Dihexa dissolved in DMSO for rat pharmacokinetic experiments. The patent says dry stock was stored at minus 20 C. This is a laboratory stock condition, not finished-vial, reconstitution, or consumer storage stability. Rat intravenous and intraperitoneal pharmacokinetic experiments.

• Injection

  Recorded because this entry documents injectable use. The Atlas holds no vial, reconstitution or storage detail for it.

Dihexa is a potent, untested neuro compound with an oncogenic-pathway concern, which makes it especially inappropriate for developing brains. There is no pediatric data and no rationale for cognitive-enhancement use in minors. Any cognitive concern in a child belongs with specialists, not a gray-market research compound; there is no appropriate pediatric use.

Dihexa originated in Joseph Harding's laboratory at Washington State University as a metabolically stabilized analog in the angiotensin-IV / Norleual series, coded PNB-0408, and its cognition data rest entirely on that lab's rodent and in-vitro work from about 2011 to 2015. Commercialization moved to M3 Biotechnology, later renamed Athira Pharma, which did not advance dihexa itself but instead developed a phosphate prodrug, fosgonimeton (ATH-1017, converting in plasma to the active metabolite ATH-1001), to reach clinical trials. Fosgonimeton progressed through the ACT-AD Phase 2 and LIFT-AD Phase 2/3 Alzheimer's studies, the latter missing its endpoints in September 2024, while dihexa in its raw form continues to circulate through unregulated research-chemical vendors sold as not for human consumption.

Dihexa emerged from Joseph Harding’s work at Washington State University on angiotensin IV analogs, selected as the most promising for its brain penetration and oral activity. A 2013 finding that it built synapses with roughly seven orders of magnitude more potency than BDNF became its signature claim, supported by striking reversals of Alzheimer’s-like deficits in rodents. The broader HGF approach drew pharmaceutical investment through a related drug, but in 2021 the foundational potency study received an expression of concern over image integrity, and the related Alzheimer’s drug later failed in human trials. Through it all, Dihexa spread as a gray-market nootropic on the strength of its preclinical legend.

• Whether the extraordinary preclinical potency translates to any human benefit, which no trial has tested.
• What the cancer risk is of activating the HGF/c-Met pathway in people.
• Whether the clouded foundational potency data holds up under scrutiny.
• What a safe human dose would even be, given no safety profile exists.

Human trialsWhether Dihexa itself ever enters genuine clinical testing remains the key question.HGF/c-Met approachDampened by the related drug’s human-trial failure.Integrity resolutionWhether the clouded foundational data is upheld or retracted matters for its credibility.Persistent gray marketOngoing nootropic use despite the absence of human evidence.

Dihexa is not FDA-approved and has no completed human trials; it is an investigational research compound. It is sold gray-market as an oral or injectable nootropic, which is not an approved use. It is not a classic anti-doping substance, but its unapproved, untested status should give anyone pause.

Status current as of July 2026. Regulatory positions change, sometimes quickly.

Potency

7 orders > BDNF (rodent)

Target

HGF / dendritic spines

Human trials

Zero

Source

Unregulated only

What follows is unfinished work on our side, not a finding about Dihexa.

Nothing outstanding on this one.