At a glance

What is dihexa?

Dihexa is a synthetic peptide derived from angiotensin IV, designed to be taken orally and cross into the brain. It was developed in academic research as a candidate for cognitive disorders and is sold through "research chemical" channels for brain function and memory. It is not an approved medicine.

How does it work?

Dihexa has been proposed to promote the formation of new connections between nerve cells by enhancing a growth-factor pathway in the brain (hepatocyte growth factor and its receptor, c-Met). An important caveat belongs here: the primary research paper describing this mechanism has since been retracted, which weakens even the preclinical rationale. The remaining supporting data are from cell and rodent experiments. This describes a proposed mechanism, separate from any demonstrated benefit in people.

Is it FDA-approved?

No. Dihexa is not approved by the FDA or by any regulator. It is not on FDA compounding lists and was not among the peptides reviewed at the 2026 FDA compounding advisory meetings.

What does the research show?

The evidence is preclinical, and partly compromised. Animal experiments (such as maze-based memory tests¹) have been reported, but the foundational mechanism paper has been retracted², and there are no completed human efficacy trials. There is no sound human evidence that dihexa improves cognition.

Frequently asked questions

Is dihexa FDA-approved?

No. As of September 2026, dihexa is not FDA-approved for any human indication. It is not eligible for 503A compounding: FDA removed it from Category 2⁴ in April 2026, but it is not on the 503A bulks list or in Category 1. There is no legal prescription pathway for dihexa in the United States.

Is dihexa legal in the United States?

Dihexa is not FDA-approved and is not approved for human use. It is distributed through gray-market channels under "research use only" labeling, which does not confer legality for human consumption. The precise legal status as a consumer product involves regulatory nuances best addressed by a qualified regulatory attorney. Superpower does not offer legal or regulatory guidance on obtaining gray-market research chemicals.

Can a doctor prescribe dihexa?

No licensed provider can prescribe dihexa under 503A compounding law because it is not on the FDA's 503A bulks list or in Category 1. It cannot be compounded by a licensed pharmacy for a patient-specific prescription. Any provider offering to prescribe it is doing so outside established legal and regulatory frameworks.

What is the '10 million times more potent than BDNF' claim based on?

The comparison does not appear in the two main published dihexa papers. Those studies report that dihexa induced new synapses at picomolar concentrations⁵ in rat hippocampal neurons, and the paper tying that effect to HGF/c-Met has since been retracted. Higher potency at one narrow in vitro endpoint would not predict clinical cognitive efficacy in humans. BDNF's pharmacology, receptor interactions, and signaling pleiotropy make a simple molar comparison uninformative as a guide to real-world cognitive effects.

Was a key dihexa paper retracted?

Yes, two papers. A 2012 paper, which originally framed dihexa-class molecules as HGF-dimerization mimetics, was formally retracted in April 2025⁶ following a 2021 expression of concern. A 2014 paper in the same journal, which proposed that angiotensin IV-derived peptides produce their procognitive and synaptogenic effects via HGF/c-Met activation, was also retracted in April 2025⁷ after a 2021 expression of concern. The 2013 paper reporting oral cognitive restoration in rats carries a 2021 expression of concern⁸ but has not been formally retracted. The combined effect is that both the foundational biochemical characterization of dihexa and its primary mechanistic framing through HGF/c-Met have been called into question in the published record.

Is dihexa safe?

No human safety data exist for dihexa as of September 2026, and no human exposure data⁴ on dihexa products have been identified. No human Phase 1 dose-escalation study, pharmacokinetic profile, or systematic adverse-event characterization has been published. The compound's proposed c-Met agonist mechanism raises a specific theoretical oncogenic concern, because c-Met signaling is linked to tumor proliferation, invasion, and metastasis⁹ in several cancer types. This is not a minor caveat. It is a major safety unknown for a compound being circulated in consumer nootropic markets with no clinical oversight.

Is there human evidence for dihexa?

No. All published cognition data for dihexa comes from rodent models. No human efficacy or safety trial has been completed, and no trial is registered on ClinicalTrials.gov¹⁰ as of September 2026. The preclinical signal has been partially replicated by an independent laboratory in mice¹¹; whether any of it translates to humans is unknown.

What is the difference between dihexa and other nootropic peptides?

Dihexa is structurally a small peptidomimetic derived from angiotensin IV, with proposed oral bioavailability and blood-brain barrier penetration in rodents, properties that distinguish it from most injectable research peptides. Its proposed mechanism through the HGF/c-Met receptor system is distinct from peptides acting on growth hormone secretagogue receptors, BDNF pathways, or acetylcholine systems. Its most notable distinguishing feature in the current literature is the combination of preclinical cognitive signal, retracted foundational biochemistry paper, zero human data, and a theoretical oncogenic concern that remains uncharacterized.

More for brain & sleep