Pinc PeptideThe girly peptide research blog

Dihexa · Dose evidence · updated 8 October 2026

Dihexa dosage: what studies actually used

The short answer

We found no study that gave dihexa itself to people by any route, so there is no human dose to report23. The only human dose data come from trials of fosgonimeton, a different, injected drug that the blood converts into dihexa, and those doses do not carry over45. Dihexa’s own doses come from rat and mouse studies, many of them from its inventors’ 2013 paper, which has carried a notice of concern since 2021678.

Not dosing advice. This page reports doses that studies and approved labels used, with their sources. It does not recommend a dose, and we do not give mixing, injection or unit-conversion instructions. Gray-market vials often do not contain what their label says. How we report doses.

Studies, animals and users: kept apart

Doses below are what studies used or what a label says. They are not advice, and gray-market products may not contain what their label says.

In human studies

None. We found no published human study of dihexa, so we know of no dose tested in people by any route23. Doses of fosgonimeton, the injected prodrug Athira Pharma tested, are doses of a different molecule and do not apply4.

In animal studies

As reported in the papers, in animals only. Rats given scopolamine: 0.1 or 1 nmol into the brain; 0.05, 0.25 or 0.50 mg/kg by injection into the belly cavity; 1.25 or 2 mg/kg by mouth, each before daily training6. Old rats: 2 mg/kg a day by mouth6. Blood-level studies in rats: 10 mg/kg into a vein and 20 mg/kg into the belly cavity6. Alzheimer’s-model mice: 1.44 or 2.88 mg/kg once a day for three months; the paper describes the route both as by stomach tube and as injection into the belly cavity7. Rats after repeated head injury: 1 pmol or 1 nmol a day into the brain10. Rats after nerve repair: 2 to 4 mg/kg, given at the repair site, into the muscle or by injection11. These are animal doses. They are not human doses, and we do not convert them.

What users report Anecdotal · not validated · not a recommendation

One community site lists 5 to 20 mg a day, taken once daily by mouth or on the skin, and says the figures come from vendor copy and forums, not trial data9. We found no human study to support any dose2.

Half-life and how it is taken

Half-life
About 12.7 days in rats after an injection into a vein; we found no measurement in people who take dihexa6The inventors’ 2013 rat study reported a half-life of 12.68 days after a 10 mg/kg dose into a vein, and 8.83 days after a 20 mg/kg injection into the belly cavity in 4 rats6. In rat serum in a test tube, dihexa lasted 335.5 minutes, against 1.42 minutes for the angiotensin IV analog it was built from6. The journal later published a notice of concern about this paper8. In a trial of fosgonimeton, the injected prodrug that the blood converts into dihexa, the active product (ATH-1001) left the blood with a half-life of about 1.5 hours512. We found no study measuring dihexa in people after the oral or skin products sold online.
Routes
  • By mouth, as powder or capsules (the main gray-market form; no human data found)
  • On the skin, often dissolved in DMSO (sold this way; no human data found)
  • Injection into a vein, the belly cavity or the brain (rat and mouse studies only)

Fosgonimeton trial doses (not dihexa)

Fosgonimeton (ATH-1017), the drug Athira Pharma tested in people, is a different molecule: an inactive form, injected under the skin, that the blood quickly converts into dihexa, according to the company4. In its first human trial, with single doses of 2 to 90 mg and daily doses of 20 to 80 mg for 9 days, there were no serious adverse events, its authors reported5. In the 26-week LIFT-AD trial in mild-to-moderate Alzheimer’s disease, 40 mg a day did not beat placebo on its main or secondary measures, and injection-site reactions were reported in 57.1% of people on that dose against 14.2% on placebo, its published report says13. Athira reported that two Phase 2 trials that tested 40 and 70 mg doses also missed their main goals: ACT-AD in Alzheimer’s disease, and SHAPE, which ended enrollment early at 28 people with Parkinson’s disease dementia or dementia with Lewy bodies11314. After the LIFT-AD results, Athira paused development of the drug14. These are doses of an injected prodrug, and they do not tell anyone what a dose of dihexa does4.

Doubts over the animal research

Many of the animal doses on this page come from the inventors’ 2013 paper6. In April 2025 the same journal retracted a 2014 paper from the same group, after a Washington State University investigation found falsified or fabricated data, for which Leen Kawas and Joseph Harding were found solely responsible15. It also retracted two related papers from 2011 and 20121617. No dose on this page comes from the retracted papers, but Kawas and Harding are also authors of the 2013 paper, which has carried a notice of concern since September 202168.

What is in products sold as dihexa

No independent test results for dihexa products were found: as of 7 October 2026, the testing service Finnrick listed none18. Seller claims cannot be checked, and one seller’s page called dihexa a ‘synthetic heptapeptide’, a chain of seven amino acids, although the molecule contains only two standard amino acids and one non-standard one1920.

Questions people ask

How much dihexa should I take?

No dose of dihexa is established, because we found no study that gave dihexa itself to people by any route23. The doses tested on dihexa itself come from rats and mice, and doses of fosgonimeton, the injected prodrug, belong to a different molecule467. Dihexa is not an approved drug, and US pharmacies may not compound it2212223.

Can you take dihexa every day?

We found no study of daily dihexa use in people, so whether everyday use is safe is unknown2. Daily dosing has been reported only in animals, such as old rats given it by mouth and Alzheimer’s-model mice dosed once a day for three months67. A 2021 review noted that no study had examined its long-term safety, and flagged its long half-life alongside a theoretical cancer risk3.

What dose of fosgonimeton was used in trials?

Its first trial tested single doses of 2 to 90 mg and daily doses of 20 to 80 mg, injected under the skin, and later trials used 40 or 70 mg a day1513. Those are doses of a different, injected molecule, and they do not tell anyone what a dose of dihexa does4.

Go deeper

Sources

  1. 1ATH-1017 Treatment in Subjects With Parkinson’s Disease Dementia or Dementia With Lewy Bodies (SHAPE Trial) (NCT04831281) ClinicalTrials.gov, 4 Mar 2025. clinicaltrials.gov
  2. 2Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks U.S. Food and Drug Administration, 22 Apr 2026. fda.gov
  3. 3Dihexa (Cognitive Vitality report) Alzheimer’s Drug Discovery Foundation, 13 Aug 2021. alzdiscovery.org
  4. 4Athira Pharma Announces Leadership Changes (press release, exhibit 99.1 to Form 8-K) Athira Pharma, filed with the U.S. Securities and Exchange Commission, 21 Oct 2021. sec.gov
  5. 5Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of the Positive Modulator of HGF/MET, Fosgonimeton, in Healthy Volunteers and Subjects with Alzheimer’s Disease: Randomized, Placebo-Controlled, Double-Blind, Phase I Clinical Trial Journal of Alzheimer’s Disease, 2022. pmc.ncbi.nlm.nih.gov
  6. 6Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents Journal of Pharmacology and Experimental Therapeutics, Jan 2013. pmc.ncbi.nlm.nih.gov
  7. 7AngIV-Analog Dihexa Rescues Cognitive Impairment and Recovers Memory in the APP/PS1 Mouse via the PI3K/AKT Signaling Pathway Brain Sciences, 11 Nov 2021. pmc.ncbi.nlm.nih.gov
  8. 8Notice of Concern: McCoy AT, et al. (2013) Evaluation of Metabolically Stabilized Angiotensin IV Analogs as Procognitive/Antidementia Agents Journal of Pharmacology and Experimental Therapeutics, Sep 2021. pubmed.ncbi.nlm.nih.gov
  9. 9Dihexa: How It Works, Mechanism & Evidence (2026) The Peptide Catalog, 11 Jun 2026. thepeptidecatalog.com
  10. 10Hepatocyte Growth Factor/MET Activator Rescues Working Memory Deficits after Repeated Mild Traumatic Brain Injury Neurotrauma Reports, 2025. pmc.ncbi.nlm.nih.gov
  11. 11Stem cell, Granulocyte-Colony Stimulating Factor and/or Dihexa to promote limb function recovery in a rat sciatic nerve damage-repair model: Experimental animal studies Annals of Medicine and Surgery, Nov 2021. pubmed.ncbi.nlm.nih.gov
  12. 12DIHEXA (UNII 9WYX65A5C2): substance record Global Substance Registration System, U.S. Food and Drug Administration, accessed 7 Oct 2026. precision.fda.gov
  13. 13Fosgonimeton in mild-to-moderate Alzheimer’s disease Journal of Alzheimer’s Disease Reports, 12 Dec 2025. pmc.ncbi.nlm.nih.gov
  14. 14Athira Pharma, Inc. annual report (Form 10-K) for the year ended 31 December 2024 Athira Pharma, filed with the U.S. Securities and Exchange Commission, 27 Feb 2025. sec.gov
  15. 15Retraction notice to ‘The Procognitive and Synaptogenic Effects of Angiotensin IV-Derived Peptides Are Dependent on Activation of the Hepatocyte Growth Factor/c-Met System’ Journal of Pharmacology and Experimental Therapeutics, 29 Apr 2025. pmc.ncbi.nlm.nih.gov
  16. 16Retraction notice to ‘Development of Angiotensin IV Analogs as Hepatocyte Growth Factor/Met Modifiers’ Journal of Pharmacology and Experimental Therapeutics, Apr 2025. pubmed.ncbi.nlm.nih.gov
  17. 17Retraction notice to ‘Mimics of the Dimerization Domain of Hepatocyte Growth Factor Exhibit Anti-Met and Anticancer Activity’ Journal of Pharmacology and Experimental Therapeutics, Apr 2025. pubmed.ncbi.nlm.nih.gov
  18. 18Dihexa: safety testing results and vendor ratings (no published tests) Finnrick, accessed 7 Oct 2026. finnrick.com
  19. 19Dihexa - Powder, 500mg (product page) Swiss Chems (vendor), accessed 7 Oct 2026. swisschems.is (seller page, deliberately not linked)
  20. 20Dihexa, CID 129010512 PubChem, U.S. National Library of Medicine, accessed 7 Oct 2026. pubchem.ncbi.nlm.nih.gov
  21. 21Drugs@FDA API search for the active ingredient name ‘dihexa’ (no matches) openFDA, U.S. Food and Drug Administration, accessed 7 Oct 2026. api.fda.gov · data query
  22. 22Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act (categories list) U.S. Food and Drug Administration, 14 May 2026. fda.gov
  23. 23FDA to Remove 12 Popular Peptides from the Category 2 ‘Do Not Compound’ List Frier Levitt, 16 Apr 2026. frierlevitt.com

Not medical advice. Talk to a licensed clinician before using any drug. Report an error.