Skip to content

Dihexa vs P21

Updated 7 sources

Key differences

  1. 1Dihexa is an angiotensin IV analog said to work through HGF and c-Met; P21 is a CNTF fragment that raises BDNF in rodents.
  2. 2Dihexa doses are milligrams; P21 doses run from micrograms to low milligrams.
  3. 3Dihexa's two core mechanism papers were retracted in 2025, so its HGF story rests on withdrawn work.
  4. 4P21 is CNTF-derived and acts through BDNF in rodent work; Dihexa is an angiotensin IV analog said to boost HGF and its c-Met receptor.
  5. 5P21 doses run from micrograms to low milligrams; Dihexa doses are milligrams.
  6. 6P21's rodent papers carry no retractions; Dihexa's two core mechanism papers were retracted in 2025.

Side by side

Facts from each record, in the same words as their own pages.
Dihexa and P21 side by side
DihexaP21
Category
  • Cognitive
  • Cognitive
Evidence
  • Animal data only
  • Animal data only
FDA status
  • Not FDA approvedRegulatory
  • Not FDA approvedRegulatory
WADA
  • Prohibited
  • Not confirmed
Half-life
  • 12.68 days after IV dosing and about 8.8 days after IP dosing in rats, from a paper now under an expression of concernClinical study
  • About 1.5 hours in people for ATH-1001, the active metabolite of the related prodrug fosgonimeton; whether ATH-1001 is Dihexa is disputedClinical study
Not reported
Routes
  • Oral, Topical, Sublingual
  • Nasal, Subcutaneous injection
Forms
  • Capsule, Oral solution, Topical, Vial (powder), Nasal spray, Other form
  • Vial (powder), Nasal spray
Reported doses
  • 5 to 100 mg (oral)
  • 4 to 40 mg (topical)
  • 1 to 5% (topical)
  • 1 to 4 mg (nasal)
  • 500 to 1,000 mcg (nasal)
  • 100 to 1,000 mcg (subcutaneous injection)
Most cited frequency
  • Once daily
  • Once daily
Vial sizes
  • 10 mgCompetitor guide
  • 5 mg, 10 mg, 50 mg, 100 mgCompetitor guide
Mixed vial keeps
  • Mixed solution: refrigerate at 2 to 8 C and use within 14 days.Competitor guide
  • Refrigerate at 2 to 8 C and use within 28 to 30 days.Competitor guide
Protocols on file
  • 8
  • 10

Doses shown are what sources report, labelled by origin. Not medical advice.

Read each in full

Sources

7 sources, each checked by date. Record updated Oct 24, 2026. Numbers are restated in our own words and labelled by where they came from.

Competitor guide1

  1. P-21 dosage: what the community reportsthepeptidecatalog.com · checked Oct 24, 2026