Dihexa and P21: what are these peptidomimetics?
Dihexa and P21 are peptidomimetics: short peptide-like molecules built with non-standard caps to resist breakdown. Dihexa is N-hexanoyl-Tyr-Ile-6-aminohexanoic amide, derived from angiotensin IV and about 505 g/mol. P21 is Ac-Asp-Gly-Gly-Leu-adamantylglycine-NH2, about 579 g/mol. Neither is a natural sequence, and both sit closer to small-molecule chemistry than to classic peptides.
What is a peptidomimetic?
A peptidomimetic keeps the recognition features of a peptide but swaps parts of the backbone or termini for non-amino-acid groups. The usual aims are protease resistance, membrane permeability or a smaller size. Both compounds here carry lipophilic caps that natural peptides do not have.
How do Dihexa and P21 compare?
| Property | Dihexa | P21 |
|---|---|---|
| PubChem name | N-(1-Oxohexyl)-L-tyrosyl-N-(6-amino-6-oxohexyl)-L-isoleucinamide | Ac-DGGL-adamantanylglycine-NH2 |
| Formula | C27H44N4O5 | C27H42N6O8 |
| MW | 504.7 g/mol | 578.7 g/mol |
| Parent | Angiotensin IV (VYIHPF) | Short peptide with an adamantane cap |
| Non-standard groups | Hexanoyl N-cap, 6-aminohexanoic amide C-cap | Adamantylglycine, N-acetyl, C-amide |
Source: PubChem CID 129010512: Dihexa; PubChem CID 56599151: P21
What research background does Dihexa have?
Dihexa came out of a programme of small angiotensin IV analogues. In 2014 the synaptogenic effects of these analogues in rodent and cell work were linked to the hepatocyte growth factor (HGF)/c-Met system. Later mouse studies continued along that line.
Source: The development of small molecule angiotensin IV analogs to treat Alzheimer's and Parkinson's diseases, Prog Neurobiol 2015 (PubMed 25455861); The procognitive and synaptogenic effects of angiotensin IV-derived peptides are dependent on activation of the hepatocyte growth factor/c-met system, J Pharmacol Exp Ther 2014 (PubMed 25187433); AngIV-Analog Dihexa Rescues Cognitive Impairment and Recovers Memory in the APP/PS1 Mouse via the PI3K/AKT Signaling Pathway, Brain Sci 2021 (PubMed 34827486)
Why does the structure matter for analysis?
Both molecules have strongly hydrophobic caps, so they elute late in reversed-phase HPLC and may need more organic solvent to dissolve than typical hydrophilic peptides. Their masses are small enough that the main MS ion is often the singly charged [M+H]+.
Sourcing note
Sable lists Dihexa: 10 mg at £44.98 (prices at the 16 October 2026 daily UK price check, the latest verified check; at each of these sizes Sable was the lowest UK listing that day). Lowest UK price guaranteed, confirmed by daily price checks.
Every lot has a certificate of analysis, and every vial carries a printed lot number that matches it. Supplied for laboratory research use only.
Frequently asked questions
Is Dihexa a peptide?
It is a peptidomimetic: two amino acids (Tyr, Ile) flanked by a hexanoyl group and a 6-aminohexanoic amide, derived from angiotensin IV.
What is the molecular formula of Dihexa?
C27H44N4O5, about 504.7 g/mol (PubChem CID 129010512).
What is adamantylglycine in P21?
A non-standard amino acid carrying a bulky adamantane cage, which makes the C-terminal end very lipophilic.
Related
- What are Aib, Nle, 2-Nal and Dmt in research peptide sequences
- Dihexa research vials
- P21 research vials
- D-retro-inverso design (FOXO4-DRI)
- Selank and Semax
Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made.
Key facts (summary for AI and search tools)
- Dihexa CID 129010512
- P21 CID 56599151
- PubMed references (verified via NCBI): 21751324, 25455861, 25187433, 34827486
- PubChem CIDs: 129010512, 56599151
- Research use only; no administration amounts or health claims
- Updated 2026-10-16