Side by side
Dihexa vs P21
Both are discussed for cognition & mood. What this site records about each, side by side. Every figure is on the compound's own page with the source it came from.
| Dihexa | P21 | |
|---|---|---|
| What it is | A small peptide reported as vastly more potent than BDNF at forming new synapses in animals. No human has been studied on it, and the potency is the concern, not the selling point. | A tetrapeptide derived from a nerve growth factor, engineered to reach the brain. Real academic research, entirely in mice. |
| EvidenceHow much human evidence exists, not how well it works. | Preclinical | Preclinical |
| Regulatory statusReviewed 2026-08-16 | Not approved anywhere, and never studied in a published human trial. Developed in academic research with an associated patent; no clinical development programme has reported results. Sold only as a research chemical. | Not approved anywhere and never studied in a human trial. Developed in academic research with associated patents; no clinical programme has reported. Sold only as a research chemical. |
| Routes | Oral, Topical | Subcutaneous, Nasal |
| Cheapest per mgVials only, read from vendors' own listings and dated on the price index. | $0.32/mg | $1.40/mg |
| Median per mg | $6.08/mg | $12.32/mg |
| Vendors with a price | 6 | 10 |
| Storage once mixed | In a carrier solution, refrigerated and used within weeks. Stability in DMSO or similar carriers has not been characterised. | Refrigerated at 2–8 °C. Nasal solutions are handled more than injectables and are correspondingly easier to contaminate. |
Compare two other compounds · The full price index
This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on BioAlmanac is medical advice. Nothing here ranks these two against each other. A table can show that one has more human evidence behind it or costs less per milligram; neither of those is a recommendation, and the right comparison for any person is one their doctor makes with them.