Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| Dihexa | P21 (Cerebrolysin Analog) | |
|---|---|---|
| Category | Peptides | Peptides |
| Standard Dose | Research indicates 10-20 mg daily via oral or sublingual administration. | Research indicates 750 mcg-1 mg daily via intranasal administration or subcutaneous injection. |
| Timing | Morning dosing preferred. Can be taken with or without food (orally active). | Morning dosing preferred for cognitive effects. |
| Cycle Duration | 2-4 week cycles with equal rest periods. Long-term safety data is extremely limited. | 4-8 week cycles with 4-week rest periods. |
| Evidence Level | animal_plus_anecdotal | animal_plus_anecdotal |
Dihexa (N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide) is an orally active, blood-brain barrier-permeable oligopeptide derived from angiotensin IV. It binds hepatocyte growth factor (HGF) with high affinity, inhibiting HGF dimerization and synergistically promoting c-Met receptor phosphorylation and signaling. Activation of HGF/c-Met drives procognitive effects through increased dendritic arborization, spinogenesis, and synaptogenesis via the PI3K/AKT signaling pathway. Research indicates it is approximately 10 million times more potent than BDNF for new synapse formation.
Research indicates 10-20 mg daily via oral or sublingual administration.
Morning dosing preferred. Can be taken with or without food (orally active).
2-4 week cycles with equal rest periods. Long-term safety data is extremely limited.
P21 is a tetrapeptide (DGGL — Asp-Gly-Gly-Leu) derived from the most active region of ciliary neurotrophic factor (CNTF, residues 148-151), identified through reverse engineering of Cerebrolysin. An adamantylated glycine enhances BBB permeability and metabolic stability. P21 works through LIF/STAT3 pathway inhibition, BDNF/TrkB/CREB signaling enhancement, and restoration of synaptic proteins (synaptophysin, synapsin I) and glutamate receptors. It promotes neurogenesis and maturation of newborn neurons in the dentate gyrus.
Research indicates 750 mcg-1 mg daily via intranasal administration or subcutaneous injection.
Morning dosing preferred for cognitive effects.
4-8 week cycles with 4-week rest periods.
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