Dihexa vs Selank
A neutral, side-by-side comparison of two nootropic & cognitive peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Dihexa
Dihexa is a synthetic hexapeptide derived from angiotensin IV, developed at Washington State University. It is considered one of the most potent nootropic peptides known — in rodent models it outperforms BDNF itself for synaptogenesis and cognitive enhancement, acting through the hepatocyte growth factor (HGF) / c-Met receptor system. Unlike most nootropics, Dihexa is highly lipophilic and can be administered transdermally or orally.
Full profileSelank
Selank is a synthetic heptapeptide derived from tuftsin, an endogenous immunomodulatory peptide. Developed in Russia by the Institute of Molecular Genetics, it has been studied extensively for anxiolytic, nootropic, and immunomodulatory effects. It is registered as a medication in Russia and Ukraine.
Full profile| Dihexa | Selank | |
|---|---|---|
| Category | Nootropic & Cognitive | Nootropic & Cognitive |
| Also known as | PNB-0408, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide | TP-7, Tuftsin analog |
| Evidence | Preclinical only | Research-stage |
| Dosing range | 10mg–20mg mg, Once daily (or every other day — long-lasting effects) | 250mcg–1000mcg mcg, 1–2x daily |
| Administration | Oral (capsule), Transdermal (cream/lotion — lipophilicity makes this effective), Subcutaneous injection (less common) | Intranasal (most common — direct CNS delivery), Subcutaneous injection |
| Key side effects | Potential for pro-proliferative effects — HGF/c-Met pathway promotes cell growth (theoretical cancer concern at high doses), Headache (uncommon), Mental fatigue if overdosed, Long half-life means effects accumulate — take every other day initially | Mild sedation at high doses, Nasal irritation (intranasal route), Generally very well-tolerated, No reported dependence or withdrawal |
| Cited sources | 2 references | 1 reference |
Key differences
- Evidence level differs: Dihexa is preclinical only, while Selank is research-stage.
- Administration: Dihexa — Oral (capsule), Transdermal (cream/lotion — lipophilicity makes this effective), Subcutaneous injection (less common); Selank — Intranasal (most common — direct CNS delivery), Subcutaneous injection.
- Dosing units differ: Dihexa is dosed in mg, Selank in mcg — they operate at different scales.
- Frequency: Dihexa is typically Once daily (or every other day — long-lasting effects); Selank is 1–2x daily.
- Research depth: this profile cites 2 sources for Dihexa vs 1 for Selank.
How each works
Dihexa
Dihexa (PNB-0408) was developed by Joseph Harding and colleagues at WSU as a metabolically stable angiotensin IV analog. It binds hepatocyte growth factor (HGF), potentiating its interaction with the c-Met receptor — a pathway critical for dendritic branching, synapse formation, and synaptic plasticity. In rodent Alzheimer's and scopolamine-impaired models, Dihexa restored cognitive performance at doses ~7 orders of magnitude lower than BDNF. It readily crosses the blood-brain barrier due to its lipophilicity, unlike BDNF itself.
Selank
Selank modulates GABA-A receptors and influences BDNF expression, producing anxiolytic effects comparable to benzodiazepines without sedation or dependence. Russian clinical studies report improvements in generalized anxiety disorder, cognitive performance, and mood stability. It also appears to modulate T-helper cell ratios and interferon production.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.