Dihexa vs Noopept
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 profileNoopept
Dipeptide-derived nootropic developed in Russia and used across Eastern Europe as a cognitive enhancer and neuroprotective agent. Structurally related to piracetam but estimated to be approximately 1000× more potent by weight. Rapidly crosses the blood-brain barrier and is hydrolyzed to the endogenous neuropeptide cycloprolylglycine, which is proposed as its primary active metabolite.
Full profile| Dihexa | Noopept | |
|---|---|---|
| Category | Nootropic & Cognitive | Nootropic & Cognitive |
| Also known as | PNB-0408, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide | GVS-111, N-phenylacetyl-L-prolylglycine ethyl ester, omberacetam, N-Phenylacetyl-L-Prolylglycine Ethyl Ester |
| Evidence | Preclinical only | Research-stage |
| Dosing range | 10mg–20mg mg, Once daily (or every other day — long-lasting effects) | 5mg–20mg mg, 1–3x daily oral or sublingual (8–12 week cycles) |
| Administration | Oral (capsule), Transdermal (cream/lotion — lipophilicity makes this effective), Subcutaneous injection (less common) | Oral (capsule/powder), Sublingual (dissolved under tongue), Intranasal |
| 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 | Headache (especially without choline supplementation), Irritability, Brain fog at high doses, Insomnia (if taken too late in day) |
| Cited sources | 2 references | 2 references |
Key differences
- Evidence level differs: Dihexa is preclinical only, while Noopept is research-stage.
- Administration: Dihexa — Oral (capsule), Transdermal (cream/lotion — lipophilicity makes this effective), Subcutaneous injection (less common); Noopept — Oral (capsule/powder), Sublingual (dissolved under tongue), Intranasal.
- Frequency: Dihexa is typically Once daily (or every other day — long-lasting effects); Noopept is 1–3x daily oral or sublingual (8–12 week cycles).
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.
Noopept
Noopept (GVS-111) enhances AMPA-receptor function and increases expression of BDNF and NGF in the hippocampus and basal forebrain. Its active metabolite cycloprolylglycine acts as an endogenous neuropeptide with anxiolytic and cognition-enhancing properties. Russian clinical trials demonstrate cognitive improvement in subjects with cognitive impairment, with a better tolerability profile than piracetam at equipotent doses.
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.