Cortexin vs Dihexa
Bovine cerebral cortex-derived polypeptide preparation with nootropic, neuroprotective, and antioxidant properties used clinically in Russia for cerebrovascular disorders, cognitive impairment, and pediatric neurology
Angiotensin IV-derived oligopeptide that potentiates hepatocyte growth factor to drive synaptogenesis and cognitive enhancement with extraordinary potency
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Cortexin
10–10 mg
Dihexa
8–20 mg
Frequency
Cortexin
Once daily
Dihexa
Once daily
Administration
Cortexin
Intramuscular (IM) injection
Dihexa
Oral (capsule/tablet)
Cycle length
Cortexin
8-12 weeks
Dihexa
4-6 weeks
Onset speed
Cortexin
Moderate (1-2 weeks)
Dihexa
Moderate (1-2 weeks)
Evidence level
Cortexin
Limited human trials
Dihexa
Preclinical only — animal and cell-culture studies; no human trials
Benefit ratings
Brain Recovery
Cognitive Function
Neuroprotection
Cognitive
Healing & Recovery
Anti-Aging
Compound specifications
Cortexin
Molecular formula
Complex mixture — no single molecular formula (contains multiple low molecular weight polypeptide fractions, L-amino acids, vitamins, and trace elements)
Molecular weight
Low molecular weight water-soluble polypeptide fractions — specific molecular weight distribution varies as a complex biological mixture
Half-life
Approximately 2-6 hours (varies by route of administration)
Bioavailability
~85-100% (intramuscular injection)
CAS number
Not assigned (biological mixture)
Dihexa
Molecular formula
C27H44N4O5
Molecular weight
504.7 g/mol
Half-life
~12 days (following IV administration in rats)
Bioavailability
Orally active and blood-brain barrier permeable — specific oral bioavailability percentage not published
CAS number
1401708-83-5
Dosing compared
Cortexin
Intramuscular
10 mg
Once daily · 10 days per course; repeat in 3-6 months if needed
The standard adult dose per the manufacturer instructions. The 10 mg vial is dissolved in 1-2 mL of saline, water for injection, or 0.5% procaine and injected into a muscle. Children under 20 kg get 0.5 mg/kg. [6]
Dihexa
Oral
5–8 mg
Once daily · 2–4 weeks
Lower starting amount reported in practice. Dihexa has no human clinical trials, so all amounts come from animal research and community use [2][4].
8–20 mg
Once daily · 4–6 weeks
Commonly reported daily range in practice for cognitive support [2][4].
20–45 mg
Once daily · 4–6 weeks, then reassess
Upper end of amounts reported in practice. No long-term human safety data exists, so this should be approached with caution [2][4].
Sublingual
5–15 mg
Once daily · 4–6 weeks
Held under the tongue as an alternative to swallowing; amounts reported in practice are similar to oral use [4].
Topical
5–15 mg in DMSO carrier
Once daily · 4–6 weeks
Applied to the skin in a DMSO solution to help absorption; used in practice as a non-oral option [4].
Best suited for
Cortexin
Cognitive support in chronic cerebral ischemia and cerebrovascular disease
Cortexin is particularly well-suited for individuals focused on cognitive support in chronic cerebral ischemia and cerebrovascular disease. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [5].
Neuroprotection and neurorecovery following stroke or traumatic brain injury
Cortexin is particularly well-suited for individuals focused on neuroprotection and neurorecovery following stroke or traumatic brain injury. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [7].
Pediatric neurology including cerebral palsy and developmental delays
Cortexin is particularly well-suited for individuals focused on pediatric neurology including cerebral palsy and developmental delays. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [7][8].
Adjunctive treatment in epilepsy management
Cortexin is particularly well-suited for individuals focused on adjunctive treatment in epilepsy management. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [7][8].
Dihexa
Age-Related Cognitive Decline
Dihexa directly addresses the synaptic loss that underlies age-related cognitive decline by building new functional synaptic connections in the hippocampus. Animal studies demonstrate restored spatial learning in aged rats, [6] making it a compelling candidate for combating memory loss associated with aging.
Neuroplasticity Enhancement
Unlike nootropics that work through neurotransmitter modulation, dihexa drives physical neuroplasticity — the formation of new dendritic spines and synapses. [6] This makes it ideal for individuals looking to enhance their brain's capacity for learning and adaptation at a structural level.
Neurodegenerative Disease Research
Preclinical evidence in APP/PS1 Alzheimer's mice and scopolamine-induced amnesia models [4][6] positions dihexa as a leading research compound for neurodegenerative disease. It is patented for potential use in Alzheimer's and Parkinson's diseases, with ongoing interest from the research community.
Advanced Nootropic Stacking
Dihexa's unique mechanism (HGF/c-Met potentiation) is complementary to most other nootropic mechanisms, making it an excellent addition to advanced cognitive enhancement protocols when combined with choline donors, racetams, or adaptogens.
Side effects
Cortexin
Common
- Injection site reactions
- Headache
- Dizziness
- Nausea
- Agitation or restlessness
- Transient blood pressure changes
Uncommon
- Allergic reactions
Serious
- Severe allergic reaction / Anaphylaxis
Dihexa
Common
- Headache
- Vivid dreams or altered sleep patterns
- Emotional sensitivity
- Mild fatigue during adjustment
Uncommon
- Gastrointestinal discomfort
Serious
- Theoretical oncogenic risk from c-Met activation
Safety & evidence
Cortexin
Evidence level
Limited human trials
FDA status
Research compound
Safety overview
Cortexin is a porcine brain-derived polypeptide preparation used in Russian neurology that is not FDA-approved and has no Western rigorous safety data. As an undefined mixture of peptides and proteins extracted from animal brains, batch standardization and quality control are not guaranteed. Concerns include potential transmissible spongiform encephalopathy (TSE/prion) risk from animal CNS tissue, although documented cases have not been reported. Allergic reactions to porcine proteins are possible. No formal human safety assessments, toxicology studies, or clinical trials by modern regulatory standards have been conducted. Use in Western countries is essentially non-existent due to regulatory limitations on animal-derived neurological products.
Contraindications
- Known hypersensitivity to Cortexin or any component including glycine stabilizer
- Allergy to bovine-derived biological products
- Pregnancy — insufficient safety data for use during pregnancy
- Breastfeeding — insufficient data on excretion into breast milk
Dihexa
Evidence level
Preclinical only — animal and cell-culture studies; no human trials
FDA status
Research compound
Safety overview
Dihexa has demonstrated a favorable safety profile in published animal studies, with no reported tumorigenic effects or organ toxicity at cognitive-enhancing doses. However, the compound has not undergone formal human clinical trials, and long-term safety data does not exist. [7] The primary theoretical safety concern is sustained activation of the HGF/c-Met proto-oncogenic pathway, which could theoretically promote tumor initiation or growth. [7] The extremely long half-life (~12 days) [6][7] raises additional concerns about compound accumulation with chronic daily dosing. Anecdotal reports from the nootropics community generally describe good tolerability at doses of 5-20 mg daily, with headaches and vivid dreams as the most commonly reported effects.
Contraindications
- Known or suspected malignancy — c-Met/HGF pathway activation may promote tumor growth
- Pregnancy and breastfeeding — no safety data available
- History of cancer, particularly HGF/c-Met-driven tumors (hepatocellular, gastric, lung)
- Severe hepatic impairment
Which is right for you?
Choose Cortexin if...
- Cognitive support in chronic cerebral ischemia and cerebrovascular disease
- Neuroprotection and neurorecovery following stroke or traumatic brain injury
- Pediatric neurology including cerebral palsy and developmental delays
- Adjunctive treatment in epilepsy management
Choose Dihexa if...
- Cognitive enhancement and memory consolidation in age-related decline
- Supporting neuroplasticity and new synaptic connection formation
- Research into neurodegenerative disease therapeutics (Alzheimer's, Parkinson's)
- Nootropic stacking for individuals seeking enhanced learning capacity