Peptides for Traumatic Brain Injury — Evidence Review
Traumatic brain injury — concussion, post-concussive syndrome, and more severe TBI — has the largest peptide RCT data of any neurological indication, primarily driven by cerebrolysin trials. Semax…
Traumatic brain injury — concussion, post-concussive syndrome, and more severe TBI — has the largest peptide RCT data of any neurological indication, primarily driven by cerebrolysin trials. Semax and selank have Russian-research-program data. Other claimed nootropic peptides (dihexa, etc.) lack human evidence.
Peptides with the strongest evidence
Cerebrolysin
Porcine-derived peptide preparation studied in multiple TBI RCTs. The CAPTAIN II trial (Poon et al., 2015) and several other trials report improved Glasgow Outcome Scale scores at 90 days post-TBI. Meta-analyses pool the data with mixed effect-size estimates but generally favorable directionality. Mechanism includes neurotrophic, anti-apoptotic, and BBB-supportive actions.
Cerebrolysin is approved or used in many countries (notably Eastern Europe, Russia, parts of Asia) and not in the US — quality and source vary considerably for compounded versions.
Semax
Heptapeptide (ACTH 4-7 fragment) with neurotrophic action via BDNF modulation. Russian research program trials in stroke and TBI report improvement on cognitive and functional endpoints. Western replication is limited but emerging.
Selank
Anxiolytic peptide with neurotrophic and HPA-axis-modulating effects. TBI-specific data is limited; cognitive and post-concussive-symptom relevance is plausible mechanistically.
Supporting cast — preliminary data
Dihexa
Angiotensin IV-derived peptide with claimed neurotrophic and synaptogenic action in animal models. Often described as "1000x more potent than BDNF" — that figure comes from a single in vitro assay and does not represent in vivo performance. Zero human clinical trials. Anecdotal nootropic claims substantially outpace evidence.
What the evidence does not support
- BPC-157 or TB-500 as primary TBI therapy — animal data on nerve injury exists but is not TBI-specific
- Peptide therapy as substitute for standard TBI care: cognitive rehabilitation, vestibular rehabilitation, vision therapy, and graded return to activity protocols are first-line
- Self-directed peptide use during acute or sub-acute TBI without neurology oversight
Practical considerations
TBI care benefits from multidisciplinary management — neurology, neuropsychology, rehab medicine. Adjunctive peptide use, if pursued, should be coordinated with this team rather than self-directed.
For chronic post-concussive symptoms, semax and selank have lower acute-safety concerns than cerebrolysin and may be more practical for outpatient use. Cerebrolysin is typically administered in courses by IV or IM injection.
Where to source
- Cerebrolysin vendor rankings — limited; quality varies
- Semax vendor rankings — limited
- Selank vendor rankings — limited
Russian-research-program peptides have less independent third-party testing than the metabolic-peptide class.
What we don't know
- Whether cerebrolysin's TBI benefits replicate in larger Western RCTs
- Optimal timing of peptide therapy relative to injury (acute vs sub-acute vs chronic)
- Long-term outcomes beyond standard 90-day endpoints
- Whether dihexa will mature beyond preclinical into useful neurological therapy
Methodology
Read the full methodology.
This page is educational. TBI is a clinical entity with established multidisciplinary management. Peptide therapy is at best adjunctive and should be coordinated with the treating neurology and rehabilitation team.