Understand the source comparison
Peptides for Depression: Full Comparison
Before considering any peptide intervention, understand the evidence strength, administration route, documented mechanisms, and realistic outcome expectations across the most-studied compounds. Semax BDNF/NGF upregulation via melanocortin receptor activation I
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This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- Before considering any peptide intervention, understand the evidence strength, administration route, documented mechanisms, and realistic outcome expectations across the most-studied compounds.
- Semax
- BDNF/NGF upregulation via melanocortin receptor activation
- Intranasal
- 7 published human trials. All Russian or post-Soviet settings, sample sizes 38–112, no FDA Phase III data
- 600–900 mcg intranasal daily for 14 days
- Biologically plausible mechanism with measurable BDNF increases. Reproducibility in Western research settings needed before clinical recommendation
- Cerebrolysin
- Neurotrophic factor mixture from porcine brain tissue, promotes synaptic density restoration
- Intravenous
- 14 RCTs analyzed in 2023 systematic review, total 1,847 patients, strongest adjunctive evidence for depression
- 30mL IV daily for 21 days as adjunctive therapy
- Most robust clinical data of any peptide for depression. Adjunctive benefit documented, but IV route limits accessibility
- P21
- CREB modulation, hippocampal LTP restoration, synaptic plasticity enhancement
- Subcutaneous
- Preclinical rodent models only. No published human depression trials
- 1–5 mg subcutaneous weekly in research settings
- Promising preclinical data on memory and cognition. Human depression efficacy unproven
- Thymalin
- Immune modulation, reduces pro-inflammatory cytokines linked to depression pathophysiology
- 1 pilot study (64 participants) in post-viral depression. No placebo control
- 10 mg subcutaneous every other day for 10 doses
- Early-stage evidence in inflammation-driven depression. Requires controlled replication
- Dihexa
- Hepatocyte growth factor (HGF) mimetic, promotes synaptogenesis and dendritic spine formation
- Oral or subcutaneous
- Preclinical only. Cognitive enhancement documented in rodent models, no human depression data
- 5–10 mg oral daily or 1–2 mg subcutaneous 2–3×/week in research contexts
- Potent synaptogenic mechanism. Speculative for depression until human trials conducted