Cognitive Peptides
Nootropic and neuroprotective peptides, and the size of the human evidence base.
Most cognitive peptides trace back to Russian clinical research from the 1990s and 2000s, which is real published work but rarely replicated to Western regulatory standards. Semax and Selank both have human data behind them; the mechanisms proposed, BDNF upregulation and GABAergic modulation, are plausible and partly demonstrated. Dihexa sits at the other end, with headline rodent results and a retraction in its history. The grades below weigh replication, not novelty.
Semax
B-gradeA Russian nootropic peptide derived from ACTH that supports focus, memory, and neuroprotection by raising BDNF.
Selank
C-gradeA tuftsin-derived anxiolytic nootropic that lowers anxiety and supports calm focus without sedation or dependence.
Dihexa
F-gradeAn oral angiotensin IV analog studied as a memory aid in rodents, the foundational animal paper now carries a formal notice of concern, and no human trial exists.
Guides in this category
Best Peptides for Sleep
Compare the best peptides for sleep quality: DSIP, ipamorelin, CJC-1295, Selank, epithalon. Evidence-based rankings with dosing.
Best Peptides for Cognitive Enhancement
Compare the best nootropic peptides for focus, memory, and neuroprotection. Evidence-based rankings of Semax, Selank, and more.
Selank vs Semax
Selank vs Semax: mechanism, dosing, evidence grade, and side effects compared side by side, with citations.
Cognitive peptide questions
How many cognitive peptides are there?
This library covers 3 cognitive compounds, each graded from S (regulatory approval) to F (no usable evidence).
Which cognitive peptide has the strongest evidence?
Semax carries the highest research grade in this category at B. A Russian nootropic peptide derived from ACTH that supports focus, memory, and neuroprotection by raising BDNF.
What does the research grade mean?
The grade describes how well a compound has been measured in humans, not how well it works. S means regulatory approval; D means animal data only. Popularity and anecdote do not affect it.