Semax vs Selank: evidence, status and structure
A side-by-side look at Semax and Selank, using the data on each VALREXA profile. Neither comparison is a recommendation.
Key differences
- Both sit at the same evidence level: Early human.
- Their U.S. status differs: Semax falls under Compounding allowed (Not FDA-approved); Selank falls under Not FDA-approved (Not FDA-approved).
| Semax | Selank | |
| Research class | Neuroscience | Neuroscience |
| Human evidence | Early human | Early human |
| U.S. status | Not FDA-approved | Not FDA-approved |
| 2026 compounding decision | Allowed for 503A pharmacies under FDA enforcement discretion (Oct 2026) | — |
| Amino acids | 7 | 7 |
| Molecular weight | ~813.9 Da | ~751.9 Da |
| Formula | Varies by form | Varies by form |
| Sequence | MEHFPGP | TKPRPGP |
| Research period | 1980s | 1970 |
| Safety summary | Not FDA-approved as a drug in the United States. | Not FDA-approved as a drug in the United States. |
How they differ
Both are heptapeptides developed at the Institute of Molecular Genetics in Moscow, and both carry the same Pro-Gly-Pro tail added to slow breakdown. Semax is built on a fragment of ACTH (the stress hormone) and has been studied mainly for cognition and stroke. Selank is built on tuftsin, an immune-system peptide, and has been studied mainly for anxiety. Neither is FDA-approved, and most studies come from Russia.
What each one is
Semax: Synthetic ACTH(4–10)-related heptapeptide studied in neuroscience. Molecular weight, sequence, research history, human evidence and regulatory status.
Selank: Synthetic tuftsin-derived heptapeptide studied in neuroimmune signaling. Molecular weight, sequence, research history, human evidence and regulatory status.
Educational reference only. Nothing here is medical advice, a treatment recommendation, or dosing or sourcing guidance. Report an error.