Guide
Semax: A Research Peptide Overview
Semax is a synthetic heptapeptide used as a model peptide in cell-based laboratory research. This overview covers what it is, the pathways researchers study in vitro, how it is handled as a reference material, and why batch-level purity matters. It is written strictly for laboratory research context.
What Semax is
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment of adrenocorticotropic hormone, extended at the C-terminus with a Pro-Gly-Pro sequence that slows enzymatic breakdown. It carries CAS number 80714-61-0, the molecular formula C37H51N9O10S, and a molecular weight of 813.92 g/mol.
As a research reference material it is supplied as a lyophilized powder and characterised by HPLC for purity and mass spectrometry for identity.
Why it is studied
In the laboratory, Semax is used in melanocortin-receptor pathway research in cell models and in studies of neurotrophic-factor expression, including BDNF-related pathways.
It also appears in peptide-hydrolysis and stability research and serves as an analytical reference standard. These are in vitro research applications only, and no medical claims are made here.
Handling and storage
Semax is stored long-term at -20°C (-4°F), protected from moisture and direct light, and kept dry and sealed so the batch stays traceable for re-verification.
This overview does not cover preparation or use of any kind. That falls outside laboratory research reference use, and we do not provide that guidance.
Why purity and identity matter
Semax contains a methionine residue, and its oxidation state is one of the variables an analytical report is expected to pin down. A documented HPLC purity figure and a mass-spectrometry identity confirmation together describe both how clean the sample is and whether it is the right molecule.
This is why a per-batch Certificate of Analysis, one tied to the exact lot you receive, is more useful than a generic brand-level document.
How to verify a Semax batch
Before relying on any batch, confirm three things: purity (an HPLC percentage), identity (a mass-spectrometry confirmation), and a traceable lot number with a test date. If the supplier lets you look up that batch’s report, you can match the documentation to the vial in hand.
See our guide on how to read a peptide COA for a field-by-field walkthrough.
Regulatory status: common questions
Is Semax FDA approved? No. Semax is not an approved drug in the United States. In July 2026 an FDA advisory committee (the Pharmacy Compounding Advisory Committee) voted to recommend adding Semax to the 503A compounding list; a recommendation is not approval, rulemaking is still pending, and until it completes Semax remains unapproved. It is supplied strictly as a laboratory research reference material.
Is Semax legal in the US? Semax is not a scheduled substance under the Controlled Substances Act. It is lawfully supplied as a reference material for laboratory research, and for no other purpose; nothing on this site should be read as a claim otherwise.
What about its status outside the US? Semax was developed in Russia and is a registered pharmaceutical there. Foreign registration has no bearing on US status, where it remains unapproved.
Why a lyophilized vial and not a spray? Reference material is quantified by mass and stability-characterised in lyophilized form, which is what a per-batch certificate can actually describe. Pre-mixed and spray formats fall outside laboratory reference use, so we do not offer them.