What is Semax?
Semax is a small lab-made peptide — a chain of seven amino acids: Met-Glu-His-Phe-Pro-Gly-Pro. (A peptide is just a short chain of amino acids, the building blocks that make up proteins.) It's built from a small piece of a natural body hormone called ACTH, with a short Pro-Gly-Pro tail added on the end so the body breaks it down more slowly. One important point: even though it comes from a piece of ACTH, Semax does not raise the stress hormone cortisol the way ACTH does. In the research, it's usually described as a 'nootropic' (studied for thinking and memory) and neuroprotective (studied for protecting brain cells) peptide.
Semax was developed by scientists at the Institute of Molecular Genetics of the Russian Academy of Sciences, and most of the published work on it comes from that group. One thing to be clear about: Semax is only for laboratory research. It is not a medicine, and it is not for use in people or animals.
The quick version
A seven-piece peptide
Built from a piece of the hormone ACTH, with a small tail added — and it does not raise the stress hormone cortisol.
The brain-growth angle
Research reports Semax bumps up BDNF, a natural growth signal for brain cells, in the memory area of model animals.
Research use only
Studied in memory, brain-cell protection, and stress models — never for people or animals.
99%+ pure
Double-checked by lab testing (HPLC and LC-MS) and shipped with a certificate for every batch.
Explore research-grade Semax
99%+ pure, with a certificate of analysis for every batch, and fast U.S. shipping — for laboratory research use only.
View SemaxHow Semax is thought to work
Scientists have looked at Semax along a few different paths at once. The theme that keeps coming up is a link to two things: brain-cell growth signals and the brain's chemical messengers (like dopamine and serotonin):
- The BDNF growth signal — research reports that a single dose of Semax raised levels of BDNF (a natural growth signal for brain cells) and switched on its docking point, called TrkB, in the memory area of the rat brain.
- Turning genes on — studies describe quick, area-specific changes in the genes for BDNF and another growth signal (NGF) in the brain soon after it's given.
- Brain messengers — Semax has been looked at for nudging the dopamine and serotonin systems (two of the brain's chemical messengers) in parts of the rodent brain.
This link to brain-cell growth signals is the main reason Semax draws research interest, and it's often the explanation pointed to in studies of learning behavior and brain-cell protection in lab models.
How Semax compares to similar compounds
Semax often comes up next to Selank, another lab-made peptide from the same Russian research programs. Both are short peptides studied in brain research, but they're built from different starting molecules and are studied for different things:
| Compound | Built from | What scientists study it for | Type |
|---|---|---|---|
| Semax | A piece of ACTH | Memory / brain-cell protection | Short peptide (7 pieces) |
| Selank | A copy of tuftsin | Calm / stress models | Short peptide (7 pieces) |
| Melanotan II | Related to ACTH | The melanocortin system | Ring-shaped peptide |
Peptora carries research-grade versions of several related peptides, including Semax and Selank — each with its own certificate of analysis.
What scientists actually study it for
In the lab, Semax usually comes up in a few connected areas:
- Thinking and memory — behavior tests have been used to look for memory and learning changes in rodents.
- Brain-cell protection — lab and some human studies have looked at Semax in strokes and other stressed-brain models.
- Growth signals — BDNF, NGF, and their docking points have been measured as possible explanations.
- Stress and mood — long-term-stress tests have been used to look for calming, anti-stress effects in animals.
Purity and testing (why the certificate matters)
In research, your results are only as trustworthy as the material you start with. Every batch of Semax from Peptora is checked to 99%+ purity by HPLC, confirmed by a second test (LC-MS) that proves it's the right molecule, and run through a full quality-control panel before it ships. Every order comes with a certificate of analysis (COA) for that exact batch.
Researchers often choose Peptora because this paperwork is standard here, not an extra. To learn what the numbers on a certificate mean, see the guide on the certificate of analysis.
How it's handled in the lab
Semax ships as a freeze-dried powder (a dry powder with the water removed). Before it's used in research, it's mixed with bacteriostatic water — a special sterile water, sold separately. A little care keeps the peptide intact so the results stay reliable:
- 1Let the sealed vial warm up to room temperature before opening it.
- 2Add the water slowly down the side of the vial, then swirl gently — don't shake.
- 3Wait until the powder is fully dissolved before drawing anything out.
- 4Keep the mixed solution in the fridge, away from light.
Step-by-step details are in the reconstitution guide. Doing these the same way every time is one of the easiest ways to keep research consistent.
Scientific references
Semax has been studied in cells, animals, and some human research over about two decades. The studies listed below are here for background, from PubMed. They describe research on the compound itself — not the laboratory research product Peptora supplies.
- 1Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Res. 2006;1117(1):54-60. doi:10.1016/j.brainres.2006.07.108.
- 2Eremin KO, Kudrin VS, Saransaari P, et al. Semax, an ACTH(4-10) analogue with nootropic properties, activates dopaminergic and serotoninergic brain systems in rodents. Neurochem Res. 2005;30(12):1493-1500. doi:10.1007/s11064-005-8826-8.
- 3Agapova TY, Agniullin YV, Shadrina MI, et al. Neurotrophin gene expression in rat brain under the action of Semax, an analogue of ACTH 4-10. Neurosci Lett. 2007;417(2):201-205. doi:10.1016/j.neulet.2007.02.042.
- 4Glazova NY, Manchenko DM, Volodina MA, et al. Semax, synthetic ACTH(4-10) analogue, attenuates behavioural and neurochemical alterations following early-life fluvoxamine exposure in white rats. Neuropeptides. 2020;86:102114. doi:10.1016/j.npep.2020.102114.
- 5Inozemtseva LS, Yatsenko KA, Glazova NY, et al. Antidepressant-like and antistress effects of the ACTH(4-10) synthetic analogs Semax and Melanotan II on male rats in a model of chronic unpredictable stress. Eur J Pharmacol. 2024;984:177068. doi:10.1016/j.ejphar.2024.177068.
- 6Gusev EI, Martynov MY, Kostenko EV, et al. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(3 Vyp 2):61-68. doi:10.17116/jnevro20181183261-68.
Explore research-grade Semax
99%+ pure, with a certificate of analysis for every batch, and fast U.S. shipping — for laboratory research use only.
View SemaxKey takeaways
- Semax is a small lab-made peptide (Met-Glu-His-Phe-Pro-Gly-Pro), built from a piece of the hormone ACTH — but it does not raise the stress hormone cortisol.
- Scientists study it as a thinking-and-memory ('nootropic') and brain-cell-protecting peptide, mostly in memory and brain-protection models.
- Published work reports that it raises BDNF (a brain-cell growth signal) and its TrkB docking point, and nudges the dopamine and serotonin systems in lab models.
- Much of the research comes from a single Russian research group and is still evolving, not clinically settled.
- Every batch is 99%+ pure (checked by HPLC and LC-MS) and comes with a certificate of analysis, supplied for research use only.
Frequently asked questions
This article is intended solely as an educational summary of publicly available scientific literature. Products offered by Peptora are supplied exclusively for laboratory research purposes and are not approved for human or veterinary use. The information presented should not be interpreted as medical advice, treatment recommendations, or clinical guidance.
