Semax
A Russian nootropic peptide based on a fragment of ACTH, used as a nasal spray. People run it for focus and mental clarity, for memory and learning, and for its studied neuroprotective effects, often stacked with Selank for calm focus.
Where to buy Semax, cheapest first.
Prices from 9 vendors across the market. We link straight to each vendor’s product page and grade vendors on public lab data, so you’re not just chasing the lowest number.
Semax
What Semax actually does.
The simple version first, then a little more for the curious. No biochem degree required.
It nudges your brain to make more BDNF, a growth factor that supports learning and memory, while gently tuning dopamine and serotonin signaling, so people feel sharper and more focused.
How it works
Semax is a synthetic heptapeptide based on the ACTH(4-10) fragment, but without the hormonal, adrenal-stimulating part. Its headline effect is rapidly raising BDNF and its TrkB receptor in the brain, the signaling that supports neuron growth and synaptic plasticity.
Where it acts
Sprayed in the nose, it is studied for reaching the brain partly through the olfactory pathway, which helps it bypass some of the blood-brain barrier. It is researched mostly for attention, memory, and protecting brain tissue under stress, such as after ischemia.
What people notice
People report a clean lift in focus and verbal fluency, steadier mood, and easier recall within a day or two. The plasma half-life is only minutes, but the BDNF response can last around 24 hours, which is why it is dosed daily rather than constantly.
Honest caveat: most of the human evidence comes from Russian clinical use, where Semax is an approved medicine, and has not been broadly replicated in large Western trials. The rest is animal and lab work. It is not approved by the FDA and is sold strictly for research use only. None of this is medical advice, talk to a licensed provider before starting anything.
How to take it.
Semax is used as a nasal spray, dosed in micrograms per spray into each nostril. It isn't a meaningful oral peptide because stomach acid breaks it down, so the intranasal form is what people run. Some research also uses subcutaneous injection, but nasal is by far the most common. The routine is below; for cycling and timing, see the full guide.
Reconstitute into a spray bottle
Add bacteriostatic water to the freeze-dried vial, then transfer into a small nasal-spray bottle. A common mix is a 10mg vial in enough water to give roughly 300mcg per spray. Swirl gently, don't shake.
Prime the pump
With a fresh bottle, pump a few sprays into a tissue until a fine, even mist comes out. This makes sure each later spray delivers a consistent dose.
Spray per nostril
Tilt your head slightly forward, close one nostril, and give one spray into the other while breathing in gently. A common pattern is one spray per nostril, so about 600mcg total, once or twice a day.
Alternate nostrils and store cold
Switch which nostril you start with to avoid irritating one side. Keep the bottle in the fridge between uses and out of direct light.
Typical Semax dose: about 300 to 600 mcg per day intranasally for general focus, split into one or two doses, with research and clinical protocols often running short courses of around 10 to 14 days rather than continuously.
How to cycle Semax.
How long people run Semax, when to take a break, and the honest reasoning behind it.
Used in short courses or situationally.
A cycle just means a defined run of time on the peptide, followed by a break. For Semax the common pattern is a short course of roughly 10 to 14 days, then time off, rather than running it every day forever.
Why not just run it forever? Mostly because the long-term human safety data outside Russian clinical use does not really exist yet. The cautious and widely followed approach is to run a focused course when you need it, then stop.
- Keep doses earlier in the day so the focus effect does not interfere with sleep.
- Run a defined course of around 10 to 14 days rather than open-ended daily use.
- Take a real break between courses. If you find you need it constantly, that is a conversation for a licensed provider.
Want the full picture, on and off periods, the washout, stacking, and keeping your results? Read how peptide cycling works →
What's actually in the vial.
For 4 of these vendors we link the per-batch certificate itself (a specific lab report, COA PDF, or certificate image), and the purity below is read straight off that certificate. The rest link to the vendor's general lab-results page. We don't run the labs ourselves and we don't show a purity number unless it's printed on a certificate we link, so you can open the document and check it against the batch yourself.
| Vendor | Purity (per COA) | Batch / report | Certificate |
|---|---|---|---|
| EZ Peptides | 99.105% | EZP-SEMX1005182026-10 | Janoshik report ↗ |
| Midwest Peptide | 99.951% | MPSX001 | View COA ↗ |
| Onyx Biolabs | 99.942% | SEM-2026-0320 | View COA ↗ |
| Next Gen Peptides | 99.92% | 2M26 | COA (PDF) ↗ |
| Penguin Peptides | see lab page | not shown | Lab results ↗ |
What people pair it with.
Semax is often run on its own, but the nootropic community has a couple of pairings it reaches for when calm, focused cognition is the goal.
Focus & anxiety
The classic Russian nootropic pair. Semax brings the stimulating, BDNF-driven focus, while Selank takes the edge off anxiety and overstimulation. Together people describe a calm, clear-headed focus rather than a jittery push.
View stack →Brain & recovery
A neuroprotection-leaning combination. Both are studied for supporting brain tissue and cognition, so people stack them during demanding mental periods or recovery. Heavier and more involved than running Semax alone.
View stack →Focus & mood
Pairs Semax's focus angle with NAD+ for energy and cellular support. A lighter everyday clarity stack people experiment with, though evidence for the combination specifically is thin.
View stack →In the same corner.
Other cognitive and nootropic peptides people compare against Semax.
Questions, answered straight.
Is Semax legal?
Semax is an approved medicine in Russia, but it is not approved by the FDA or EMA. The vendors we compare offer it strictly for research use only, not for human use. As of 2026 it is not specifically on WADA's prohibited list, but as an unapproved substance it could fall under broader banned categories, so competing athletes should treat it as high-risk. Rules vary by country, so check what applies where you are.
What does research use only actually mean?
It means the product is sold for laboratory and research purposes, not as a supplement or medicine for people. It has not been reviewed or approved for human use by the FDA. We aggregate prices and public lab data so you can see the landscape; what you do with that is between you and a licensed provider.
How do I store it?
Keep the sealed, freeze-dried vial in the fridge and out of direct light. Once you mix it with bacteriostatic water and load a nasal-spray bottle, keep it refrigerated and use it within a few weeks. Don't freeze a reconstituted bottle.
How often do people dose it?
A common pattern is about 300 to 600 mcg per day, split into one or two doses, often run as short courses of 10 to 14 days rather than continuously. The stronger, longer-acting N-acetyl version is dosed a little lower for a similar effect.
Nasal spray or injection?
Nasal is by far the most common, because it is needle-free and the peptide is studied for reaching the brain through the olfactory pathway. Some research uses subcutaneous injection, but for most people the spray is simpler and just as practical. Semax isn't an oral peptide, so skip any capsule versions.