What is Semax?
Semax is a synthetic heptapeptide derived from a fragment of the hormone ACTH (specifically ACTH 4-7), extended by the end Pro-Gly-Pro, which makes it more stable (Dmitrieva et al., 2010). It was developed in Russia, where it is used clinically mainly around stroke and cognitive topics.
In a research context, Semax is known as a nootropic: it is meant to support focus, memory and stress resilience. It is used nasally or subcutaneously, dosed in micrograms. It ships as a freeze-dried powder you dissolve in bacteriostatic water.
Comparison
Semax and its relatives in the lexicon
Semax in different forms and the related Selank, as described in the TPD lexicon. Tap a card to open its entry.
How it works
Semax acts at several points in the brain. Best documented is that it drives the production of nerve growth factors like BDNF and NGF, messengers important for learning, memory and the protection of nerve cells. It also influences the dopaminergic and serotonergic systems.
In a research context, users mainly report clearer focus and better resilience under stress. The effect sets in fairly fast: the peptide itself is only briefly measurable in the body, but the effects it triggers last longer.
Where it acts
Where Semax acted in studies
Tap a point or a card. Colour = target, grey = seen in studies.
Known targets1
Compound PubChem CID 9811102 (Semax): one described target, More produced and activated, indirectly via BDNF. Direct binding of Semax is not shown.
- Gene
- NTRK2
- UniProt
- Q16620
- ChEMBL
- CHEMBL4898
- Action
- More produced and activated, indirectly via BDNF. Direct binding of Semax is not shown
What you need
What you need depends on whether you use it nasally or subcutaneously:
- The Semax vial with the freeze-dried powder
- Bacteriostatic water to dissolve it
- For nasal: a small nasal spray bottle or a dropper
- For subcutaneous: U-100 insulin syringes
- Alcohol swabs and, for injection, a sealable sharps container for used needles
Reconstitution
The powder is dissolved in bacteriostatic water. How much water you add sets the concentration, that is, how many micrograms are in a drop or in a syringe unit.
Use the peptide calculator for this: it shows the concentration and, for subcutaneous use, the units per dose. You can use the same solution nasally as drops, in which case the concentration helps you estimate the micrograms per drop.
When dissolving, just add the bac water, it does not matter if it hits the powder directly. Then swirl or shake until everything has dissolved, both are fine.
Step by step
Dissolving the powder
Four steps, the same for every vial size.
- 1Wipe the cap
Clean the rubber stopper with an alcohol swab.
- 2Add BAC water
Just add it, it does not matter if it hits the powder directly.
- 3Swirl or shake
Until everything has dissolved, both are fine.
- 4Draw up
With the U-100 insulin syringe.
Use (nasal or subcutaneous)
Dosing
Dosing
Dosing, titration and syringe
Loading the dosing information …
- Getting started and stepping up, drawn as a staircase
- Units on the U-100 syringe for every step
- How long one vial lasts
What the research shows
The evidence on Semax is mixed, which deserves to be said honestly: there is a solid preclinical base (mainly on BDNF/NGF and neuroprotection) and clinical studies from Russia, for example in ischemic stroke, where Semax is used as a neuroprotectant. Large Western double-blind studies on nootropic use in healthy people are largely missing, though. Meaning: the mechanism is well described, the everyday effects rest more on mechanism plus user experience than on large RCTs.
The studies with links are in the source block below.
Study results
What the trials measured
Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.
BDNF and its receptor in the hippocampus1
Peak after a single dose of Semax, as a multiple of animals without Semax
Values according to the abstract (1.4, 1.6, 3 and 2-fold). The rats also showed more learned avoidance responses. Not tested like this in humans.
How large the human studies were26
Number of participants per group
The abstracts give no measured values on the effect. According to Gusev 1997 neurological deficits, especially of movement, regressed faster with Semax. According to Lebedeva 2018 part of the resting network in the frontal brain was larger after Semax than on placebo.
Research status
Where the research stands
Semax is not listed on ClinicalTrials.gov. The human studies come from Russia and are only published as journal articles. As of 26 Oct 2026. 7
Side effects
Semax is considered well tolerated. Mainly mild things are reported: with nasal use, irritation of the nasal lining, occasionally head pressure. Because it is activating, using it too late can disturb sleep. Serious side effects are rarely described in the literature, but data on very long continuous use are limited, so phases make more sense than continuous running.
Practice
A few things get more out of Semax:
-
Timing: earlier in the day, not late evening, since it is activating.
-
Use in phases rather than endlessly, that keeps the effect fresh.
-
Sleep and basics first
A nootropic does not replace sleep, it builds on it.
-
Work cleanly with nasal use: keep the bottle cool and do not share it.
Storage
The undissolved powder is robust, normal room temperature (around 20 to 25 degrees) is fine, ideally kept in the dark. The reconstituted solution goes into the fridge (2 to 8 degrees) and stays stable there for at least 4 to 6 months with barely any loss of potency, in practice considerably longer. The bacteriostatic water brings a preservative. Especially with nasal use, keep the bottle clean.
Shelf life
How long it keeps
Robust, no fridge needed.
At least 4 to 6 months with barely any loss of potency. Keep the bottle clean when used nasally.
- Keep it dark
- Dissolved: 2 to 8 degrees
- Note the mixing date on the vial
