Semax dosage and evidence

What is Semax?

How does Semax work?

It raises BDNF and NGF, two proteins that help brain cells grow and connect. It also works on the brain's melanocortin and dopamine systems. The idea is that this protects brain cells and helps them adapt.

What have studies in people found about Semax?

Semax has real studies in people, and almost all of them are Russian. Several hundred patients took part, with stroke, long-term poor blood flow to the brain, optic nerve disease or motor neuron disease. The studies were published in Russian journals. Most had no dummy treatment, and everyone knew who got the drug. No group outside Russia or Ukraine has ever repeated them.

• Poor blood flow to the brain: 187 patients at different stages were checked with nerve, thinking, ultrasound, brain scan (MRI) and heart tests. The authors report that symptoms improved, the disease stopped getting worse, and fewer strokes and mini-strokes happened during follow-up. Side effects were few. The published summary describes no dummy group and no outside judge of the results.
• Stroke rehab: 110 stroke patients (43 men and 67 women, average age 58.0) were split into an early rehab group (89 days) and a late rehab group (214 days). Each group was split again into semax and no semax. The dose was two 10-day courses of 6,000 mcg a day, 20 days apart. A brain growth factor in the blood called BDNF rose and stayed high with semax, and a daily-living score improved faster. People were not assigned by chance and nobody got a dummy treatment. So the changes cannot be separated from the choice of who got treated.
• Recent stroke: 30 patients got semax in the first days after a major stroke. They were compared with 80 patients with strokes of similar severity and location who got usual care alone. The authors report that weakness and other problems faded faster, especially movement. They give the best daily doses as 12 mg for moderate strokes and 18 mg for severe ones, over 5 and 10 days. Patients were not assigned by chance and nobody got a dummy treatment.
• Motor neuron disease: 27 patients took 12 mg a day up the nose in two 10-day courses with a two-week break. Nerve and muscle tests and rating scales were done at six points. The authors say semax did not change the nerve damage or the clinical ratings. Only the patients' overall quality-of-life score went up, most at day 10. PubMed lists this as a controlled trial, but the summary describes groups treated one after another, with everyone knowing who got the drug.
• Optic nerve disease: patients whose optic nerve was damaged by poor blood flow, toxins, allergy or inflammation, some with partial nerve loss, were put into three groups. One got nose drops, one got the drug pushed through the nose with a mild electric current, and one was a comparison group. Everyone also got standard treatment. The authors report sharper vision, a wider field of view, better nerve signals and better colour vision. The summary does not say how many people were in each group.

What this does not tell you: Every study gave semax on top of standard hospital treatment, so its own part cannot be pulled out. The biggest ones describe no dummy treatment, and everyone knew who got the drug. The one study that used objective nerve tests found no effect on them. Nothing here has been repeated outside the Russian-language research. No trial has tested the nasal doses sold online in healthy people for focus, memory or mood. That is what most buyers outside Russia use it for. And no study reports what happens after more than a few weeks of use.

What do people who took Semax report?

This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.

• Focus and drive are what people report, frequently described in terms of stimulant-like productivity without the physical jitteriness, and several describe the effect persisting for a period after stopping.
• Anxiety is the sharpest disagreement in the whole discussion. A substantial group report it makes anxiety worse and describe it as anxiety-inducing, particularly at higher doses, while others report the opposite. Both positions are held by long-term users and neither is fringe.
• Dose sensitivity is the most common explanation offered for that split, with the recurring advice being that going higher makes things worse rather than better.
• Burnout and tolerance are described after extended runs, and cycling or pairing with Selank is the usual response to that.
• Most experienced posters say it is better taken on its own than stacked, which is unusual advice in a community that stacks everything.
• Reports of no noticeable effect exist and are not rare, and route of administration and product quality are the usual explanations offered for them.

Sources: Brain Health and Nootropic Stacks threads on LongeCity, including multi-page experience threads, found by site-restricted search and read directly, September 2026. Nothing above is attributed to any specific post and no post is reproduced.

The state of the research

The evidence, in charts

The studies we cite

• Study in people2018
  The efficacy of semax in the treatment of patients at different stages of ischemic stroke

  This is the study the stroke claim leans on, and it was not built to prove anything. 110 people recovering from a stroke were given courses of Semax. A brain growth protein in their blood rose, and their scores for everyday tasks improved faster. There was no dummy treatment to compare against, and nobody was kept in the dark about what they were getting. So there is no way to separate the drug from ordinary recovery after a stroke.

  Russian clinical study of 110 post-stroke patients: Semax courses raised plasma BDNF and were associated with faster Barthel index improvement; not a blinded placebo-controlled trial.

  PMID 29798983 Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova
• Study in people1997
  [Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study)]

  This is a real study in real stroke patients, and its design cannot size the effect. Thirty people were given semax in the first days after a stroke, alongside their usual hospital care. Eighty others with strokes of similar severity got the usual care alone. Nobody was picked by chance, and nobody was kept in the dark. The authors report that weakness and other deficits faded faster on semax. The work is Russian, and no Western group has repeated it.

  30 patients treated in the acute period of hemispheric ischemic stroke against a control group of 80 patients matched for severity and location; faster regression of general cerebral and focal deficits reported, at 12 mg daily for moderate and 18 mg daily for severe strokes. Not randomized, not placebo-controlled.

  PMID 11517472 Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova
• Study in people2005
  [Semax in prevention of disease progress and development of exacerbations in patients with cerebrovascular insufficiency]

  The largest semax study in people has nothing to compare itself against. Doctors treated 187 patients with poor blood flow to the brain and followed them over time. The authors report that symptoms improved, that decline slowed, and that fewer strokes and mini strokes happened. Everybody in the study got semax. There was no dummy treatment and no untreated group, so there is no way to know what would have happened anyway. The work is Russian and nobody outside has repeated it.

  187 patients with cerebrovascular insufficiency: the authors report clinical improvement, stabilisation of progression and a reduced rate of stroke and transient ischemic attack, with few side effects and good tolerability in older patients. No placebo group is described in the indexed abstract.

  PMID 15792140 Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova
• Study in people2007
  [The study of chronic partial denervation and quality of life in patients with motor neuron disease treated with semax]

  Semax was measured against a nerve test and it did nothing. Twenty seven people with motor neuron disease took semax up the nose for two ten day courses. Their nerve and muscle testing did not change, and neither did the clinical ratings of their disease. The only score that moved was how they rated their own quality of life, biggest at day ten. That is the softest measure in the study and the one most easily swayed by knowing you are being treated.

  27 patients given intranasal Semax 12 mg daily in two 10 day courses: the authors state Semax did not influence chronic partial denervation on needle EMG or the clinical estimates, and report improvement only in the total quality of life score, largest at day 10.

  PMID 18379501 Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova
• Review of studies2026
  July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee

  The official FDA meeting record. An FDA advisory panel discussed Semax on July 24, 2026, for possible use in compounding.

  Official FDA meeting record: Semax (free base and acetate) was discussed on July 24, 2026 for possible inclusion on the 503A bulk drug substances list.

  Source U.S. Food and Drug Administration
• Animal study2006
  Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus

  In rats. One dose raised BDNF, a brain growth protein, about 1.4 times in the memory part of the brain. The rats also learned a task better.

  A single 50 mcg/kg dose raised hippocampal BDNF protein 1.4-fold, trkB phosphorylation 1.6-fold and BDNF mRNA 3-fold in rats, alongside improved conditioned avoidance learning.

  PMID 16996037 Brain Research
• Animal study2007
  Neurotrophin gene expression in rat brain under the action of Semax, an analogue of ACTH 4-10

  In rats. A follow-up study mapped how Semax changed the BDNF and NGF genes across parts of the brain.

  Follow-up work mapping Semax-driven changes in BDNF and NGF gene expression across rat brain regions.

  PMID 17353092 Neuroscience Letters