The answer so far
Two small reports described changes in brain-scan patterns after Semax, or after Semax and Selank in separate groups. The measurements do not by themselves establish better attention, memory or relief from anxiety. The later study did not test the two peptides as a combination.12
On this page
Why do brain-scan results sound persuasive?
A coloured image of a brain can look like a direct picture of focus or calm. In these studies the researchers were asking a narrower question: did a measured signal pattern differ after a peptide and a comparison? That can help scientists form hypotheses, but it does not by itself show that someone can concentrate better or feels less anxious. For the everyday questions behind the names, start with Semax and Selank for focus and stress.12
What does resting-state fMRI measure?
Functional MRI, or fMRI, detects changes related to blood oxygenation and flow, which can be associated with brain activity. In resting-state research, participants are not performing a particular assigned task while signals are recorded. Researchers can look at whether signals from different regions vary together over time; this is called functional connectivity. It is a statistical relationship, not a photograph of thoughts or a direct measurement of better attention. Movement, breathing and other factors can also affect signals.45
What did the 2018 Semax study report?
In the report’s abstract, 14 healthy participants received a particular intranasal Semax preparation and ten received placebo. Scans were taken before and at five and 20 minutes afterwards. The authors reported a difference in the mapped extent of part of the default-mode network, a pattern of brain regions studied when people are not performing a specified task. The abstract does not describe randomisation or blinding, and a short network measurement is not evidence of improved daily memory, attention or lasting safety.1
What did the 2020 study add?
A second report included 52 healthy participants who received Semax, Selank or placebo in separate groups. The abstract describes scans before and at five and 20 minutes after administration and reports differences in how signals in selected brain regions varied together. Its abstract does not state group sizes, randomisation or blinding, and it describes administration as “injection” without making the route clear. We reviewed the abstract and FDA’s summary, not a full methods report. Neither report establishes how long a signal change lasts or whether it helps a person.23
- 2018: 24 participantsSemax and placebo groups; resting-state network topography was examined.
- 2020: 52 participantsSeparate Semax, Selank and placebo groups; researchers examined signal relationships.
- Overlap unclearThe FDA said the Semax participants appeared similar; the samples should not simply be added.
- A different questionAttention, memory and anxiety require outcomes that directly measure those experiences.
Were the peptides tested together?
The 2020 abstract describes separate Semax, Selank and placebo groups, not a group receiving the two peptides together. It therefore cannot tell us whether a combination improves focus or stress, whether it is better than either alone, or what additional risks it might have. FDA noted that the Semax participants in the two imaging reports appeared similar and that overlap was unclear, so their sample sizes should not simply be added.23
What about the studies in people with anxiety?
Some Selank reports asked a different question by comparing it with an anxiety medicine in people with anxiety-related conditions. One 2014 English abstract reports an anxiety-reducing effect, but does not provide enough details about allocation, blinding, placebo or numerical group differences to establish equivalence or a causal effect. Its full Russian-language report was not reviewed here. An anxiety symptom score, a scan pattern and a memory test answer different questions. Read the Selank profile for the available reports. For a closer look at the active-medicine and add-on comparisons, read the Selank anxiety studies.6
What would help answer a reader’s question?
A stronger study would define the product and group, compare it with an appropriate control, measure a relevant outcome such as sustained attention or anxiety symptoms, and follow participants long enough to assess benefits and harms. A scan might add context, but it would not replace those outcomes. For persistent difficulties, a qualified clinician can help consider sleep, stress, medicines or other possible causes. Explore focus and memory, stress and mood or the Semax profile. For a different population and longer-term question, see Semax and stroke recovery.126
Sources, kept close.
Selected supporting sources; this is not a complete literature review.
- Effects of Semax on the Default Mode Network of the BrainBulletin of Experimental Biology and Medicine / PubMed · Small placebo-comparison human imaging study; 2018
- Functional Connectomic Approach to Studying Selank and Semax EffectsDoklady Biological Sciences / PubMed · Primary human imaging report, abstract reviewed
- FDA Pharmacy Compounding Advisory Committee Semax briefingU.S. Food and Drug Administration · Regulator briefing
- Functional Magnetic Resonance Imaging (fMRI): glossaryNational Institute of Biomedical Imaging and Bioengineering · Public-health imaging glossary
- Resting-state fMRI confounds and cleanupNeuroImage / PubMed Central · Neuroimaging methods review
- A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disordersZhurnal Nevrologii i Psikhiatrii / PubMed · Primary clinical report, Russian-language article with English abstract, 2014