Compound comparison

Semax vs Selank

Semax and selank are both Russian-developed peptides studied for cognitive effects, frequently discussed as a pair.

Updated September 2026
This page is an educational comparison, not medical advice, and it does not recommend either compound. Regulatory status differs between them; see the table below.

Semax and selank are both synthetic peptides developed in Russia and are frequently discussed together because they share that origin and a similar gap between established Russian clinical use and limited Western data. Semax is a synthetic ACTH analog. Selank is a synthetic tuftsin analog. Neither is FDA-approved.

At a glance

SemaxSelank
What it isSynthetic ACTH analog studied for neuroprotective, cognitive-enhancing, and mildly anxiolytic effectsSynthetic tuftsin analog studied for anxiety reduction and cognitive enhancement, developed in Russia
How it's thought to workStudied for modulating BDNF and NGF expression and enhancing serotonergic and dopaminergic neurotransmissionStudied for modulating GABA and serotonin neurotransmission and supporting immune function via tuftsin pathways
Regulatory statusApproved in Russia for cognitive enhancement and stroke recovery; not FDA-approvedApproved in Russia for anxiety disorders; not FDA-approved
Strength of evidenceEstablished Russian clinical use; Western clinical data is limitedEstablished Russian clinical use; Western clinical data is limited
Reported side effectsGenerally well-tolerated; rare reports of irritability or overstimulationMinimal; occasional fatigue and mild drowsiness reported
Common vial sizes5mg, 10mg5mg, 10mg
Mixing math example5 mg + 1 mL BAC water = 5,000 mcg/mL, 50 mcg per unit5 mg + 1 mL BAC water = 5,000 mcg/mL, 50 mcg per unit

Key differences

Semax is studied for modulating BDNF and NGF expression and enhancing serotonergic and dopaminergic neurotransmission, with research describing neuroprotective effects through multiple pathways. Selank is studied for modulating GABA and serotonin neurotransmission and supporting immune function through pathways associated with tuftsin, with anxiolytic effects reported without sedation. Tuftsin itself is an immune-modulating peptide naturally present in the body, distinct from the ACTH pathway semax is built on.

Semax is approved in Russia for cognitive enhancement and stroke recovery. Selank is approved in Russia for anxiety disorders. Neither is FDA-approved, and clinical data from Western countries is described as limited for both, with most of each compound's formal clinical record coming from the Russian medical context rather than from Western trials.

Semax is generally described as well-tolerated, with rare reports of irritability or overstimulation. Selank's reported side effects are also minimal, with occasional fatigue and mild drowsiness reported.

What the research covers

Semax is approved in Russia for cognitive enhancement and for stroke recovery, with clinical data from Western countries described as limited. Selank is approved in Russia for anxiety disorders, with the same limitation on Western clinical data. Most of the formal regulatory review and clinical use for both compounds comes from the Russian medical context rather than Western trials.

Frequently asked questions

What is the difference between semax and selank?

Semax is an ACTH analog studied for neuroprotective and cognitive effects and approved in Russia for cognitive enhancement and stroke recovery. Selank is a tuftsin analog studied for anxiety reduction and approved in Russia for anxiety disorders.

Is semax or selank FDA-approved?

Neither is FDA-approved. Both are approved in Russia for their respective indications.

Which has more human research, semax or selank?

Both have an established clinical record in Russia and limited clinical data from Western countries; neither has substantial Western trial data.

Are semax and selank the same thing?

No. They are distinct molecules, an ACTH analog and a tuftsin analog respectively, studied for different primary effects despite their shared Russian origin.

Both entries, plus the calculator

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