HomeCognitive & Nootropic › Semax

Nootropic / neuroprotective peptide (ACTH(4-10) analog)

Semax

Research use only

Written by pep4U Editorial Team · Last reviewed July 8, 2026

A synthetic modified ACTH fragment used as a cognitive-enhancing and neuroprotective agent (nasal spray or injection).

Class / typeNootropic / neuroprotective peptide (ACTH(4-10) analog)
CategoryCognitive & Nootropic
Status (Jul 2026)Research use only

Key points

  • A Russian nootropic peptide (an ACTH fragment) used for focus, memory and neuroprotection.
  • Raises BDNF - a key brain-growth factor - without ACTH's hormonal effects.
  • Approved as a medicine in Russia; research-use-only in the US.
  • Usually a nasal spray; reported as a 'clean,' non-stimulant focus boost.

Overview

Semax is a synthetic modified fragment of the hormone ACTH, developed and marketed in Russia as a neuroprotective and cognitive-enhancing drug. Importantly, the modification strips out ACTH's hormonal (adrenal) activity, leaving the brain effects.

In the US it isn't approved and is sold as a research chemical, typically used as a nasal spray or injection.

How it works

Semax rapidly increases BDNF (brain-derived neurotrophic factor) and its receptor in the hippocampus, and modulates dopamine and serotonin signaling. BDNF supports neuroplasticity - the brain's ability to form and strengthen connections.

What the research shows

In Russia it's used clinically for ischemic stroke, transient ischemic attack and cognitive disorders, backed by domestic clinical use and strong preclinical BDNF data. Rigorous Western placebo-controlled trials are limited, so much of the evidence is Russian and not FDA-reviewed.

Benefits

Users report improved focus, mental clarity, processing speed and mood, often with fast onset and without stimulant jitters or a crash.

Strong neuroplasticity/BDNF rationale and a track record of clinical use abroad.

Risks & side effects

Limited high-quality Western trials; most human data are Russian. Reported effects are usually mild - nasal irritation, headache, occasional overstimulation or irritability.

Long-term safety data are sparse and gray-market purity is a concern.

Practical considerations

Marketed as a drug in Russia; in the US it's research-use-only and was among peptides under FDA compounding review in 2026. Commonly used intranasally.

Frequently asked questions

What is Semax used for?
In Russia, for stroke recovery and cognitive/attention disorders; in the community, for focus, memory, clarity and neuroprotection.
How does it work?
It raises BDNF, a brain growth factor that supports neuroplasticity, and modulates dopamine/serotonin - without the hormonal effects of the ACTH it's derived from.
Is Semax FDA-approved?
No - it's approved in Russia but research-use-only in the US.
Does it feel like a stimulant?
Users describe a 'clean' focus and clarity without the jitters or crash of caffeine or stimulants.
Is it safe?
Reported effects are usually mild (nasal irritation, headache), but rigorous long-term Western safety data are limited.

Legal / regulatory status

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