The ACTH Fragment Strategy
Adrenocorticotropic hormone (ACTH) is a 39-amino-acid pituitary hormone with two distinct functional regions: residues 1-24 handle the adrenal stimulation of cortisol release, and residues 4-10 carry neurotropic activity. Isolating the neurotropic region without the adrenal region was the research premise behind Semax.
The research-grade compound is available as Semax 10mg.
Sequence: ACTH(4-10) With Modifications
Semax is Met-Glu-His-Phe-Pro-Gly-Pro — a heptapeptide that:
- Retains the ACTH(4-7) neurotropic core
- Substitutes a terminal Pro-Gly-Pro for stability
- Eliminates the adrenal-activating portion of the parent hormone
- Gains resistance to peptidase cleavage
The result is a research compound that engages neurotropic ACTH effects without triggering cortisol release.
Neurotrophic Factor Research
The most characterized Semax effects involve endogenous neurotrophic factor modulation:
- BDNF (Brain-Derived Neurotrophic Factor): Upregulation in hippocampal tissue
- NGF (Nerve Growth Factor): Increased expression in cortical regions
- TrkB receptor signaling: Downstream of BDNF effects
Elevating endogenous neurotrophic signaling is the proposed mechanism behind the cognitive and neuroprotective findings in the Russian literature.
Melanocortin Receptor Interactions
Semax retains the histidine-phenylalanine core of ACTH(4-10) — the region responsible for melanocortin receptor binding. Research suggests modest MC4R activity, which contributes to:
- Cognitive enhancement observations
- Modulation of stress-axis signaling (paradoxically, given the ACTH origin)
- Interaction with dopaminergic systems
Russian Research Context
Much of the foundational Semax literature is Russian-language, dating to the 1980s-1990s. The compound was developed at the Institute of Molecular Genetics and tested extensively in stroke recovery, cognitive enhancement, and optic nerve protection contexts. Western research builds on this foundation but is less extensive.
Plain Semax vs N-Acetyl Semax Amidate
Two Semax research compounds exist:
- Plain Semax: Original heptapeptide, shorter half-life
- N-Acetyl Semax Amidate (NA-Semax): Modified for stability and intranasal delivery, longer duration
Plain Semax matches the original Russian protocols; NA-Semax is the modern optimized research form. Choice depends on whether the research replicates foundational work or extends it with improved pharmacokinetics.
See Semax 10mg for the standard research vial.