ACTH Fragment (4-10)
Nootropic / Neuropeptide FragmentresearchAlso known as: ACTH(4-10), Semax precursor fragment, Org 2766, MSH/ACTH 4-10, MEHFRWG
A heptapeptide fragment of adrenocorticotropic hormone that enhances memory, attention, and learning without the adrenal-stimulating effects of full-length ACTH, serving as the basis for nootropic peptides like Semax.
Overview
ACTH(4-10) is a seven-amino acid fragment (Met-Glu-His-Phe-Arg-Trp-Gly) derived from the core active sequence of adrenocorticotropic hormone (ACTH). While full-length ACTH (39 amino acids) primarily stimulates cortisol release from the adrenal glands, the 4-10 fragment retains the neurotrophic and cognitive-enhancing properties without significant adrenal stimulation. This fragment was identified in the 1970s-80s as the minimal sequence responsible for ACTH's effects on learning and memory. It served as the structural basis for the development of Semax (a modified ACTH 4-10 with a Pro-Gly-Pro tail for stability) and Org 2766 (a synthetic analogue used in clinical trials). Research has shown ACTH(4-10) improves attention, visual memory, and motivation in both animal models and human studies. It modulates dopaminergic and noradrenergic neurotransmission and has neurotrophic effects including promotion of BDNF expression.
Mechanism of Action
ACTH(4-10) acts through melanocortin receptors (primarily MC3R and MC4R) in the brain, distinct from the MC2R that mediates adrenal cortisol release. Its mechanism includes: (1) Enhancement of catecholaminergic (dopamine and norepinephrine) neurotransmission in prefrontal cortex and hippocampus; (2) Promotion of BDNF and NGF expression, supporting neuroplasticity and neuronal survival; (3) Modulation of acetylcholine release in memory-critical brain regions; (4) Enhancement of long-term potentiation (LTP) in hippocampal circuits; (5) Improvement of attention and arousal through effects on the reticular activating system. The fragment does not significantly bind MC2R, explaining its lack of cortisol-stimulating activity.
Molecular Formula
C40H54N10O8S
Molecular Weight
838.98 g/mol
Sequence
Met-Glu-His-Phe-Arg-Trp-Gly
Dosage Protocols
Dose Range
250mcg – 1000mcg
Frequency
Once or twice daily
Route
subcutaneous
Cycle Length
4-8 weeks
Limited established protocols. Many users opt for Semax (modified ACTH 4-10 with better stability) instead. Intranasal administration may also be effective.
Source: Research literature and community protocols
🧮 Personalized Dosage Calculator
💰 Estimated Pricing
Typical Supply
10mg vial
Last Updated
2026-02
ACTH fragment peptide. Research chemical pricing only. Limited commercial sources.
⚠️ Prices are estimates based on publicly available data and may vary significantly by vendor, location, and prescription status. This is not medical or financial advice.
Side Effects
| Effect | Severity |
|---|---|
| Headache | mild |
| Irritability | mild |
| Nasal irritation | mild |
| Insomnia | mild |
Pros & Cons
Retains the cognitive-enhancing properties of ACTH without adrenal stimulation or cortisol increase
Foundation peptide for Semax — one of the most well-studied nootropic peptides
Multiple human studies supporting effects on attention, memory, and learning
Good safety profile with minimal side effects at standard doses
Short half-life — the parent fragment is rapidly degraded, which is why Semax was developed
Most users are better served by Semax, which has superior stability and more clinical data
Limited commercial availability compared to Semax
Research Studies
🩸 Blood Work
No specific bloodwork requirements reported for this peptide. General health panels are always recommended before starting any peptide protocol.
Legal Status
Available as a research peptide. Not FDA-approved. The derivative Org 2766 was tested in clinical trials. Semax (modified ACTH 4-10) is an approved drug in Russia. Unscheduled in most countries.
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