Semax
ACTH(4-10) fragment analogue (melanocortin-derived neuropeptide)
Status
Approved elsewhere
Registered as a drug in Russia, where it is sold as nasal drops, but not approved by the FDA or the EMA; FDA staff recommended in July 2026 that semax not be added to the US 503A compounding list, and although the advisory committee voted 8 to 5 the other way, that vote is only a recommendation and no rule has been issued.
Evidence
Preliminary
Human evidence is dominated by small Russian trials, most of them published only in Russian, and FDA's 2026 review judged the evidence insufficient for the uses it examined.
A seven-amino-acid analogue of a fragment of the hormone ACTH, registered in Russia as nasal drops for stroke and brain circulation problems and used elsewhere as an unapproved nootropic research chemical.
Structure
7 residuesPoint at a bead, or focus the chain and use the arrow keys, to name it. Pick a chemistry to highlight it.
Sequence as text
H-M-E-H-F-P-G-P-OH
What it is used for
- Cerebral ischaemia and ischaemic stroke, as a registered nasal product in Russia (approved)
- Migraine and trigeminal neuralgia (studied)
- Cognitive performance, attention and memory in healthy adults (studied)
- Optic nerve disorders, ADHD, anxiety and depression (claimed, unproven)
How it works
Semax is an analogue of the ACTH(4-7) fragment, stabilised by a Pro-Gly-Pro tail. Unlike whole ACTH it does not drive cortisol release. In rodents it binds specific sites in the basal forebrain and raises levels of brain-derived neurotrophic factor (BDNF) and its receptor TrkB, and after experimental stroke it shifts the expression of inflammatory, vascular and neurotransmitter genes. Whether any of this happens at meaningful levels in the human brain after nasal dosing has not been shown.
How strong the evidence is
Preliminary
The mechanism work is mostly rodent: Dolotov and colleagues (2006) showed specific binding and higher BDNF protein in rat basal forebrain after intranasal semax, and transcriptome studies report suppressed proinflammatory gene induction after experimental ischaemia. Russian clinical trials in stroke, cognitive decline and optic nerve disease exist but are largely published in Russian. FDA's July 2026 review excluded those reports from its assessment because English texts were unavailable and concluded there is insufficient evidence of effectiveness for cerebral ischaemia, migraine and trigeminal neuralgia; the advisory committee nonetheless voted 8 to 5 in favour of compounding eligibility.
Risks and side effects
- Not assessed for safety or quality by the FDA or the EMA, and the Russian evidence base has not been independently verified
- FDA flagged a risk of immune reactions from peptide aggregation and peptide-related impurities, especially for injected products
- Material bought as a research chemical is not pharmaceutical grade and may vary in identity, purity and sterility
- Long-term safety in humans is unstudied, including in children and pregnancy
- Not named on the 2026 WADA Prohibited List, but class S2 also captures substances structurally or biologically similar to corticotrophins, so competing athletes should not assume it is allowed
Regulatory status
Status by country
| Jurisdiction | Status | Source |
|---|---|---|
| USUnited States | No authorised medicine | Source 1 |
| EUEuropean Union | No authorised medicine | Source 7 |
| UKUnited Kingdom | No authorised medicine | Source 8 |
| AUAustralia | No authorised medicine | Source 9 |
| CACanada | No authorised medicine | Source 10 |
Timeline
Sources
- 01Semax: FDA Presentation Slides, Pharmacy Compounding Advisory Committee Meeting, July 24, 2026(opens the source in a new tab)
- 02Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks(opens the source in a new tab)
- 03FDA advisory panel narrowly rejects compounding of one peptide, backs two others(opens the source in a new tab)
- 04Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain(opens the source in a new tab)
- 05Development of Peptide Biopharmaceuticals in Russia(opens the source in a new tab)
- 06Semax (ACTH (4-7), Pro-Gly-Pro), CID 9811102(opens the source in a new tab)
- 07Find medicine: centrally authorised medicines(opens the source in a new tab)
- 08MHRA Products: active substances beginning with S(opens the source in a new tab)
- 09Australian Register of Therapeutic Goods (ARTG)(opens the source in a new tab)
- 10Unauthorized injectable peptide drugs seized and sold by Canada Peptide may pose serious health risks(opens the source in a new tab)
Educational information, not medical advice. Talk to a licensed clinician before starting, stopping or changing any medicine.