Semax

Definition

Semax is a synthetic heptapeptide built from the ACTH(4–7) fragment of adrenocorticotropic hormone with a proline-glycine-proline tail added for stability. It was developed in Moscow in the 1980s and is a registered prescription drug in Russia, given as a nasal spray for stroke recovery and cognitive complaints.

That registration is the molecule's defining fact and its defining asterisk: Semax has never been reviewed by FDA, and a drug approved abroad holds no US marketing status of any kind.

Evidence

The mechanistic literature is real: Semax raises brain-derived neurotrophic factor and trkB receptor expression in rat hippocampus ^[1] and binds brain tissue with measurable specificity ^[2]. The clinical literature, by contrast, lives almost entirely in Russian-language journals — a representative modern example followed 110 post-stroke patients through rehabilitation with Semax, tracking plasma BDNF and functional scores ^[3].

None of this record has passed through FDA review, and no English-language randomized trial supports a cognitive-enhancement use. The nootropic market sells the compound on the Russian dossier's reputation rather than on evidence an American regulator has examined.

Lawful access

Semax was removed from Category 2 of the interim 503A bulks list in April 2026 without Category 1 listing. In July 2026 the Pharmacy Compounding Advisory Committee voted 8–5, with one abstention, to recommend adding it to the section 503A list. The vote is advisory; no FDA final rule has issued, and no licensed pharmacy may lawfully compound Semax as of August 2026.

Nasal sprays and vials sold to US buyers today are research-use-only or gray-market imports, outside pharmacy oversight; the pending page tracks the rulemaking that could change the compounding question.

Related molecules

The index files Semax with the neuropeptides alongside DSIP, which met the opposite fate at the same July 2026 meeting — the panel's only vote against a listing; read together, the two records show the committee weighing evidence rather than waving a class through. The molecule index holds the full table.