Semax Research in the US: An ACTH(4-10) Analog After the 2026 PCAC Vote

• ·Semax is a synthetic heptapeptide: the ACTH(4-7) fragment Met-Glu-His-Phe joined to a Pro-Gly-Pro tail that slows enzymatic breakdown.
• ·It was developed in Russia, where it is registered as a medicine. It is not approved in the US.
• ·The best-cited mechanistic work reports that Semax increases BDNF and TrkB expression in the rat hippocampus.[1]
• ·On 24 July 2026 the FDA's Pharmacy Compounding Advisory Committee (PCAC) voted 8 in favor, 5 against, with 1 abstention, to recommend Semax for the 503A bulks list. The vote is advisory.[3]

ACTH (adrenocorticotropic hormone) is a 39-residue pituitary hormone. Short ACTH fragments, especially within the 4-10 region, were found decades ago to affect learning and attention in animal models without stimulating the adrenal cortex. Semax was designed to keep that central activity while improving stability: the Pro-Gly-Pro extension makes it more resistant to peptidases than ACTH(4-10) itself.

• ·Sequence. Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP).
• ·Length. 7 residues.
• ·Derived from. ACTH(4-7) plus a C-terminal Pro-Gly-Pro extension.
• ·Molecular weight. 813.9 g/mol, C₃₇H₅₁N₉O₁₀S (PubChem CID 9811102).
• ·Notable feature. No corticotropic (adrenal-stimulating) activity.

Research Material

Amino Acid Sequence

Chemical Structure

Dolotov and colleagues reported in Brain Research (2006) that Semax regulated the expression of brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the rat hippocampus. After a single intranasal application, they measured higher BDNF protein, increased TrkB phosphorylation, and raised BDNF and TrkB mRNA.[1] BDNF-TrkB signaling is central to synaptic plasticity, which is why this finding is the most cited mechanistic anchor for Semax.

Much of the literature comes from Russian research groups, and some of it is published in Russian-language journals, which makes systematic review harder for English-speaking labs. Other reported research directions include:

• ·Ischemia models, reflecting the compound's clinical use in Russia.
• ·Gene-expression studies in rodent brain after ischemic injury, including a genome-wide transcriptional analysis in a rat model of focal ischemia.[2]
• ·Melanocortin receptor interactions, given its ACTH origin, though the receptor basis of its central effects is not settled.

• ·Receptor target. No single receptor has been established as the primary mediator.
• ·Independent replication. Replication outside the originating groups is limited.
• ·Route and delivery. Many studies use intranasal administration in animals, so brain exposure by route is a methodological question in its own right.
• ·Western clinical data. These are sparse.

Semax was among the twelve peptides removed from the FDA's Category 2 list in April 2026.[4] Removal from Category 2 did not, by itself, confer any compounding status.[3]

On 23 and 24 July 2026 the FDA's Pharmacy Compounding Advisory Committee reviewed Semax (free base and acetate) for inclusion on the Section 503A Bulk Drug Substances List, alongside BPC-157, KPV, TB-500, MOTS-c, Epitalon and Semax. FDA staff had recommended against inclusion for every substance under review, citing insufficient characterization, little or no human effectiveness evidence, and inadequate human safety data. The committee voted in favor anyway. The vote was 8 in favor, 5 against, 1 abstention.[3][5][6]

Semax was heard on the second day of the meeting, 24 July.[3] It remains unapproved for any use in the US, it does not appear in 21 CFR 216.23,[7] and the FDA would still have to complete rulemaking before anything changed for compounding pharmacies. Our PCAC breakdown covers all seven substances reviewed, and the April 2026 Category 2 removals have their own post. What the vote does not do:

• ·It is non-binding. The committee advises, it does not decide. No final FDA determination has been issued and none of the six peptides appears in 21 CFR 216.23.
• ·It requires a further step. Addition to the 503A Bulks List requires formal action by the Secretary of Health and Human Services, which had not occurred as of publication.
• ·It does not make the compound an FDA-approved drug, and it establishes nothing about efficacy.
• ·It does not legitimize research-chemical retail. A compounding-list decision concerns licensed pharmacists preparing patient-specific prescriptions under Section 503A, which is a different channel entirely from research material sold in vials.

Semax contains methionine, which is prone to oxidation. Store lyophilized material frozen and dry, aliquot reconstituted solutions, and avoid repeated freeze-thaw cycles. See shipping and storage for lyophilized peptides; the aliquot and cold-storage planner in the Peptide Calculator helps split a stock before it goes into the freezer.

Each Semax lot is tested by Janoshik Analytical before sale, and the certificate is published as the laboratory reported it, verifiable on Janoshik's own site. The current certificate is below. HPLC purity and measured content are reported as separate numbers because they answer separate questions. Every lot is listed on the certificates of analysis page.

Published Certificate

Batch

SEM-CA-26A-01

Purity (HPLC)

99.566%

Measured content

11.69 mglabeled 10 mg

Laboratory

Janoshik

Verify on the lab’s own databaseAll published certificates

Available at Eppix Labs

Semax

10mg

Every batch tested by an independent laboratory, with the certificate published before sale.

From $25.99 USDIn stock