Semax peptide

Summary

Semax is a seven amino acid fragment of the stress hormone ACTH, modified to have no hormonal activity, developed in Moscow and registered in Russia as nasal drops for stroke, cognitive impairment, and optic nerve disease. Rodent studies show it raises BDNF (a protein that supports nerve cell growth) and its receptor in the hippocampus, the brain's memory center, and Russian clinical studies from the 1990s onward report better recovery after ischemic stroke (stroke from a blocked artery), but those trials are open label (everyone knew who was treated), published in Russian, and not independently replicated. FDA removed it from the 503A Category 2 list (compounding ingredients flagged for significant safety risks) in April 2026 and the Pharmacy Compounding Advisory Committee (FDA's outside expert panel) recommended it for the 503A bulks list (ingredients pharmacies may use to compound drugs for individual patients) in July 2026; no final rule has been published.

What is Semax?

Semax is a synthetic heptapeptide analog of ACTH fragment 4-10 (Met-Glu-His-Phe-Pro-Gly-Pro), a melanocortin derived nootropic and neuroprotective peptide. It is also known as Met-Glu-His-Phe-Pro-Gly-Pro, ACTH(4-7)-Pro-Gly-Pro, Semax 0.1% and 1% nasal drops, N-acetyl Semax and NA-Semax amidate (unstudied analogs), Semax peptide, Semax nasal spray, Semax nasal drops.

How does it work?

Semax is derived from ACTH(4-10) with a C-terminal Pro-Gly-Pro that protects it from breakdown. It does not stimulate cortisol release. In rat hippocampus a single intranasal dose increased BDNF protein and trkB receptor expression within hours, and rodent work also shows effects on the serotonergic and dopaminergic systems, reduced nitric oxide production after ischemia, and increased expression of neurotrophic and immune genes. Intranasal delivery is proposed to reach the brain along olfactory pathways. Human mechanistic data are limited.

Semax benefits: what the evidence shows

Human evidence consists of Russian clinical trials that are open label or poorly described, published in Russian language journals. Gusev et al. 1997 reported faster neurological recovery and lower mortality in acute hemispheric ischemic stroke patients given intranasal semax alongside standard care compared with controls. Gusev et al. 2005 reported fewer exacerbations in chronic cerebrovascular insufficiency, and Gusev et al. 2018 reported benefits at several stages of ischemic stroke. None used a placebo controlled double blind design described in an indexed English language report, and none have independent replication. Animal data on BDNF induction are more rigorous. PeptideAgent grades the evidence human observational.

Human evidence

Gusev 1997: patients in the acute period of hemispheric ischemic stroke received intranasal semax (12 to 18 mg per day) with standard therapy; the authors report faster regression of neurological deficit and improved EEG parameters versus standard therapy alone. Gusev 2005: patients with chronic cerebrovascular insufficiency treated with semax courses had fewer exacerbations over follow up. Gusev 2018: an analysis across stages of ischemic stroke reporting improved functional outcomes. These are open comparative studies without blinding or placebo, from the developing research group.

Animal evidence

Dolotov et al. 2006: intranasal semax in rats increased hippocampal BDNF protein about 1.4 fold and trkB expression within hours of a single dose. Other rodent studies from the Institute of Molecular Genetics report reduced infarct volume after focal ischemia, changes in expression of hundreds of genes involved in inflammation and neurotransmission, and improved learning in behavioral tests.

Key studies

Conditions studied

Is Semax legal in the United States?

FDA and compounding status

Semax was placed on the FDA 503A Category 2 list (substances with significant safety risks) in 2023 and removed from it on April 15, 2026. On July 23 to 24, 2026 the Pharmacy Compounding Advisory Committee recommended adding semax to the 503A bulks list. As of the last verification date FDA has not published a final rule, so compounding pharmacies and state boards vary in whether they will fill it. It is not an FDA approved drug and is not eligible for 503B outsourcing. It is a registered prescription drug in Russia.

WADA status

WADA status unclear. The current prohibited list does not name this compound explicitly and its class status is not settled. Athletes should ask their anti-doping organization before use.

Regulatory timeline

1. Jul 23, 2026PCAC

   PCAC recommends six peptides for the 503A bulks list

   At its July 23 to 24, 2026 meeting, FDA's Pharmacy Compounding Advisory Committee voted to recommend that BPC-157, KPV, TB-500, MOTS-c, semax, and epitalon be added to the 503A bulk drug substances list. A committee recommendation is advisory; FDA must still issue a rule before the substances are formally listed.

   Regulatory: Under FDA reviewSource: Pharmacy Compounding Advisory Committee
2. Apr 15, 2026FDA

   FDA lists BPC-157 and 16 other peptides as withdrawn from 503A Category 2

   FDA's Category 2 page, revised in April 2026 and current as of April 22, 2026, moved BPC-157, AOD-9604, CJC-1295, dihexa, DSIP, epitalon, injectable GHK-Cu, ipamorelin, KPV, LL-37, melanotan II, MOTS-c, PEG-MGF, selank, semax, thymosin alpha-1, and thymosin beta-4 fragment (TB-500) to a list of bulk drug substances nominated but withdrawn by their nominators. A withdrawn substance is no longer in 503A Category 2, but withdrawal is not an approval and does not place a substance on the 503A bulks list; a 503A pharmacy still needs a listing before it may compound it. Ipamorelin acetate remains in 503B Category 2. Seven of the withdrawn peptides (BPC-157, KPV, TB-500, MOTS-c, semax, epitalon, and DSIP) were taken to the Pharmacy Compounding Advisory Committee in July 2026.

   Regulatory: Removed from Category 2 (Apr 2026)Source: FDA: Certain bulk drug substances for use in compounding may present significant safety risks (503A and 503B Category 2 lists and withdrawn nominations, content current as of April 22, 2026)
3. Sep 2023FDA

   FDA places a batch of nominated peptides in 503A Category 2

   In September 2023 FDA updated its 503A bulk drug substances category lists to place a group of nominated peptides in Category 2, which means FDA identified significant safety risks and the substances may not be used in 503A compounding while the evaluation continues. Kisspeptin-10 and ibutamoren (MK-677) were added on September 29, 2023 and remain in Category 2 on the FDA page current as of April 22, 2026. BPC-157, CJC-1295, ipamorelin, AOD-9604, dihexa, DSIP, epitalon, KPV, MOTS-c, selank, semax, melanotan II, LL-37, thymosin alpha-1, and thymosin beta-4 fragment (TB-500) were also placed in Category 2 under the 503A interim policy; that same page now lists them as nominated but withdrawn (see the April 2026 event). Hexarelin, PNC-27, and 5-amino-1MQ have never appeared on the FDA category lists.

   Regulatory: Not eligible for compoundingSource: FDA: Certain bulk drug substances for use in compounding may present significant safety risks (503A and 503B Category 2 lists and withdrawn nominations, content current as of April 22, 2026)

Full tracker for Semax or the category-wide tracker.

What published studies of Semax used

Ranges below are reported from published studies and labeling only. PeptideAgent does not recommend doses or protocols.

Russian stroke studies used intranasal semax 12 to 18 mg per day (1% solution) for 5 to 10 days in acute ischemic stroke, and lower doses of the 0.1% solution (roughly 0.2 to 2 mg per day) for cognitive and asthenic indications, according to Russian labeling and open label reports. No dose finding trial has been published in an indexed English language journal.

Routes reported

Semax side effects

Side effects

Interactions

Contraindications

How do people access Semax legally?

Typical cost: No lawful compounded price: Semax is not on the 503A bulks list, and PCAC's July 2026 recommendation is advisory until FDA publishes a final rule. Advertised clinic prices are not a comparable price. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity.

• Semax cost by channel
• Rules by state
• Verified provider directory

Compare Semax

• Cerebrolysin vs Semax
• Dihexa vs Semax
• Semax vs Noopept
• Semax vs Selank

What's actually offered, and what that means for you

Licensed compounding pharmacies, clinics, and telehealth prescribers openly offer many unapproved peptides, and prescribers write prescriptions for them. That does not make semax lawful. FDA's advisory committee recommended semax for the 503A bulks list in July 2026, but FDA has not published a final rule, so a pharmacy has no federal basis to compound it yet. [5] [6]

Enforcement is uneven. FDA mostly acts through warning letters to compounders and online sellers, Category 2 safety listings, and import alerts that let it detain shipments, rather than stopping every pharmacy. State pharmacy boards oversee pharmacies day to day, and their rules differ. [9] [10] [11] [12] [13]

What changes for you

• No FDA review of the product: FDA does not check a compounded drug's safety, effectiveness, or quality before it is sold. [13]
• Identity, purity, sterility, and dose accuracy can vary from batch to batch. [11]
• Insurance rarely covers it, so you usually pay cash.
• For tested athletes, WADA status is unclear; ask your anti-doping organization before any use. [7]

What to check

These checks lower some risks, but they do not make an unlawfully compounded product lawful or safe. Check for:

• A 503A pharmacy licensed in your state (your state board of pharmacy publishes license lookups). [13]
• A real evaluation by a licensed prescriber, not just an online form.
• A certificate of analysis for the specific batch.

Frequently asked questions

Decisions about starting, stopping, or combining any treatment belong with a licensed clinician who knows your history.

From the blog

• N-acetyl semax and selank amidate: is there any human data?

  What N-terminal acetylation and C-terminal amidation are claimed to change in semax and selank, what the lab studies actually found, and why no human study has tested either modified version.

• Semax nasal spray: what the intranasal studies show

  Semax was developed in Russia as nasal drops. What the intranasal stroke and imaging studies measured, how nasal and injected data compare, and what the July 2026 PCAC vote means.

• BPC-157 nasal spray: what is and is not known about intranasal use

  No published study has given BPC-157 as a nasal spray to animals or people. What the one nose-related rat study tested, what a nasal peptide must prove, and its legal status.

• Selank nasal spray: the evidence, and combining it with semax

  What the intranasal selank studies measured, whether the route matters, and what is known about semax and selank nasal spray together: no trial has tested the combination.

• How to read a peptide study

  A practical checklist for judging peptide research: who was studied, how it was designed, what was measured, and whether it was replicated. Worked through with real studies.

• PCAC recommended six peptides. What changes and what does not

  FDA's compounding advisory committee backed BPC-157, KPV, TB-500, MOTS-c, semax, and epitalon for the 503A bulks list and rejected DSIP. Here is what the vote does and does not do.

Sources

Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.