Semax nasal spray: what the intranasal studies show

The short answer: semax nasal spray is the form semax was designed for. The drug was developed in Moscow as intranasal drops, and every human study of semax we could find in PubMed used the nose. [1] Those studies are small, open label, published in Russian, and run by the group that created the drug, so they suggest effects in stroke and optic nerve disease without proving them. [2] In the United States, semax is not an approved drug, and the July 2026 advisory committee vote in its favor has not yet become a rule. [14]

This explainer covers what the intranasal research measured and what the legal picture means. It does not give dosing or administration instructions. For the full evidence record, see the semax entity page.

What is semax nasal spray?

Semax is a seven amino acid fragment of the stress hormone ACTH with a Pro-Gly-Pro tail added for stability. Its developers describe it as one of the rare regulatory peptides that went from basic research into clinical use in Russia, where it is given intranasally. [1] The research-use sprays sold online borrow that route, but they are not the Russian registered product and are not approved in the United States in any form. Searches for "semax spray", "nasal semax" and "intranasal semax" all point at the same thing: the peptide delivered through the nose.

Why is semax given as nasal drops?

Two findings from the developing institute explain the choice of route.

First, semax reaches the brain quickly through the nose. In rats given radiolabeled semax intranasally, about 0.093% of the dose per gram of tissue was found in the brain two minutes later, and 80% of that radioactivity was still intact semax. [5]

Second, semax breaks down fast once it is in the body. The same rat study found rapid enzymatic degradation, with the Pro-Gly-Pro fragment dominating in blood and tissue samples. [5] A later study tested how semax and shorter glyprolines held up against enzymes from nasal mucus, brain membranes and rat blood, and found semax was cleaved to a shorter His-Phe-Pro-Gly-Pro fragment. [8]

Put together, the rationale is a short path to the brain for a peptide that does not survive long in circulation. That is a pharmacology argument from rodents. It has not been confirmed with human brain measurements.

What did the intranasal semax trials measure?

Every human efficacy study we found used intranasal semax on top of standard care, compared with standard care alone.

• Acute ischemic stroke (1997). Patients in the acute period of hemispheric stroke who received intranasal semax with standard therapy showed faster regression of neurological deficit and better EEG measures than patients on standard therapy alone. The study was open, not blinded, and had no placebo. [2]
• Chronic cerebrovascular insufficiency (2005). Courses of semax were associated with fewer exacerbations and slower progression over follow-up, again in an open comparison. [4]
• Stroke across stages (2018). The same research group reported better functional recovery when semax was added at different stages of ischemic stroke. [9]
• Optic nerve disease (2000). Patients with several types of optic nerve disease received semax as nasal drops or by endonasal electrophoresis alongside standard treatment, and the authors reported better visual acuity, visual fields and nerve conduction than controls. [3]

There is also one imaging study in healthy adults. Twenty-four volunteers had resting-state brain scans before and 5 and 20 minutes after intranasal semax (14 people) or placebo (10 people), and the semax group showed changes in the default mode network. [10] A change on a brain scan is not a change in memory, focus or mood, and this study did not measure those outcomes.

What is missing matters more than what is there. There is no double-blind, placebo-controlled semax trial described in an indexed English-language report, no independent replication outside the developing network, and no controlled study of semax as a nootropic in healthy people. That is why our semax evidence grade is human observational rather than randomized. The stroke recovery page and the cognitive decline page set these findings beside treatments with stronger evidence. Our guide to reading a peptide study explains why open-label, single-group research carries so much less weight.

Semax nasal spray vs injections: what does the data show?

Searches for "semax injections" usually come from products sold as injectable powders. The comparison rests on animal work alone.

In a rat study that gave semax by both routes, intranasal semax improved learning in a passive avoidance task at lower doses than intraperitoneal injection. Injection, however, reduced pain sensitivity, and the nasal route did not. The authors concluded that the two effects probably run through different brain structures. [7]

The rodent mechanism work that underpins the cognitive claims also used the nose: a single intranasal dose raised hippocampal BDNF protein and its trkB receptor within hours. [6] No human study has compared nasal and injected semax, and injected semax has no published human data at all.

Is semax nasal spray legal? What the PCAC recommendation means

Semax has moved through three regulatory stages in three years.

1. Category 2. FDA placed semax on its 503A Category 2 list of bulk substances that may present significant safety risks in 2023, and removed it from that list in April 2026. [12]
2. Advisory vote. On July 23 to 24, 2026, the Pharmacy Compounding Advisory Committee recommended adding semax to the 503A bulks list. [14] The committee advises FDA; its vote does not change the law.
3. Final rule pending. Semax is not on the 503A bulks list today. [13] Until FDA publishes a final rule, a 503A pharmacy has no federal basis to compound it from bulk, and state pharmacy boards cannot authorize what federal law does not.

If a final rule lists semax, a licensed prescriber could order it from a 503A pharmacy for an individual patient. It would still not be an FDA approved drug, and the rule would not make research-labeled sprays lawful for human use. The semax regulatory tracker logs each dated step, the PCAC vote explainer covers the meeting, and the legal hub covers state rules. For how prescribing works once a substance is listed, see how to get peptides prescribed. Our explainer on what peptide therapy is covers how clinics use the term.

Because there is no lawful compounded product yet, there is no comparable price. The semax cost page explains why advertised prices are not a benchmark.

Semax nasal spray side effects and safety

No blinded safety trial exists. The developers wrote in 1997 that semax produced no negative side effects or complications in their clinical experience. [1] That is a claim from the team that created the drug, based on uncontrolled use, not a systematic safety review. Our entity record lists nasal irritation as the most common complaint and anecdotal reports of anxiety, irritability or poor sleep, none confirmed by a controlled study.

Product quality is a separate risk. When a Belgian medicines laboratory analyzed two seized preparations in 2017 and 2018, it found semax and selank, noted that these peptides had not completed clinical trials, and found them freely sold online as injectable powders and nasal sprays. [11] A research-labeled spray has no verified identity, purity, sterility or strength.

For athletes, semax is not named on the WADA Prohibited List, and its status under the non-approved substances section is unclear because it is registered in Russia. [15]

Semax nasal spray vs selank nasal spray

Semax and selank are often sold side by side as sprays, and many people search for them together. They are different molecules with different evidence: semax was studied mainly in stroke, selank mainly in anxiety. Semax was part of the July 2026 recommendation and selank was not. The semax vs selank comparison owns the head-to-head. The selank nasal spray explainer covers the combination question, and our post on N-acetyl semax and selank amidate covers the modified versions sold online.

The bottom line

Semax nasal spray is the route with the most research behind it, but that research is a handful of open-label Russian studies and rodent pharmacology. It has no controlled trial in healthy adults and no approval in the United States. The July 2026 vote opened a possible compounding path; it did not open one yet. We will update this page when FDA publishes a final rule.