Semax peptide

Semax is a synthetic peptide of seven amino acids (Met-Glu-His-Phe-Pro-Gly-Pro). It is an analog of a fragment of adrenocorticotropic hormone (ACTH 4-10), developed in Russia and studied mainly as a nasal preparation [2] [5]. In the US it is sold online as a nootropic, a compound taken to improve focus and memory.

The research behind it is mostly Russian: rodent studies on brain-derived neurotrophic factor (BDNF) [2], and small clinical studies in stroke, motor neuron disease and optic-nerve disease, published in Russian-language journals [3] [4] [5]. None tests semax as a cognitive enhancer in healthy people. Under a draft HHS enforcement policy announced October 28, 2026, HHS says it does not intend to take action against 503A pharmacies and physicians that compound semax under ten conditions, for intranasal use only [1]. It remains unapproved by the FDA.

Semax is not FDA-approved for any use. On October 28, 2026, HHS announced a draft, interim enforcement-discretion policy, which is not final and not binding on HHS or the public (comments are open until November 13, 2026): while FDA decides through rulemaking whether semax belongs on the 503A bulk drug substances list, HHS does not intend to take action against a State-licensed pharmacy, Federal facility, or licensed physician that compounds semax when ten conditions are all met [1]. The policy states that compounded drugs are not FDA-approved and that FDA does not review their safety, effectiveness, or quality.

Route limits: the policy covers semax free base for intranasal use only [1]. Injectable semax, which is widely sold online as a powder for reconstitution, falls outside it. Note that the policy names the free base, while the other five Appendix A peptides are named as acetate salts. The policy also names a 510(k)-cleared syringe as the only device that may be packaged with or contain the product and does not mention nasal spray pumps, so how a pharmacy may dispense semax spray under it is not yet clear [1].

The other conditions include a patient-specific prescription; bulk peptide from an FDA-registered manufacturer with a certificate of analysis covering identity, purity, potency, endotoxin, heavy metals, microbial limits and impurities; a single active ingredient per product (so no semax and selank combination sprays); the label statement "This is a compounded drug product. Not for resale."; and reporting of serious adverse events and quality problems to FDA MedWatch and the states [1].

History: semax was in FDA's Category 2 from September 29, 2023 until April 22, 2026. CDER recommended against listing it and the Pharmacy Compounding Advisory Committee voted in favor [1]. HHS cited new certificates of analysis that supply the endotoxin result CDER called the main gap, documented use, and its reading that CDER's concerns were mechanistic, noting that the intranasal human record CDER compiled covers several hundred subjects with no reported adverse outcome [1]. An independent analysis of the advisory committee review appears in the compounding literature [7].

The main proposed mechanism is BDNF, a growth factor that supports neuron survival and learning. In rats, a single dose of semax (50 micrograms per kilogram) produced a maximal 1.4-fold increase in hippocampal BDNF protein, a 1.6-fold increase in phosphorylation of its receptor trkB, and 3-fold and 2-fold increases in BDNF and trkB mRNA, along with more conditioned avoidance responses, a learning measure [2].

Whether those rodent BDNF changes translate into meaningful cognitive effects in people has not been established. No study we found measured memory or attention in healthy adults given semax.

Stroke: a Russian study of 110 patients after ischemic stroke compared those who received semax with those who did not, across early and late rehabilitation groups. Semax raised plasma BDNF, which stayed high throughout the study, and semax with high BDNF was associated with faster and better recovery on the Barthel index of daily functioning [3]. The abstract does not describe randomization or blinding, so it reads as an add-on comparison rather than a placebo-controlled trial.

Motor neuron disease: in an open-label study of 27 patients, intranasal semax did not change the course of nerve damage or the clinical scores, but improved overall quality of life through better emotional state and motivation, with the largest effect on day 10 [4]. Optic-nerve disease: a three-group study added semax by nasal drops or by endonasal electrophoresis to standard treatment and reported better visual acuity, visual field and color vision than in controls [5].

Evidence grade: D. These are small studies, published in Russian, mostly open-label or add-on designs, and none has been reproduced outside Russia. None of them studied healthy people taking semax to improve focus or memory, which is how it is marketed in the US.

There is no US labeled dose and no dose validated for nootropic use. For context only, the Russian clinical studies used specific regimens in sick patients: the motor neuron disease study gave 12 mg a day of a 1% solution intranasally in two 10-day courses two weeks apart [4], and the stroke study gave 6,000 micrograms a day in two 10-day courses 20 days apart [3]. Those are study protocols for stroke and neurodegenerative disease, not a dose for a healthy adult, and they do not transfer to a US compounded spray of unverified concentration.

Under the draft HHS policy, compounded semax is a nasal product prescribed for one patient, although the policy's device condition does not mention spray pumps. The strength and schedule are the prescriber's decision.

HHS's justification describes the intranasal human record compiled by CDER as several hundred subjects with no reported adverse outcome, and says the bleeding and abuse-potential concerns CDER raised have no clinical counterpart in that record [1]. That record is short-term and comes from studies in patients, not from long-term use by healthy people, so the long-term safety of repeated use is unknown.

Quality is the clearer risk in the research-chemical market. Belgian regulatory chemists found semax and selank in seized preparations and noted that such nootropic research peptides are sold freely online as injectable powders and nasal sprays [6]. A product compounded under the HHS policy must come from a registered manufacturer with a lot-level certificate of analysis and contain semax alone [1].