Compound hub · Semax
Semax side effects: what do studies and regulators record?
The FDA concluded that clinical information is insufficient to characterise Semax's safety (FDA briefing document, July 2026). Its review found one consumer report of eye pain and burning after a Semax product, which cannot show cause, and seven of eight tabulated human studies did not discuss adverse events, so missing reports cannot establish safety (FDA briefing document, July 2026).
When your body meets something new, it keeps a record. Your immune system notes it, your liver processes it, and a rash or a headache is a message sent back. Safety data for a compound is the same idea written down by strangers: who was given it, what was watched, and what was reported. For Semax, that written record is short, and this page shows exactly how short.
This page is part of the Semax hub. It collects adverse events recorded in trial reports, FDA documents, a TGA advisory and a seized-sample study, and names the model and the number of people each time. It gives no advice and no directions for use. The peptide side effects page covers peptides in general, and the Semax research guide covers the compound. Research material is not for human or animal use.
Key facts
| Records read | 14 October 2026 |
|---|---|
| Adverse-event reports to the FDA | One in the FDA Adverse Event Reporting System (through 3 December 2025): eye pain and burning after use of a Semax product, a single consumer report that cannot show cause (FDA briefing document, July 2026) |
| Case reports in PubMed | The FDA's searches (to 3 December 2025) did not identify any (FDA briefing document, July 2026) |
| Human studies in the FDA's table | Eight; the table below gives the size and population of each (FDA briefing document, July 2026) |
| Adverse events in those studies | In 37 adults with pain, Koroleva et al. reported no adverse events, an authors' statement rather than a safety analysis; seven other studies did not discuss events (FDA briefing document, July 2026) |
| FDA conclusion on safety | Insufficient clinical information to characterise the safety profile (FDA briefing document, July 2026) |
| Nonclinical toxicity studies the FDA did not identify | Acute, repeat-dose, developmental and reproductive toxicity, and additional genotoxicity studies (FDA briefing document, July 2026) |
| TGA advisory on unapproved peptides | Published 13 April 2026; lists adverse events received for such products as a class and does not name Semax |
| Human half-life | None found; see the half-life page |
| N-acetyl Semax amidate safety data | None found; a PubMed search on 14 October 2026 returned no record under that name |
What side effects of Semax have been recorded?
The FDA's review found one report in the FDA Adverse Event Reporting System through 3 December 2025: a consumer described eye pain and burning after using a Semax product, with hospitalisation and pain unresolved at the time of the report a year later, a single voluntary report that cannot show whether Semax caused it (FDA briefing document, July 2026). In a 1999 study of 73 patients with brain damage after oxygen shortage, EEG showed episodes of sudden abnormal brain-wave activity in some cases after Semax, an observation that does not by itself show Semax caused it, from an abstract that does not say how many patients were affected (Alekseeva et al., Anesteziologiia i Reanimatologiia, 1999).
The FDA searched PubMed to 3 December 2025 and did not identify case reports of adverse events in humans, a search result that does not rule out unreported events (FDA briefing document, July 2026). A 2005 study of 187 patients with cerebrovascular insufficiency describes Semax as having a minor percentage of side-effects and as well tolerated, including by older patients, but its abstract gives no list or counts (Gusev et al., Zhurnal Nevrologii i Psikhiatrii, 2005).
In a 1996 study of 37 adults with pain, the authors reported that no adverse events were observed, which is the authors' statement and not a safety analysis (Koroleva et al., as tabulated by the FDA, July 2026). A 1997 review by Semax's developers includes a safety statement, and its abstract gives no data and no participant numbers, so this page does not repeat it (Asmarin et al., 1997).
Evidence limits
How safe is Semax?
No regulator document or trial read for this page shows that Semax is safe. The FDA concluded in July 2026 that there is insufficient clinical information to characterise the safety profile of Semax free base or Semax acetate. Its staff were not able to find human pharmacokinetic studies, and the human safety literature it found covered a single route of use (FDA briefing document, July 2026). A lack of reported harm is different from evidence of safety, because seven of the eight studies in the FDA's table did not discuss adverse events (FDA briefing document, July 2026).
A safety claim needs a study designed to measure harm: how many people, what was watched, for how long and compared with what. The FDA notes that in several of the studies in its table Semax was given alongside other treatments, so any effect cannot be assigned to Semax alone (FDA briefing document, July 2026).
Quality adds another unknown. The FDA found that nomination packages lacked data on impurities, clumping of peptide chains (aggregation) and bacterial endotoxin, and it considered Semax free base 'not well-characterized' (FDA briefing document, July 2026). A study of seized samples found Semax and Selank in two unidentified preparations, an analytical finding about what the samples contained and not a safety result (Vanhee et al., Drug Testing and Analysis, 2020). The Russian clinical reports are described on the Semax study findings page.
What safety concerns did the FDA raise about Semax?
The FDA's July 2026 briefing document raises four safety points about Semax. It did not identify acute-toxicity, repeat-dose, developmental and reproductive toxicity, or additional genotoxicity studies (FDA briefing document, July 2026). It raised a concern about the risk of bleeding, citing antithrombotic properties of Semax discussed in one human-study reference and found in rat studies, particularly for people at risk of bleeding or taking medicines that increase bleeding risk (FDA briefing document, July 2026). It says peptides can provoke immune responses and can aggregate, and that it did not identify clinical studies of immunogenicity or aggregation for Semax (FDA briefing document, July 2026).
In mice, Semax potentiated amphetamine-induced dopamine release, a finding the FDA called concerning; its summary gives no group sizes, and this does not establish a human result (Eremin et al., 2005, as summarised in the FDA briefing document, July 2026).
The bleeding concern draws on rat work. In stressed rats given Semax, clotting measures moved toward slower clotting than in unstressed controls, an animal result that does not establish a human result, with no group count in the FDA summary, and the FDA noted that the study did not assess how the effect varies with the amount tested (FDA briefing document, July 2026, summarising Grigorjeva and Lyapina, 2010).
The FDA also says that compounded drugs carry no labelling that would adequately warn doctors and patients of such risks. The briefing document is a staff paper for an advisory committee, and its authors stated that the evaluation criteria weigh against adding Semax to the 503A Bulks List.
What have human studies of Semax recorded about safety?
In 37 adults with pain, Koroleva et al. reported no adverse events, an authors' statement rather than a safety analysis, while seven other human studies did not discuss events (FDA briefing document, July 2026, tabulating Koroleva et al., 1996). Outside that table, a 2005 study of 187 patients with cerebrovascular insufficiency describes a minor percentage of side-effects without listing them (Gusev et al., 2005), and a 1999 study of 73 patients with brain damage after oxygen shortage reports abnormal EEG episodes in some, an observation that does not by itself show cause (Alekseeva et al., 1999). The table below sets out each study.
Two studies of healthy adults, in 2018 and 2020, each list 14 volunteers, and the FDA says they may be the same people (FDA briefing document, July 2026). The FDA says the human literature it found discussed a single route of use, so its safety assessment was limited to that route (FDA briefing document, July 2026).
Is there animal toxicity data for Semax?
The FDA did not identify acute-toxicity, repeat-dose, developmental and reproductive toxicity, or additional genotoxicity studies of Semax (FDA briefing document, July 2026). The FDA did identify one long-term mouse study of female mice that already had mammary tumours, with 16 given Semax and 27 given saline, in which the Semax group had smaller tumours at the end of life and a longer mean lifespan; the FDA said the data should be read with caution because the study did not assess dose-response relationships, tested only females and had a mean treatment time under three months, in a mouse study that does not establish a human result (FDA briefing document, July 2026, summarising Meshavkin et al., 2013).
In a cell study, Semax raised the survival of mouse embryonic stem cells under serum deprivation, and the authors concluded that the peptide compounds tested did not produce a toxic effect in the embryonic and fetal period, a conclusion drawn from cell cultures with no replicate count in the abstract that does not establish a human result or whole-animal safety (Kobylyanskii et al., Bulletin of Experimental Biology and Medicine, 2017).
The FDA also says it did not identify a weight-of-evidence analysis or a nonclinical 2-year carcinogenicity study that would inform the carcinogenic potential of Semax (FDA briefing document, July 2026). The stem-cell study concerns cells in a dish and says nothing about a whole animal.
What have animal studies found about Semax and dopamine, hormones or the heart?
In a rodent study, Semax alone did not change dopamine and its breakdown products but raised the extracellular level of a serotonin metabolite, and it enhanced the dopamine release and movement caused by D-amphetamine; the abstract gives no group sizes and the results do not establish a human result (Eremin et al., Neurochemical Research, 2005). In rats, Semax changed heart rate variability at one time of day and not at another; the abstract gives no rat count, and this does not establish a human result (Arushanian et al., Eksperimental'naia i Klinicheskaia Farmakologiia, 2009).
In rats 28 days after induced heart injury, Semax reduced growth of sympathetic nerve fibres in the ventricular septum; the abstract gives no group sizes, and this does not establish a human result (Gavrilova et al., Bulletin of Experimental Biology and Medicine, 2017).
In rats assessed at 65 days of age after neonatal isolation, with groups of 13, 12 and 11 rats, Semax raised a blunted stress-induced corticosterone release to control values; this does not establish a human result (Volodina et al., Acta Naturae, 2012, full text).
No human study of Semax's effects on dopamine, hormone levels or heart rhythm was found in the sources read for this page. The Semax legal status page gives the FDA's reading of the dopamine result and the regulator position on addiction questions.
Has Semax's half-life been measured in people?
No human half-life was found in the sources read. The FDA's July 2026 review says its staff were not able to find pharmacokinetic studies of Semax in humans (FDA briefing document, July 2026). In rats given radiolabelled Semax, the peptide was in the brain by the first sample at 2 minutes and was broken down fast, a rat result from an abstract that gives no number of rats and does not establish a human result (Shevchenko et al., Russian Journal of Bioorganic Chemistry, 2006).
In a test tube with rat forebrain membranes, Semax's half-life was longer than 1 hour; the abstract gives no replicate count, and this does not establish a human result or human value (Dolotov et al., 2004). The Semax half-life page sets out the measurements found in the sources reviewed and their limits.
The sources read did not provide a human persistence or accumulation estimate, and the FDA briefing document (July 2026) reports that its search found no human pharmacokinetic studies. That gap matters for safety questions as much as for pharmacology.
What is known about the safety of N-acetyl Semax amidate?
No safety data for N-acetyl Semax amidate were found. A PubMed search on 14 October 2026 for 'N-acetyl semax', 'N-acetyl-semax' or 'Na-Semax' returned no records, and a ClinicalTrials.gov search on that date found no record for N-acetyl Semax. The nearest paper is a test-tube and cell-line study of Ac-Semax, acetylated at the amino end only, which found that acetylation did not protect human neuroblastoma cells from copper-induced toxicity, a cell-culture result about copper with no replicate count in the abstract that does not establish a human result or general compound safety (Magrì et al., Journal of Inorganic Biochemistry, 2016).
The FDA says derivatives and salts sold under the common name Semax are different substances with their own safety profiles (FDA briefing document, July 2026). Safety data for Semax therefore cannot be assumed to carry over to a modified form. The catalogue lists Semax reference material as laboratory stock, not as a medicine.
What do regulators say about the risks of unapproved peptide products?
The TGA says unapproved peptide products have not been evaluated for safety, quality or effectiveness, and that how they are made, whether they are sterile and what side effects they may cause are unknown (TGA advisory, 13 April 2026). It lists adverse events and other concerns it has received for such products as a class: severe allergic reactions needing adrenaline and hospital care, whole-body inflammation, itching, palpitations, insomnia, blurred vision and joint pain. Those reports do not name Semax, and Semax is not among the TGA's named examples.
The FDA's Semax review adds a quality point: certificates of analysis offered with the nominations lacked tests for impurities, aggregates and bacterial endotoxin (FDA briefing document, July 2026). The Semax legal status page covers how Australian regulators treat unapproved peptide products.
Comparison
Human studies of Semax and what each recorded about adverse events. Counts and adverse-event notes are from the FDA's July 2026 review unless the row names another source. Studies without a recorded count do not state one in the sources read.
| Study | People, adverse-event note and limit |
|---|---|
| Koroleva et al., 1996 | In 37 adults with pain (trigeminal neuralgia, dental plexalgia, migraine), the authors reported that no adverse events were observed; the FDA tabulated this as the authors' statement and not a safety analysis (Koroleva et al., 1996, as tabulated in the FDA briefing document, July 2026). |
| Kaplan et al., 1996 | In 19 healthy men, the FDA's table lists adverse events as not discussed, so the study gives no safety result (Kaplan et al., 1996, as tabulated in the FDA briefing document, July 2026). |
| Cherkasova et al., 2002 (meeting abstract) | In people with chronic ischemic brain disease, number not given, the FDA's table lists adverse events as not discussed; antithrombotic properties were discussed, and the meeting-abstract format limits what can be judged (Cherkasova et al., 2002, as tabulated in the FDA briefing document, July 2026). |
| Ivanikov et al., 2002 | In 32 adults with peptic ulcer given Semax alongside standard ulcer medicines, adverse events were not discussed, and the combined treatment means effects cannot be assigned to Semax alone (Ivanikov et al., 2002, as tabulated in the FDA briefing document, July 2026). |
| Aminova et al., 2016 (meeting abstract) | In 331 children with tics and Tourette syndrome, given other medicines too, adverse events were not discussed in the meeting abstract, which gave the FDA limited detail (Aminova et al., 2016, as tabulated in the FDA briefing document, July 2026). |
| Proskurina et al., 2018 (meeting abstract) | In 120 children aged 12 to 14 with depression, given other therapies too, adverse events were not discussed in the meeting abstract, which gave the FDA limited detail (Proskurina et al., 2018, as tabulated in the FDA briefing document, July 2026). |
| Lebedeva et al., 2018 and Panikratova et al., 2020 | Each study lists 14 healthy adults given Semax, the FDA says they may be the same people, and adverse events were not discussed in either (Lebedeva et al., 2018; Panikratova et al., 2020, as tabulated in the FDA briefing document, July 2026). |
| Gusev et al., 2005 (not in the FDA's table) | In 187 patients with cerebrovascular insufficiency, the abstract describes a minor percentage of side-effects and good tolerability without a list or counts (Gusev et al., 2005). |
| Alekseeva et al., 1999 (not in the FDA's table) | In 73 patients with brain damage after oxygen shortage, the abstract reports EEG episodes of sudden abnormal activity in some cases after Semax without saying how many, a timing relation that does not by itself show cause (Alekseeva et al., 1999). |
FAQ
What side effects have studies and regulators recorded for Semax?
Recorded ones are few: one consumer report of eye pain and burning to the FDA, which cannot show cause, and abnormal EEG episodes in some of 73 patients with brain damage after oxygen shortage in a 1999 study, an observation that does not by itself show cause (FDA briefing document, July 2026; Alekseeva et al., 1999). Most human studies did not report adverse events, so the list is incomplete and not evidence of safety.
Is Semax safe?
Safety has not been shown in the sources read. The FDA concluded in July 2026 that clinical information is insufficient to characterise Semax's safety profile (FDA briefing document, July 2026).
Did the FDA find case reports of harm from Semax?
The FDA's PubMed searches, run to 3 December 2025, did not identify case reports of adverse events in humans, and its adverse-event database held one consumer report, which cannot show cause (FDA briefing document, July 2026).
Has Semax been studied in children?
Yes, in two studies the FDA tabulated: 331 children with tics and Tourette syndrome and 120 children aged 12 to 14 with depression, both meeting abstracts in which Semax was given with other treatments and neither of which discussed adverse events in the information the FDA had (FDA briefing document, July 2026).
Is there a PubMed safety review of Semax?
None was found in the sources read. A PubMed search for Semax with the words adverse, safety, tolerability or side effects returned 24 records on 14 October 2026, and this page did not read all of them. The most detailed safety review in the sources read is the FDA's July 2026 briefing document. A 2026 review article covers the committee's peptide recommendations and industry safety standards in general terms, and its abstract names no Semax-specific safety data (Willis and Vu, International Journal of Pharmaceutical Compounding, 2026).
Is anything known about the side effects of N-acetyl Semax amidate?
No safety data were found. A PubMed search on 14 October 2026 returned no published study under that name, and the FDA treats derivatives sold under the name Semax as different substances (FDA briefing document, July 2026).
Does Semax interact with other medicines?
No human interaction study was found in the sources read. The FDA raised a possible bleeding-risk concern with medicines that increase bleeding risk, based on preclinical work and a meeting abstract rather than a human interaction trial (FDA briefing document, July 2026). In mice, Semax potentiated amphetamine-induced dopamine release; the FDA summary gives no group counts, and this does not establish a human result or a human interaction (Eremin et al., 2005, as summarised in the FDA briefing document, July 2026).
More in this hub
Citations
10 sourcesVolodina MA et al. Acta Naturae. 2012;4(1):86-92.
doi:10.32607/20758251-2012-4-1-86-92Vanhee C et al. Drug Testing and Analysis. 2020;12(3):371-381.
doi:10.1002/dta.2717Magrì A et al. Journal of Inorganic Biochemistry. 2016;164:59-69.
doi:10.1016/j.jinorgbio.2016.08.013Kobylyanskii AG et al. Bulletin of Experimental Biology and Medicine. 2017;163(6):731-736.
doi:10.1007/s10517-017-3891-yEremin KO et al. Neurochemical Research. 2005;30(12):1493-1500.
doi:10.1007/s11064-005-8826-8Shevchenko KV et al. Russian Journal of Bioorganic Chemistry. 2006;32(1):57-62.
doi:10.1134/s1068162006010055Dolotov OV et al. Russian Journal of Bioorganic Chemistry. 2004;30(3):213-217.
doi:10.1023/b:rubi.0000030127.46845.f0Panikratova YR et al. Doklady Biological Sciences. 2020;490(1):9-11.
doi:10.1134/S001249662001007XLebedeva IS et al. Bulletin of Experimental Biology and Medicine. 2018;165(5):653-656.
doi:10.1007/s10517-018-4234-3Grigorjeva ME, Lyapina LA Bulletin of Experimental Biology and Medicine. 2010;149(1):44-46.
doi:10.1007/s10517-010-0871-x
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Semax reference material — catalogue listingResearch use only — not for human or animal use.
Read the Semax research guideForm Laboratories supplies research-use-only reference material. This article is an educational summary of published third-party literature. It is not medical advice, not a use instruction, and research material is not for human or animal use.