Emoxypine (Mexidol), an Antioxidant Paired with Succinate, Action

In Russia, emoxypine has been a prescription medicine for decades, with its own randomised placebo-controlled trials, meta-analyses and a place on national essential medicines lists. In PubMed, the English-language clinical reports on it can be counted on one hand, and in the EMA and FDA registers it does not appear at all. That gap explains why the same compound is prescribed by neurologists in one country and sits in a catalogue as a research reagent in another.

This article sets out what is known about emoxypine: where it came from, how it acts in the cell, what animal models and the Russian patient trials showed, how to read that body of evidence, and what its status is in the EU, the United States and in sport. There is nothing here about doses, and the FAQ at the end explains why.

In our catalogue, the compounds discussed in this article are chemical reagents intended solely for laboratory research (Research Use Only). They are not medicinal products, dietary supplements or foods, and they are not intended for use in humans or animals. What this status means is explained in our material on the legal status of research reagents.

An essential distinction: the clinical trial results described below concern the medicine Mexidol®, which is prescription-only in Russia and is given under medical supervision in hospitals and outpatient clinics. Research material containing the same substance is not a substitute for a medicinal product and does not replace medical consultation. The clinical trial findings do not apply to it.

What emoxypine is

Chemically it is 2-ethyl-6-methyl-3-hydroxypyridine: a pyridine ring carrying a hydroxyl group, the same scaffold found in pyridoxine, one of the forms of vitamin B6. The formula is C₈H₁₁NO and the mass 137.2 g/mol (PubChem CID 114681). In the medicine and in catalogues it mostly appears as a salt with succinic acid, ethylmethylhydroxypyridine succinate, C₁₂H₁₇NO₅, 255.3 g/mol (PubChem CID 122298). The difference between base and salt matters when reading a certificate of analysis, because the same weighed amount contains a different number of molecules of the pyridine fragment.

The compound was developed in the Soviet Union as a synthetic antioxidant and entered Russian pharmacotherapy under the trade name Mexidol®. A 2012 review describes it as a medicine with “a broad spectrum of pharmacological effects” (Voronina, 2012, PMID 23461005), and the only extensive English-language review stresses its kinship with pyridoxine, its ability as a small molecule to cross the blood–brain barrier, and the iron-chelating property observed in vitro (Gupta et al., 2022, PMID 35992374). A PubMed query for emoxypine, emoxipine and Mexidol returns 443 records (as of 3 November 2026), most of them in Russian.

Mechanism: antioxidant, succinate and receptors

The Russian literature describes the mechanism in three layers. The first is direct antioxidant action: the phenolic hydroxyl group donates a hydrogen atom to radicals, which breaks the chain of lipid peroxidation in membranes. In vitro, emoxypine inactivated free radicals and raised the activity of glutathione peroxidase and superoxide dismutase. The second layer is indirect: under ischaemia, expression of the transcription factor Nrf2 rose, and Nrf2 switches on the cell’s response to oxidative stress (Shchulkin, 2018, PMID 30830123).

The third layer is succinate. Succinic acid is an intermediate in the Krebs cycle and a substrate of complex II of the respiratory chain, so when oxygen is short it can keep ATP production going by that route. The same review also assigns it a signalling role through the GPR91 receptor (Shchulkin, 2018). A 2018 rodent study showed that succinate regulates the rapid expression of HIF-1α in the cerebral cortex, the protein that switches cell metabolism into hypoxia mode (Lukyanova et al., 2018, PMID 29308570). In practice, the succinate salt combines a radical scavenger and an energy substrate in a single molecule.

On top of this come receptor effects, described only in models. In brain slices from young rats, emoxypine at millimolar concentrations, very high by the standards of receptor pharmacology, suppressed excitatory currents in the vestibular nucleus and the hippocampus, and an NMDA receptor antagonist abolished most of that effect (Motin et al., 2012, PMID 22442954). In rats after transient cerebral ischaemia the compound increased local blood flow, and bicuculline, a GABA receptor blocker, abolished that action (Gnezdilova et al., 2010, PMID 21254506). None of these results points to a single target receptor; emoxypine remains a compound with several parallel, poorly separated mechanisms.

Interactions were examined in cell lines. Emoxypine succinate inhibited the transporters ABCB1 (P-glycoprotein) and SLCO1B1 but was not a substrate of either; by the criteria of the FDA and the International Transporter Consortium, systemic inhibition is not clinically significant, while inhibition of ABCB1 in the gut would need to be tested in humans (Shchulkin et al., 2023, PMID 38004395).

What animal studies showed

The most frequently cited behavioural thread is anxiety. In rats with alloxan-induced diabetes, three 3-hydroxypyridine and succinic acid derivatives given for 14 days reduced anxiety-like behaviour in the elevated plus maze and shortened immobility in the Porsolt test. Emoxypine was the only one to lower anxiety not just relative to diabetic controls but also relative to healthy animals, and together with Mexidol it lowered hyperglycaemia (Volchegorskii et al., 2017, PMID 28638031). That is a rodent model of metabolic disease, not a study of anxiety in people.

A second example concerns acute alcohol intoxication. Mice given ethanol showed drooping eyelids, an impaired gait and weaker limb strength at 3 and 24 hours; in animals given emoxypine succinate 15 minutes after the alcohol, the measured parameters did not differ from controls (Shchulkin et al., 2024, PMID 38954302). Russian experimental pharmacology has also compared emoxypine with Semax in rat models of cerebral ischaemia (Iasnetsov and Voronina, 2009, PMID 19334516); the mechanism and state of the evidence for that peptide are covered in our separate article on Semax.

Clinical trials: one manufacturer’s programme

The first randomised, double-blind, placebo-controlled trial was published in 2006. It enrolled 51 patients in the acute phase of ischaemic stroke who received Mexidol for 14 days, and 27 who received placebo. On day 14 the neurological deficit on the NIH scale regressed faster in the treated group, and in patients enrolled within the first 6 hours of onset the Barthel score on day 21 was better as well (Skvortsova et al., 2006, PMID 39320346).

The later trials form a sponsor’s programme. EPICA (2017): 150 patients with hemispheric stroke, intravenous treatment for 10 days followed by oral treatment for 8 weeks; at the end, a lower mean score on the modified Rankin scale than with placebo (p = 0.04) (Stakhovskaya et al., 2017, PMID 28665371). MEMO (2021): 318 patients with chronic cerebral ischaemia at 15 centres in Russia and Uzbekistan; the primary endpoint was the change in the MoCA score, and the lower bound of the 95% confidence interval for the between-group difference was 1.51 points (Fedin et al., 2021, PMID 34932280). MIR (2025): 304 stroke patients in an international trial conducted, according to the ClinicalTrials.gov registry, in Russia, Kazakhstan and Uzbekistan, with a smaller degree of disability on the Rankin scale at the end of treatment (Shamalov et al., 2025, PMID 40898634). MEGA (2022): 333 children aged 6 to 12 with ADHD, 14 centres, 42 days of treatment, with a difference from placebo on the inattention and hyperactivity subscales of the SNAP-IV questionnaire (Zavadenko et al., 2022, PMID 35485068).

There are summaries too. A meta-analysis of ten randomised trials in patients with chronic cerebral ischaemia and cognitive impairment (482 treated, 455 in comparison groups) gave a difference of 2.06 MoCA points in favour of Mexidol, with a confidence interval from 0.98 to 3.14 (Zakharov and Vakhnina, 2024, PMID 38261288). A systematic review of stroke studies covered 11 papers, of which only 2 were randomised and 9 were unblinded cohort studies; the authors noted substantial heterogeneity and judged that the evidence needs further examination (Voznyuk et al., 2023, PMID 38148698). From outside Russia comes a systematic review of treatments for diabetic peripheral neuropathy in Diabetic Medicine, where Mexidol was listed among interventions with a significant improvement in symptoms, alongside α-lipoic acid, opioids and botulinum toxin (Çakici et al., 2016, PMID 26822889); it rested, however, on the same Russian trials.

How to read this evidence

The patient numbers are impressive, but the structure of that body of evidence is uniform. The ClinicalTrials.gov registry holds 10 trials of Mexidol, 9 of them registered by the manufacturer, Pharmasoft; all were conducted in Russia, Kazakhstan or Uzbekistan (queried on 3 November 2026). Almost all clinical publications appeared in a single journal, the Korsakov Journal of Neurology and Psychiatry, in Russian with an English abstract. A PubMed query for English-language clinical trials of emoxypine returns two records: a controlled study from 2007 in 126 people with tension-type headache, unblinded and with Mexidol added to standard therapy (Medvedeva et al., 2007, PMID 17505806), and a single-blind study in women with an exacerbation of chronic inflammation of the uterus and adnexa, in which three derivatives were added to treatment (Volchegorskii et al., 2014, PMID 24771373). Both are translations of Russian papers in English-language editions of Russian journals.

Three limitations follow. First, none of these trials was reviewed by EMA or FDA, because the manufacturer never filed there. Second, there is no independent replication outside the countries where the medicine is registered. Third, the meta-analyses pool trials of differing designs and quality, as their own authors concede. For the reader this means that clinical data on emoxypine exist, but they come from a single ecosystem that has not undergone external verification. The wider background is in the guide to nootropic substances.

Regulatory status

Russia and the CIS. Mexidol® is a prescription medicine in Russia as tablets, a solution for injection and Mexidol® Forte 250; the current marketing authorisations date from 2020 and the holder is Pharmasoft (state register GRLS, as of 23 October 2026). A 2026 analysis of the registers of the Commonwealth of Independent States lists ethylmethylhydroxypyridine succinate among medicines registered in Russia, Armenia, Belarus, Kazakhstan and Uzbekistan and included on their essential medicines lists (Alexandrova et al., 2026, PMID 41467376). In Ukraine the compound is sold under the names Mexidol, Mexicor and Armadin Long (Jędrejko et al., 2024, PMID 38403950).

European Union. No medicinal product containing emoxypine is authorised: it is absent from the Article 57 data that EMA publishes on medicines authorised in the member states (data as of 9 October 2026, file downloaded 3 November 2026). In the EU it is likewise not authorised as a food or food supplement ingredient.

United States. The Drugs@FDA database lists no product containing emoxypine (checked 3 November 2026). Since the compound is not a peptide, the 503A bulk substances procedure that applies to many research peptides does not arise here. The reagent in our catalogue is material for laboratory research and may be described only as such. The identity of a batch, including whether the succinate salt rather than the free base was supplied, is confirmed by an analytical document; how to read it is explained in our article on the certificate of analysis.

Anti-doping note

The WADA 2026 Prohibited List does not name emoxypine, and the 2027 List, which takes effect on 1 January 2027, does not add it. Class S0, reserved for substances with no approval for human use, does not cover it because of the medicine’s registration in Russia. That does not close the matter. The authors of a 2024 review in Drug Testing and Analysis, among them specialists from an anti-doping laboratory, compared the action of Mexidol with meldonium and trimetazidine, which sit in class S4.4 (metabolic modulators), noted confirmed past use of the medicine by Russian athletes, and concluded that substances of this group might warrant consideration by WADA (Jędrejko et al., 2024). For an athlete this means the status could change: class S4.4 names meldonium and trimetazidine explicitly, and emoxypine is not in it today. The same List binds athletes tested in the United States through USADA, a signatory to the World Anti-Doping Code.

A separate thread concerns analytical detection. The veterinary medicine Emidonol breaks down in the body into meldonium and emoxypine; in a pilot study in three volunteers who drank milk from treated cows, both compounds were detected in urine, which is why emoxypine has been proposed as a marker of unintended meldonium doping (Postnikov et al., 2026, PMID 41611212). How the List treats research compounds and medicines registered in only some countries is explained in our guide to the WADA Prohibited List; the decision always rests with WADA and the national agencies.

Frequently asked questions

What is emoxypine?
A synthetic 3-hydroxypyridine derivative, structurally related to vitamin B6, used in Russia as the medicine Mexidol® in the form of a salt with succinic acid. It acts as an antioxidant, and the succinate is a Krebs cycle substrate.

Are emoxypine and Mexidol the same thing?
Mexidol® is the trade name of the medicine containing emoxypine succinate. Emoxypine itself is the base without succinic acid; older Russian papers studied the hydrochloride under the name “emoxipine”. The certificate of analysis should state which form is in the batch.

Is emoxypine an approved medicine in the EU or the United States?
No. It has no marketing authorisation in any EU member state, and in the United States there is no approved medicine containing it. Registrations cover Russia and some CIS countries.

Are the Mexidol clinical trials reliable?
Randomised placebo-controlled trials exist, including ones with several hundred participants, as do meta-analyses. All were run in countries where the medicine is registered, most were sponsored by the manufacturer, and none was submitted to a Western agency for review. The data are real, but they have not been independently verified.

Why do we give no dosing information for emoxypine?
The material in our catalogue is for laboratory work, not for administration to anyone, and the figures in the Russian trials describe the medicine Mexidol® used under medical supervision in specific diseases. Transferring them to another product has no basis.

Is emoxypine prohibited in sport?
It is not on the 2026 or 2027 Prohibited List and does not fall under class S0, because of its registration in Russia. A 2024 review, however, compares it to meldonium from class S4.4 and suggests WADA may take it up. Athletes should check the current List before any decision.

Summary

Emoxypine is a 3-hydroxypyridine derivative structurally close to vitamin B6 and, combined with succinate, it pairs radical scavenging with a Krebs cycle substrate; models have also described effects on NMDA and GABA receptors. As the medicine Mexidol® it is registered in Russia and some CIS countries and has a clinical trial programme in stroke, chronic cerebral ischaemia and ADHD, run by a single manufacturer and published mainly in one Russian journal. In the EU and the United States it is neither a medicine nor a supplement ingredient. The WADA List does not name it and registration excludes class S0, but a 2024 anti-doping review places it next to meldonium.

Product documentation

Reagent page with batch documentation: MEXI (emoxypine succinate). Compounds studied in the context of the central nervous system are collected in the category research materials, area: brain. The identity and purity of each batch are confirmed by a certificate of analysis.

Bibliography

1. Gupta DS, Bagwe Parab S, Kaur G. Promising effects of emoxypine and its succinate derivative in the management of various diseases-with insights on recent patent applications. Curr Res Pharmacol Drug Discov. 2022;3:100121. doi:10.1016/j.crphar.2022.100121. PMID: 35992374
2. Voronina TA. [Mexidol: the spectrum of pharmacological effects]. Zh Nevrol Psikhiatr Im S S Korsakova. 2012;112(12):86-90. PMID: 23461005 (in Russian)
3. Shchulkin AV. [A modern concept of antihypoxic and antioxidant effects of mexidol]. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(12 Vyp 2):87-93. doi:10.17116/jnevro201811812287. PMID: 30830123 (in Russian, English abstract)
4. Lukyanova LD, Kirova YI, Germanova EL. The Role of Succinate in Regulation of Immediate HIF-1α Expression in Hypoxia. Bull Exp Biol Med. 2018;164(3):298-303. doi:10.1007/s10517-018-3976-2. PMID: 29308570
5. Motin VG, Iasnetsov VV, Zabozlaev AA, et al. [Electrophysiological study of the mechanism of mexidol action]. Eksp Klin Farmakol. 2012;75(1):3-7. PMID: 22442954 (in Russian)
6. Gnezdilova AV, Gan’shina TS, Mirzoian RS. [GABAergic mechanism of cerebrovascular effect of mexidol]. Eksp Klin Farmakol. 2010;73(10):11-13. PMID: 21254506 (in Russian)
7. Shchulkin AV, Erokhina PD, Goncharenko AV, et al. Ethylmethylhydroxypyridine Succinate Is an Inhibitor but Not a Substrate of ABCB1 and SLCO1B1. Pharmaceuticals (Basel). 2023;16(11):1529. doi:10.3390/ph16111529. PMID: 38004395
8. Volchegorskii IA, Miroshnichenko IY, Rassokhina LM, et al. [Anxiolytic and antidepressant effects of emoxipine, reamberin and mexidol in experimental diabetes mellitus]. Zh Nevrol Psikhiatr Im S S Korsakova. 2017;117(5):52-57. doi:10.17116/jnevro20171175152-57. PMID: 28638031 (in Russian)
9. Shchulkin AV, Abalenikhina YV, Mylnikov PY. The Study of the Effectiveness of Ethylmethylhydroxypyridine Succinate in Acute Alcohol Intoxication. Bull Exp Biol Med. 2024;177(1):51-56. doi:10.1007/s10517-024-06130-y. PMID: 38954302
10. Iasnetsov VV, Voronina TA. [Effect of semax and mexidol on brain ischemia models in rats]. Eksp Klin Farmakol. 2009;72(1):68-70. PMID: 19334516 (in Russian)
11. Skvortsova VI, Stakhovskaya LV, Nartsyssov YR, et al. [The randomized double-blind placebo-controlled study of efficacy and safety of mexidol in the complex therapy of ischemic stroke in the acute period]. Zh Nevrol Psikhiatr Im S S Korsakova. 2006;106(12 Vyp 2):47-54. PMID: 39320346 (in Russian)
12. Stakhovskaya LV, Shamalov NA, Khasanova DR, et al. [Results of a randomized double blind multicenter placebo-controlled, in parallel groups trial of the efficacy and safety of prolonged sequential therapy with mexidol in the acute and early recovery stages of hemispheric ischemic stroke (EPICA)]. Zh Nevrol Psikhiatr Im S S Korsakova. 2017;117(3 Vyp 2):55-65. doi:10.17116/jnevro20171173255-65. PMID: 28665371 (in Russian)
13. Fedin AI, Zakharov VV, Tanashyan MM, et al. [Results of an international multicenter, randomized, double-blind, placebo-controlled study assessing the efficacy and safety of sequential therapy with Mexidol and Mexidol FORTE 250 in patients with chronic brain ischemia (MEMO)]. Zh Nevrol Psikhiatr Im S S Korsakova. 2021;121(11):7-16. doi:10.17116/jnevro20211211117. PMID: 34932280 (in Russian)
14. Shamalov NA, Fedin AI, Rakhimbaeva GS, et al. [Results of the international multicenter randomized, double-blind, placebo-controlled clinical trial for the evaluation of the efficacy and safety of the sequential therapy with ethylmethylhydroxypyridine succinate in patients in the acute and early recovery periods of ischemic stroke (MIR)]. Zh Nevrol Psikhiatr Im S S Korsakova. 2025;125(8 Vyp 2):40-53. doi:10.17116/jnevro202512508240. PMID: 40898634 (in Russian)
15. Zavadenko NN, Suvorinova NY, Batysheva TT, et al. [Results of a multicentre double-blind randomised placebo-controlled clinical trial evaluating the efficacy and safety of Mexidol in the treatment of Attention Deficit Hyperactivity Disorder in Children (MEGA)]. Zh Nevrol Psikhiatr Im S S Korsakova. 2022;122(4):75-86. doi:10.17116/jnevro202212204175. PMID: 35485068 (in Russian)
16. Zakharov VV, Vakhnina NV. [The use of Mexidol in patients with mild (moderate) cognitive impairment: results of a meta-analysis]. Zh Nevrol Psikhiatr Im S S Korsakova. 2024;124(1):82-88. doi:10.17116/jnevro202412401182. PMID: 38261288 (in Russian)
17. Voznyuk IA, Kolomentsev SV, Morozova EM. [The impact of therapy with Mexidol on neurological deficit and functional outcome in patients with ischemic stroke: a systematic review and meta-analysis]. Zh Nevrol Psikhiatr Im S S Korsakova. 2023;123(12 Vyp 2):49-60. doi:10.17116/jnevro202312312249. PMID: 38148698 (in Russian)
18. Çakici N, Fakkel TM, van Neck JW, et al. Systematic review of treatments for diabetic peripheral neuropathy. Diabet Med. 2016;33(11):1466-1476. doi:10.1111/dme.13083. PMID: 26822889
19. Medvedeva LA, Gnezdilov AV, Zagorul’ko OI, et al. Efficacy of neuroprotectors in patients with tension headaches. Neurosci Behav Physiol. 2007;37(5):523-526. doi:10.1007/s11055-007-0046-z. PMID: 17505806
20. Volchegorskii IA, Pravdin EV, Uzlova TV. Effects of 3-hydroxypyridine derivatives and succinic acid on endometrial leukocyte infiltration, cytokinemia and related affective symptoms during exacerbation of the chronic inflammation of the uterus and adnexa. Bull Exp Biol Med. 2014;156(3):347-352. doi:10.1007/s10517-014-2346-y. PMID: 24771373
21. Jędrejko K, Catlin O, Stewart T, Muszyńska B. Mexidol, Cytoflavin, and succinic acid derivatives as antihypoxic, anti-ischemic metabolic modulators, and ergogenic aids in athletes and consideration of their potential as performance enhancing drugs. Drug Test Anal. 2024;16(12):1436-1467. doi:10.1002/dta.3655. PMID: 38403950
22. Postnikov PV, Efimova YA, Rodin IA. Emoxypine as a Potential Marker for Identifying Possible Cases of Unintended Meldonium Doping in Sports. Drug Test Anal. 2026;18(3):414-418. doi:10.1002/dta.70031. PMID: 41611212
23. Alexandrova EG, Abakumova TR, Ziganshina LE. Use of nootropics in Alzheimer’s disease: An analysis of regulatory positions and drug policies in the countries of the Commonwealth of Independent States. Int J Risk Saf Med. 2026;37(2):257-264. doi:10.1177/09246479251410817. PMID: 41467376
24. State Register of Medicines of the Russian Federation (GRLS). Entries for Мексидол®: tablets (ЛП-№(000086)-(РГ-RU), 30 October 2020), solution (ЛП-№(000107)-(РГ-RU), 29 December 2020), Мексидол® ФОРТЕ 250 (ЛП-№(000066)-(РГ-RU), 3 June 2020). grls.rosminzdrav.ru (register export of 23 October 2026)
25. National Center for Biotechnology Information. PubChem Compound Summary, CID 114681 (emoxypine) and CID 122298 (ethylmethylhydroxypyridine succinate). pubchem.ncbi.nlm.nih.gov (accessed 3 November 2026)
26. ClinicalTrials.gov. Query “mexidol OR emoxypine OR ethylmethylhydroxypyridine”: 10 studies, 9 of them sponsored by Pharmasoft. clinicaltrials.gov (accessed 3 November 2026)
27. European Medicines Agency. Article 57 product data (data as of 9 October 2026): no entry for emoxypine. ema.europa.eu (accessed 3 November 2026)
28. U.S. Food and Drug Administration. Drugs@FDA: no product containing emoxypine. accessdata.fda.gov (accessed 3 November 2026)
29. World Anti-Doping Agency. The 2026 Prohibited List. wada-ama.org (accessed 3 November 2026)
30. U.S. Anti-Doping Agency. Athlete Advisory: What’s New on the 2027 WADA Prohibited List? (6 October 2026). usada.org (accessed 3 November 2026)