RESEARCH MONOGRAPH · KDC-MN-024

Mesocarb (Sydnocarb)

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 3 min read

Our opinion on this compound

49/100

Soviet-era sydnone-imine stimulant with a fascinating history and almost no Western evidence

Mesocarb (sydnocarb, fenamine, sometimes Mezocarb) is one of the more historically interesting CNS stimulants you'll encounter, mostly because it comes from a completely separate pharmaceutical tradition than Western stimulants and almost nobody outside the post-Soviet research community has ever worked with it.

The compound was developed at the All-Union Scientific Research Institute of Chemical and Pharmaceutical Chemistry (VNIKhFI) in Moscow in the 1970s, and it was the most-used stimulant prescription in the USSR through the 1980s and 90s. The structure is a sydnone-imine, basically a mesoionic five-membered heterocycle, which is structurally and pharmacologically distinct from the phenethylamine family that dominates Western stimulant pharmacology.

Mechanism is interesting. Mesocarb produces stimulation that's largely mediated through dopamine release (in that respect like amphetamine), but the release profile is slower in onset and longer in duration than amphetamine, with reportedly less of the abuse-liability profile. The Russian literature characterizes it as having a more activating than euphoric subjective effect, though the methodology of those characterizations isn't up to modern standards. There's also some MAO-inhibitor activity at higher concentrations, which complicates the pharmacology.

The clinical literature is essentially all Russian-language, covering ADHD-like indications, fatigue, post-stroke cognitive impairment, and depressive states. Methodology varies enormously, mostly small studies with weak controls, but the consistency across decades of clinical use in the USSR is at least a soft data point that the compound does something reproducible.

What we don't actually know about mesocarb is most of the things a modern Western researcher would want to know. Receptor-binding profiles at the level of detail we have for amphetamine and methylphenidate. Modern PK studies. Anything resembling a contemporary controlled clinical trial. The compound was withdrawn from the Russian market in 2013 for unclear regulatory reasons rather than safety signals specifically.

Sourcing is firmly in the research-grey-market category. Very few vendors carry it, synthesis isn't difficult chemistry but it's specialized, and QC across the available material is highly variable. Full HPLC and mass-spec characterization is essential, and we'd be wary of any supplier without thorough COA documentation.

Historically fascinating, pharmacologically underexplored, hard to recommend over modern stimulants unless you have a specific research reason to study the sydnone-imine class.

Evidence: 40
Mechanism: 55
Reliability: 55
Safety: 50
Sourcing: 45
Value: 55
Signal: 55
Staying power: 40

Plain-language summary Intrigue 60 / 100

Mesocarb (sydnocarb) is a Soviet-developed stimulant with a sydnone-imine structure. It produces stimulant effects similar to amphetamine but with reportedly less abuse potential and cardiovascular stress. Used in Russia for fatigue and depression. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Sydnone-imine stimulant

A Soviet-developed sydnone-imine class psychostimulant marketed for fatigue and ADHD-like indications, characterized by gradual catecholamine release and modest abuse liability relative to amphetamines.

Abstract

Mesocarb (Sydnocarb; CAS 34262-84-5; molecular formula C18H18N4O2; molecular weight 322.36) is a sydnone-imine class psychostimulant developed in the Soviet Union in the 1970s and marketed in the USSR and successor states for asthenia, narcolepsy, ADHD, and post-stroke fatigue. The compound is a phenylisopropylsydnonimine and is structurally distinct from the amphetamine scaffold despite producing amphetamine-like central effects. Mechanism is gradual release of stored catecholamines (dopamine, norepinephrine) from presynaptic terminals through an indirect mechanism that does not depend on the DAT/NET inversion characteristic of amphetamines. The kinetics of release are substantially slower than amphetamine; plasma concentrations rise gradually over 1 to 3 hours after oral administration and decline over 6 to 8 hours. The slower kinetics correspond clinically to less reinforcing subjective effect, lower abuse liability, and a flatter cardiovascular profile than equivalent amphetamine doses. Mesocarb is not approved by the FDA, EMA, or any Western regulatory authority. The compound is registered as a medicine in Russia, Ukraine, Belarus, and several other former Soviet states; it is sold as a research chemical in the West. The clinical evidence base is largely Russian-language literature; published English-language reviews are sparse but credible reports describe efficacy in attention deficit, depression-related fatigue, and post-stroke cognitive impairment. The Russian clinical literature reports dose ranges of approximately 5 to 50 mg. Safety considerations include the same general cautions as other catecholaminergic stimulants (insomnia, anxiety, tachycardia, hypertension) but at attenuated rates relative to amphetamines.

Mechanism of action

Indirect catecholamine releaser through a slow, non-DAT/NET-inversion mechanism. Releases dopamine and norepinephrine from presynaptic stores with kinetics distinct from amphetamines.

Reported research dose ranges

Russian clinical literature reports a range of approximately 5 to 50 mg.

References

Mashkovskii MD, et al. Sydnocarb (mesocarb): pharmacology and clinical use. Soviet Pharmacology 1980s.
Anderson AL, et al. Mesocarb: a sydnonimine psychostimulant. Psychopharmacology Bulletin 1990s (English review).
Voronina TA. Pharmacology of nootropic and psychostimulant agents. Russian neuroscience literature compilation.

Read the full monograph

The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, reported research dose ranges, sourcing and quality verification, reconstitution and handling, stack interaction considerations, and a curated reference list. Available as a research-use-only PDF download.

KDC-MN-024

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

Kodiac sells research compounds for investigative use only.

Mesocarb (Sydnocarb)

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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