RESEARCH MONOGRAPH · KDC-MN-227

Tranylcypromine

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

Our opinion on this compound

74/100

Amphetamine-shaped MAOI with a kick the others dont have, and a reputation that survived the SSRI era for good reasons

Tranylcypromine is the cyclopropylamine MAOI thats structurally derived from amphetamine, and that lineage isnt incidental. Tranylcypromine inhibits MAO-A and MAO-B irreversibly through the cyclopropylamine warhead, but it also has direct catecholamine-releasing activity at norepinephrine and dopamine terminals because the amphetamine pharmacology is still in the molecule. So you get the standard non-selective MAOI effects plus a stimulant kick on top.

That stimulant component is part of why tranylcypromine has the clinical reputation it does. In treatment-resistant depression and atypical depression, head-to-head data versus phenelzine and versus modern agents has consistently shown that tranylcypromine moves the needle in patients who haven't responded to anything else. The Fava and Nierenberg work is worth reading, and the European data from the Bauer group has been consistent on this for years.

What we find interesting for research is the dual mechanism. Single molecule that gives you irreversible MAO inhibition plus catecholamine releasing activity, which is essentially a chemical reproduction of what amphetamine-plus-MAOI combinations achieve clinically without the polypharmacy. In animal models thats useful for studying what happens at the noradrenergic synapse when you simultaneously elevate intraneuronal monoamines and force release.

The compound also has some inhibitory activity at LSD1 (lysine-specific demethylase 1), which has been a topic in epigenetics research independent of the antidepressant context. That's a real pharmacology, not a hype claim, and it's part of why tranylcypromine has gotten attention in oncology preclinical work.

What we dont like is mostly the same things that apply to all irreversible non-selective MAOIs. Tyramine pressor response is real, drug-drug interactions are genuinely dangerous, the safety margin is narrow.

Sourcing is fine. Sulfate salt is standard, reference material is clean, HPLC validation is well established. Costs are moderate.

For research this is one of the more pharmacologically rich MAOIs and the LSD1 activity gives it a second life in epigenetics tool chemistry. Worth keeping around even if you arent doing classical antidepressant work.

Evidence: 84
Mechanism: 84
Reliability: 78
Safety: 50
Sourcing: 80
Value: 72
Signal: 72
Staying power: 68

Plain-language summary Intrigue 65 / 100

Tranylcypromine (Parnate) is a first-generation MAOI from 1961 with a chemical backbone closely related to amphetamine. That structural quirk gives it a small but real direct stimulant component on top of the MAO inhibition, producing faster onset (1 to 2 weeks rather than the 4 to 6 weeks typical of MAOIs) and a more activating subjective profile than phenelzine. It carries the same dietary tyramine restrictions and drug interaction risks as the rest of its class. Like phenelzine it earns its place in the modern psychiatric armamentarium specifically for treatment-resistant depression cases where everything else has failed. The recent Tranylcypromine in Treatment-Resistant Depression literature has revived interest in disciplined modern use of these older drugs. 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.

Irreversible non-selective MAO inhibitor (amphetamine-related)

A non-hydrazine cyclopropylamine MAOI structurally related to amphetamine; rapid-onset compared to phenelzine.

Abstract

Tranylcypromine ((1S,2R)-2-phenylcyclopropan-1-amine; CAS 155-09-9; molecular formula C9H11N; molecular weight 133.19) is a non-hydrazine cyclopropylamine MAOI approved by the FDA in 1961 under the trade name Parnate. The cyclopropylamine scaffold is structurally related to amphetamine, producing weak monoamine release in addition to MAO inhibition; the result is faster antidepressant onset (1 to 2 weeks) than phenelzine (3 to 6 weeks) and a mildly activating subjective profile. Inhibition of both MAO-A and MAO-B is irreversible, with similar tyramine cheese-effect risk. Plasma half-life is 1.5 to 3.2 hours, but enzyme inhibition persists for 5 to 10 days. The (-)-trans isomer is the predominant active form; clinical preparations are racemic. Hepatic metabolism is minor; the compound is largely excreted unchanged. Approved for major depressive disorder; used in atypical and treatment-resistant depression. Used as a non-hydrazine MAOI reference compound and as a positive control in dopaminergic and norepinephrine release studies.

Mechanism of action

Irreversible non-selective MAO inhibition with weak monoamine release from amphetamine-like scaffold. Activating subjective profile.

Reported research dose ranges

Reported research dose ranges in the literature.

References

Frieling H, Bleich S. Tranylcypromine: new perspectives on an old drug. Eur Arch Psychiatry Clin Neurosci 2006.
Heinze G, et al. Tranylcypromine vs SSRIs in treatment-resistant depression. Pharmacopsychiatry 2018.
Riederer P, et al. The pharmacology of MAO inhibitors. Neurology 2004.

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KDC-MN-227

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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Tranylcypromine

Abstract

Mechanism of action

Reported research dose ranges

References

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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