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1928-1931 – Clinical Trials with Harmine Conducted on Parkinson’s Disease

harmine parkinsons disease

One of the most intriguing and important molecules in the ayahuasca vine Banisteriopsis caapi is undoubtedly harmine. Back in the 1840s, scientists discovered harmine in the Eurasian plant Syrian Rue. Then in the early twentieth century, they began to test its potential medicinal properties on Parkinson’s Disease. Having observed a general muscular excitation induced by harmine in preliminary studies, the German pharmacologist Louis Lewin decided to investigate the effects of harmine on human muscular rigidity.

At the Neukölln Hospital, he administered injections of harmala alkaloids, then called “banisterine”, at a dose of 0.025-0.075 grams to several patients, and it became clear that the vine had the ability to greatly improve muscle rigidity.

Encouraged by these early results, Lewin turned to Prof. Wilmanns at the Heidelberg Psychiatric Clinic, proposing to continue experiments with banisterine on patients with neuromuscular pathologies. After a first unfortunate experiment, due to an error in calculating the dose, a muscular excitation was observed by the vine on all the subjects tested.

This led Lewin to request experiments at the clinic of Kurt Beringer, a German pharmacologist who had developed a long series of clinical trials with mescaline, to test banisterine on post-encephalitic patients, and at the same time learned the substance was dangerous for cardiac patients, due to its “bradicardizing action” (1927).

harmine parkinsons
Improvement of the writing observed in a Parkinson patient before (top) and after (bottom) the subcutaneous injection of banisterine (harmine) (from Beringer, 1928b, t. 3, p. 26)

Beringer accepted Lewin’s advice and experimented with banisterine on 15 patients suffering from muscle stiffness and recovering from lethargic encephalitis. At the dose of 20-40 mg subcutaneous banisterine proved to be effective in improving motor stiffness and bradykinesia; walking was facilitated, and patients reported “feeling lightened”. The effects vanished within 1-2 hours. In particular, a marked improvement was observed in writing after the administration of banisterine from the ayahuasca vine (see figure).

Ernst Rustige also experimented 3-50 mg of subcutaneous harmine on 18 post-encephalitic Parkinsonian patients. The main result was an improvement in voluntary movements in 13 patients, and the reduction in stiffness lasted on average six hours. These patients felt faster and freer, and had also acquired greater mental clarity, according to the work of Rustige in 1929.

In 1932, Paul Schuster confirmed the effectiveness of harmine in some forms of Parkinsonism, and for prolonged treatments he recommended the combination of harmine with scopolamine or with stramonium.

The enthusiasm for the harmal alkaloids, especially harmine, in the treatment of Parkinsonism vanished after the mid-1930s. They were again taken into consideration when towards the end of the 1950s their remarkable MAO-inhibitory properties were highlighted.

While harmal alkaloids play a central role in the shamanic ayahuasca brew from the Amazon, they were only properly discovered to exist in the ayahuasca vine in 1957.

To read more about this intriguing history of ayahuasca and Parkinson’s Disease research, see this article by Xavier Francuski.


Beringer Kurt, (1928a), Die Beeinflussung des extrapyramidal-motorischen Systems durch Banisterin, Deutsche Medizinische Wochen., 22: 908-9.

Beringer Kurt, (1928b), Über ein neues, auf das extrapyramidal-motorische System wirkendes Alkaloid (Banisterin), Nervenarzt, 5: 20-30.

Lewin Louis, (1928), Untersuchungen über Banisteria Caapi Spr., Archiv für Experimental Pathologie und Pharmacologie, 129: 133-49.

Rustige Ernst, (1929), Versuche mit Harmin bei Metenzephalitikern, Deutsche Medizinische Wochen, 15: 613-614.

Schuster Paul, (1931), Hat sich das Harmin bei der Behandlung des Parkinsonismus bewährt?, Deutsche Medizinische Wochen., :1537-9.

Udenfried Sidney et al, (1958), Studies with reversible inhibitors of monoamine oxidase: harmaline and related compounds, Biochem.Pharm., 1: 160-5.

Ayahuasca Timeline – Previous and Next (Sample)

1913 – The First Syncretic Ayahuasca Religious Group, “Círculo de Regeneração e Fé” is Formed in the Brazilian Amazon
1921 – French Anthropologist P. Reinburg Reports on His Personal Experimentation with Ayahuasca
1928 – The Banisterine Experiments of Pharmacologist Louis Lewin
1928-1931 – Clinical Trials with Harmine Conducted on Parkinson’s Disease
1930 – The Church Later Known as Santo Daime is Founded by Mestre Irineu
1931-1970 – The DMT Molecule Is Synthesized and Its Psychoactive Effects on Humans are Documented

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