Study finds wildly varying concentration of bioactives in Mucuna pruriens supplements

The new study was the work of a team led by prominent industry critic Dr Pieter Cohen, MD, who is associated with Harvard Medical School.  Dr Ikhlas Khan, PhD, was listed as a coauthor as well as other experts from the University of Mississippi. It was published in the journal JAMA Neurology.​

Botanical with noted neurological effects

Mucuna pruriens​, known as velvet bean among many other common names, is a legume native to tropical Africa as well as the Asian Subcontinent.  According to a 2012 study in the Journal of Traditional and Complimentary Medicine​​, it has been used management of male infertility, nervous disorders, and also as an aphrodisiac. Within the Ayurvedic system it has also been used for its neurocognitive effects, which specifically relates to the plant’s L-dopa, or ‘levodopa’ content.

The plant has been studied for its effects on Parkinson’s Disease symptoms in an RCT conducted in 2017​​.  That study found that a high dose M. pruriens​ extract performed similarly well to levodopa presented as a standalone botanical drug, with improved tolerability.

The authors of the present study expressed a concern, then, whether consumers seeking to self treat incipient Parkinson’s or other neurological conditions would be reaching for an M. pruriens​ supplement which might complicate their treatment if the supplements contain unknown amounts of levodopa.

Wildly varying concentrations

The authors identified 20 of the most recently added brands to the NIH Dietary Supplement Label Database for analysis. To qualify for inclusion in the study the products had to say both ‘dietary supplement’ and ‘Mucuna pruriens​’ on the label. The researchers excluded four entries for various reasons and ended up with 16 products which were purchased and analyzed.

In addition, for benchmark purposes two authenticated examples of M. pruriens​ seeds were obtained from the National Center for Natural Products Research at the University of Mississippi and extracted to see what the ‘natural’ level of levodopa in the parent plant is.

The supplement analysis revealed that the supplements contained dosages ranging from 2 mg to 241 mg of levodopa per recommended serving size.  The benchmark seed extract samples had 2.5% to 3.9% levodopa.  For those products that listed an amount of M. pruriens​ seed extract on the label (only about half of them did), the supplements contained from 228% to 2,186% of the expected amount of levodopa in them.

“Given these findings, clinicians may identify unsuspected levodopa consumption by asking patients about the use of supplements and advising that consumption of M pruriens supplements may unpredictably complicate the management of Parkinson and other diseases,”​ the authors concluded.

Source:​ JAMA Neurology​​.​
Published online August 8, 2022. doi:10.1001/jamaneurol.2022.2184
Levodopa Content of ​Mucuna pruriens Supplements in the NIH Dietary Supplement Label Database​
Authors: Cohen PA, Avula B, Katragunta K, Khan, I.