Levodopa Content of Mucuna pruriens Supplements in the NIH Dietary Supplement Label Database

Abstract

This case series assesses the levels of levodopa in Mucuna pruriens supplements available in the US that are included in the National Institutes of Health Dietary Supplement Label Database.

Botanical supplements may contain pharmaceutically active drugs that affect the presentation, natural history, and management of disease. One example is Mucuna pruriens, a bean containing levodopa, which has been investigated as a potential treatment for Parkinson disease.¹ The prevalence of M pruriens supplement use in the US is unknown, but a recent survey of 205 patients with Parkinson disease found that 7% of supplement users used M pruriens supplements to treat the disease.²

The Office of Dietary Supplements at the National Institutes of Health (NIH) maintains an online database of dietary supplement labels.³ This case series study was designed to measure the levodopa content of M pruriens supplements in the NIH’s database and compare the quantity of levodopa in the supplements with the quantity of levodopa in extracts of authenticated M pruriens seeds.

Methods

In November 2021, supplements with “Mucuna pruriens” on the label in the NIH Dietary Supplement Label Database were identified. The 20 brands most recently added to the database in 2021 were purchased online. Products were excluded from this case series if the actual label did not contain both “dietary supplement” and “Mucuna pruriens.” Two authenticated samples of M pruriens seeds were obtained from the National Center for Natural Products Research repository at the University of Mississippi.

Ground seeds and powder from dietary supplement products were reconstituted in water. All samples were analyzed for the presence and quantity of levodopa using ultra high-performance liquid chromatography. For products that listed a specific amount of M pruriens seed extract per serving on the label, estimated quantity of levodopa was calculated by multiplying the declared quantity of M pruriens seed extract by the highest percentage of levodopa found in the extracts of authentic M pruriens seeds. Products were also screened for the presence of carbidopa and benserazide. eMethods 1 to 6 in the Supplement include additional details.

Results

Of the 20 supplement products identified in the database, 1 was unavailable for purchase, 1 was a duplicate entry, and 2 did not contain both “Mucuna pruriens” and “dietary supplement” on the actual label; therefore, 16 products were analyzed. One product did not contain detectable levels of levodopa. In the remaining 15 products, the quantity of levodopa ranged from 2 mg to 241 mg per recommended serving size (Table). Extracts from authenticated M pruriens seeds were found to contain 2.5% to 3.9% levodopa. In supplement products that listed a specific quantity of M pruriens seed extract on the label, the actual quantity of levodopa was 228% to 2186% greater than the estimated quantity. Carbidopa and benserazide were not detected.

Table. Information Regarding Mucuna pruriens Seed Extract on Labels of Dietary Supplements Compared With Quantity Detected in Analyzed Samples of Supplements.

Claim on label	Description of M pruriens according to label	Amount per serving size of M pruriens seed extract according to label, mg	Measured levodopa per serving size, mean (SD), mg/estimated levodopa per serving size, mg [%]a
Strength, power, performance	M pruriens seed extract; std to 98% naturally occurring levodopa	150	129.1 (0.2)/5.9 [2186]
Brain support	Mucuna seed extract (M pruriens); std to contain 60% levodopa (3,4 dihydroxy-L-phenylalanine)	425	241 (0.3)/16.6 [1452]
Preworkout	M pruriens; std 98% levodopa	NA	78.9 (0.5)/NP
Brain support	Mucuna extract (Mucuna spp seed); minimum 15% naturally occurring levodopa or levodopa	800	154.2 (0.3)/31.2 [494]
No claim	Organic M pruriens seed extract 10:1; 15% naturally occurring levodopa	250	53.1 (0.3)/9.8 [544]
Positive mood, mental clarity and focus, performance, hormone health	Natural M pruriens seed extract	1000	94.4 (1.0)/39 [242]
Supports dopamine production and motivation	M pruriens seed extract	250	93.8 (0)/9.8 [957]
Fat metabolism, appetite control, focus and stimulation	M pruriens seed extract	NA	31.5 (1.1)/NP
Dopamine and serotonin boosters	Mucuna (M pruriens) bean	NA	56.2 (0.1)/NP
Cognitive support	M pruriens seed extract	600	53.4 (0.8)/23.4 [228]
Dopamine bean	Mucuna (M pruriens) bean	NA	17.3 (0.5)/NP
Natural source of energy	M pruriens seed extract; std to contain minimum 50% levodopa	95	12.4 (0.5)/3.7 [335]
Rest and rejuvenation support	M pruriens; 15% extract (seed)	50	7.4 (1.2)/2.0 [370]
Fat burner	M pruriens; std to 98% levodopa	NA	2.0 (0.2)/NP
Deep calm	M pruriens (seed)	NA	3.4 (0.3)/NP
Adaptogen	Organic Mucuna (M pruriens) seed extract 20:1	NA	Not detected/NPb

Abbreviations: NA, not available; NP, not possible (estimate not possible given lack of declared quantity of M pruriens seed extract on label); spp, species; std, standardized.

^a Estimated quantity of levodopa calculated by multiplying the declared quantity of the M pruriens seed extract listed on the label (in mg) by the highest percentage of levodopa found in the extracts of authenticated M pruriens seeds (3.9%).

^b Detection limit of 50 ng/mL for levodopa.

Discussion

Levodopa doses from 2 mg to 241 mg in M pruriens supplements were unpredictable based on the declared quantity of M pruriens seed extract on the label. One previous investigation of 6 M pruriens supplements sold in the US also found a wide range of levodopa (from 4 mg to 354 mg per serving).⁴ It is not possible to directly compare the pharmacologic effects of levodopa in M pruriens supplements with prescription levodopa, typically formulated in 50-, 100-, 200-, and 250-mg doses, in part because prescription levodopa includes a peripheral decarboxylase inhibitor not present in M pruriens supplements.

This study has several limitations. Only 2 authenticated samples of M pruriens seed extracts were analyzed, and it is possible that different variants of M pruriens or different extraction methods might affect the quantity of levodopa.⁵ In addition, only 1 sample of each brand of supplement was analyzed, and it remains unknown if the dose of levodopa varies from batch to batch over time. 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.

Supplement.

eMethods 1. Chemicals, Reagents, and Dietary Supplements

eMethods 2. Preparation of Authenticated Mucuna pruriens Seeds and Dietary Supplement Samples

eMethods 3. Instrumental Conditions

eMethods 4. Validation of the Identification Methodology

eMethods 5. Validation of the Quantification Methodology

eMethods 6. Screening for Carbidopa and Benserazide in Authenticated Seed Extracts and Dietary Supplement Samples

eReferences