June 2015

Between 500,000 to 1 million Americans have Parkinson disease (PD), and an additional 50,000 to 60,000 are diagnosed with PD annually. In 2010, medical expenses for PD were estimated at $14 billion, with an additional $6 billion in indirect costs such as reduced employment. Although the number of PD treatments has increased, adverse effects commonly occur. As a result, many patients try complementary medicine such as tai chi as well as supplements. Recently, two supplements were evaluated for their ability to slow PD progression.

Coenzyme Q10


A 2014 U.S. and Canadian multicenter Phase III study evaluated the potential disease-modifying effects of coenzyme Q10 (CoQ10) on the basis of an earlier study that suggested a benefit. Among the eligibility criteria, participants were at least 30 years of age; had a resting tremor, bradykinesia, and rigidity; and were not expected to need dopaminergic therapy for at least the next 3 months.

After screening, 600 participants were randomized, with 203 assigned to placebo, 201 to CoQ10 1,200 mg daily, and 196 to CoQ10 2,400 mg daily. All participants also took 1,200 IU of vitamin E daily. Participants had a mean age of 62 years and a 2-year duration of PD. 


The primary endpoint was a 3-point change in the total United Parkinson’s Disease Rating scale (UPDRS), assessing both motor and cognitive changes as well as activities of daily living, from baseline until 16 months or the need for dopaminergic therapy. Participants were evaluated every 4 months for PD disability, and at baseline, the mean UPDRS scores were 22.7 for the groups.

The number of participants reaching the primary endpoint was similar, with 94 in the placebo group, 87 in the CoQ10 1,200-mg group, and 86 in the CoQ10 2,400-mg group. Withdrawals were similar among groups. Mean UPDRS scores were similar at 35.4, 35.2, and 36.5 for placebo, CoQ10 1,200 mg, and CoQ10 2400 mg, respectively. Adverse effects were similar.