http://www.lef.org/protocols/prtcl-088b.shtml In this study, cited in the October 2002 issue of Archives of Neurolgy, 80 Parkinson's patients consumed varying potencies of coenzyme Q10 or placebo for up to 16 months (Schults et al. 2002). When the study ended, the patients consuming the highest potency of CoQ10 showed a 44% reduction in the decline of motor skills, movement and mental function compared to the placebo group. Those receiving high-dose CoQ10 also demonstrated an improved ability to perform daily living tasks.
The dose required to induce this dramatic affect was 1200 mg a day, a far higher amount than had ever been administered to humans in the past. CoQ10 did not improve symptoms the way current Parkinson's drugs do. Instead, CoQ10 slowed the progression of the disease, something that Parkinson's drugs don't do.
Independent analysts stated that these results were "tremendously encouraging," but cautioned that more studies should be done to confirm these effects. While Life Extension encourages more studies, it would appear that those with Parkinson's disease should consider supplementing with 1200 mg of CoQ10 a day.
In a 2003 report published in Neuroscience Letters (Muller et al.), 360 mg per day of CoQ10 were administered to Parkinson’s patients for 4 weeks. The researchers noted mild symptomatic improvement compared to placebo. More importantly, an established clinical test to measure Parkinson’s symptom function showed significantly better improvement of performance in the CoQ10-supplemented patients compared to placebo.