COQ10 is more for the brain than leg muscles and cramps. COQ10 diminshes in our bodies from early 20's onwards. There are also varying strengths of it. To get most benefit you need to check the qty of mg that you take.
I have been taking the strongest strength for about 4 years, and it has not altered my needs for insulin or my BG's. To be quite honest, I don't actually know that it has helped my brain....other than I dread finding out what my memory and brain function would be like without taking them, so I just keep taking them.
I was on statins for 10 years and when I learned that they recommended COQ10 to be taken with them I started. I came off statins on Christmas day last year. Have had 3 cholesterol tests since then and my levels are all come in under 4.6, with good ldl and hdl levels, this monday just gone my Consultant said that I shouldn't have been on them, as it is obvious I didn't and haven't got raised cholesterol. I came off the statins because of feeling unwell on them, but statins weren't the cause of my feeling ill, it was being misdiagnosed twice with different illnesses in the past decade.....