I'm also a 50-something and I can totally relate to what you are saying in regards to the aches, pains and concentration skills. I was another one of those whose joints creaked in the morning and ached at night, and within two weeks, I felt decade younger.
More flexibility, less inflammation and joint pain. I also found myself able to concentrate at a higher level for longer periods of time.
I'm four months out from when I started W30, and my habits, lifestyle and heath have all changed dramatically for the positive. The type of fuel we put in the one engine we have DOES matter. It j