Have you had your DHEA level tested? Most hospitals and some clinics can do this. It starts dropping rapidly after 50 and can have a significant affect on your libido. There are supplements for it, but there’s no evidence they work. Most men over 50 “peak” in the mornings and drops as the day progresses, regardless of lifestyle, fitness level, etc. If you want to get it up and keep it up later in the day, the blue pills are your answer. After all, that is why they were invented. That’s life!