NOTHING like a cancer worry or anything like that. My Dr seems to think a drop in B-12 might be the blame. I haven't been check for that in close to 8-9 years. The past 3-4 years, I find myself feeling drained at times. I can sleep well the night before but still feel sluggish. This time of year (Heat / HUMIDITY) really doesn't help. I had been taking Men's One A Day gummies but my Dr said those are more sugar than anything and a bit of a waste.