Never in all my years have I found a medicine or supplement whose effect I can see within a day.... until now. I decided to give NAD a trial after reading this thread. http://phoenixrising.me/forums/inde...fs-nadph-measurement-at-riordan-clinic.15641/ I had tried NADH in the past with no discernible effect, so I didn't have any serious expectations for NAD, but thought I'd give it a shot since it isn't very expensive. The very first day I felt more energetic, which was surprising, but what surprised me even more what how much it affected my HR. From the first day, my first morning HR is lower. Even better, my "active" HR is significantly lower -- by 10-15 bpm. I can also do more without going over my AT. Previously I could go over my AT climbing a flight of stairs or walking 50 ft. A couple of days ago, just for an experiment, I ran up a flight of stairs and didn't go over my AT! I'm not making a practice of that, of course. After watching this effect for a week and increasing my activity a teeny-tiny amount, I noticed that the effect tended to wear off as I did more and as the day went on. This would make sense of my body used up the amount of NAD I took in the morning, I suppose So... for the past couple of days I've been trying a new experiment. I know that my HR sitting in a recliner was consistently in the 90's. During the first 4-6 hours after taking NAD it is consistently in the 80's -- about 10 bpm lower. I decided to try taking more NAD when my sitting HR started to climb into the 90's. So far, within an hour of taking the NAD my HR will drop back about 10 bpm. I have no idea if any of this makes any sense biochemically, or even if the effect really is the NAD. This is hardly a good scientific study. Has anyone else had a clear effect from NAD?