I began taking 1000 mg. spring, 2013. Then last fall he raised it to 2000 mg. so I did that until recently. Maybe that was too much for me? That's when my hair stylist began to say my hair was getting thinner.
I, like you, never felt any different taking it. Dr. W. mentions possible negative side effects like diarrhea or nausea and mentions positive ones like more energy and more relaxed. I know with NB it's not wise to expect changes by simply adding a supplement. But maybe in my case, the hair loss is "speaking to me!" That's also when I virtually stopped needing to shave my legs.