My wife uses this product because her underactive thyroid leaves her lethargic and sleepy. It does a remarkably good job in helping her feel more normal. She takes one capsule first thing in the morning on an empty stomach, and a second one mid-afternoon. She feels more energy and more mentally clear. Episodes of fatigue and weepiness have been banished since beginning this regimen. For us, it's been a lifesaver! No bad side effects, as far as we can tell. I believe that nutritional supplements saved my life. I've tried a lot of products, and I know what works and what doesn't.