Definitely works. I have more vitality and energy, which is something I have struggled with for years. I have tried everything from regular exercise, quality sleep, very healthy diet, and though those did help a bit, I still struggled with overall energy throughout the day. Not even caffeine would work. Then I began to read up on this compound and how those with hyperthyroidism have low levels of this nutrient necessary for energy production. I took 2 capsules of this a day, for I've read that it's good for beginners to do that and then to maintain blood levels with 1 capsule a day after those two weeks, and I have never had this much energy before. Even caffeine effects me now, which has never happened before. If you're struggling with energy, and diet, sleep, and exercise aren't helping, try this out. It's highly worth it