I struggle with a low functioning thyroid that I've been taking medication for about 10 years. I am 47. I've noticed as I am getting older my energy levels have plummeted. I started taking this about 3 weeks ago and am very impressed with how I feel. I have more energy than I have had in years and am able to do a lot more without feeling sluggish. I highly recommend this if you struggle with a metabolism/energy issue. It's working.