It's great, it works for me as my system is very sensitive. I'm grateful to have found a bovine thyroid (glandular) that is better FOR ME (everyone is different) than any pharmacy/chemistry options. Several years ago I decided to get off of Rx meds and try a natural approach. I'd had thyroid cancer in 1988. It's not been easy to balance and thanks to Thyroid 300, I'm balanced. I don't recommend this way to everyone, as we are all different. I do recommend that we all be our own advocate and this .. .. .. the EXPERT with is the person having the experience. Get smart, be aware and TAKE CARE .. .. .. the best care of yourself.