This is literally the only T3 that I will use for weight loss. I’ve used several UG and Pharma brands, and this is the best quality and is consistent, as I’ve been using it for about 3 years now to keep weight in desired range and to prevent metabolic degradation during bouts of low calorie intake. Active form; so better results than Synthroid (T4) and I don’t get the nasty headaches when using a higher dose like I do with most of the UG forms. Will be continuing to purchase! Great price & thank you!