is it safe to take thyroid support supplement when my thyroid is healthy?

I have a family history of thyroid disorders. My mom had thyroid cancer and my father had hyperthyroid. I had a goiter 3 years ago. It was drained and turned to be benign. My recent blood work indicated that my thyroid is functioning normally. However, I have been feeling a bit sluggish and have put on over 10 pounds in the last 5 months without changing my eating habits at all.
Any advice is appreciated!