You shouldn't take anything while fasting. You don't need any extra nutrient while juice fasting and you don't want to continue digestion. Thyroid and adrenal are both meds you can and should stop during a fast. Your glands are effected by what you eat and since juice fasting is completely healthy and sustainable, you don't need the glandular treatments.
Probiotics should be contniued after the fast, in mass amounts to help replace any good floura loss.
You should find a good juice fasting guide and follow. There are some listed in the book section of this forum.