A recent blood test indicated that my thyroid isn t producing enough thyroxine but I don t have any major symptoms. I m 72 years old, at my ideal (steady) weight, I m not on any medications, my memory is good and my energy level is acceptable. I have been scheduled to retake the blood test next month to make sure it s not an error. However, I m a vegan and I suspect my intake of niacin may be too low and I understand niacin is needed to produce thyroxine. Do you think I should also be tested for niacin? Or should I just start taking a small dose like 50mg. If the test comes back showing the same result and I don t take medication for it, can there be adverse consequences? I can t see taking a drug, with possible side effects, for something that s not producing any major symptoms.