I wouldn't be so sure..... just because your numbers fall into the "normal" range doesn't mean it's the right range for YOU. My doctor explained that to me years ago. He told me that we should find at what level "I" feel the best at, and try to stay there, rather than keep me in the range the labs consider "normal". And I can tell you from years of experience that every time my numbers fluctuate, I go through about 6 weeks of side effects, the biggest of which are anxiety-related. Such a fun auto-immune disease!