Normal TSH, Low Thyroid Hormone. Is This Rare?

On a recent forum post, there was a question about a normal TSH and low thyroid hormone. This person wanted to know if this is common and should they go to another doctor. Here was my reply:

"Great question...and it is not a rare occurrence.
Here are some things you need to first know, and then better assess your situation.

What was the level of your TSH? Normal TSH means different things for different doctors, and labs have different ranges for "normal" as well. Also remember that "normal" is based on averages from a large population of people and abnormal is people that are a certain percentage outside of that. What really matters is what is normal TSH is for you...those other numbers are just a good guideline.

There are internal and external influences that can affect your hormone levels. For instance, woman begin to get worse symptoms when they have a flux in their estrogen (menstrual cycle) which influences their thyroid hormone production and utilization. The same can be said for people during winter months, or if they have a problem with their detoxification system, or if they are eating a lot of soy (there are tons of "or ifs"). The key to remember is this: Lab test are a snapshot of how your body was doing at that specific point in time. It can be completely different hours, days, and weeks later.

And you are right, going just by TSH is a very poor way to asses the situation. Even if it is low, it is still a poor way to asses the situation. There are too many questions that need to be answered to make a confident diagnosis and treat one way or another.

I would find another doctor (you should thank your original doctor for referring you once s/he realized it was out of his/her realm), but go into it prepared. There are plenty of studies that show a person who understands their condition will have significantly greater improvements over those who do not. If you know ahead of time the right questions to ask, you can sort of "interview" your doctor to make sure s/he knows how to properly manage the situation. You will be surprised at who knows what."

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