How do you Determine Normal TSH Levels?
How do we know what is best when it comes to determining an optimal thyroid level? I want to map out three approaches that can help guide our thinking on this subject…
For starters, let’s talk about the main values that are going to be relevant here. We have:
- Reverse T3
- T3 & T4
- Thyroid antibodies
As part of today’s discussion, I will mainly discuss the markers of thyroid output (as listed above). That said, we will not discuss reverse T3 in too much detail. I have discussed it before on my blog, though, and would recommend diving into the topic here.
T3 and T4
As far as T4 and T3 are concerned, we also need to quickly hit on the ideas of ‘total’ and ‘free’ levels of T4 and T3. When options are available for testing, I would typically recommend the ‘free’ version of testing.
But, I don’t mean free because it costs nothing! A free test will determine the levels of hormones that are ‘freely active’ in the body. It is a more accurate reflection of the hormone that is available to someone in their body (rather than inactivated and inaccessible).
Last, but certainly not least, we have TSH. It is always important to remember that TSH is a backward marker – the more your body lacks thyroid, the higher your TSH score. The more thyroid you have, the lower your TSH score.
Essentially, your TSH score is the rate at which your pituitary is asking your thyroid to work and create more thyroid hormones.
There is a great deal of data saying that, within the normal range, there are differences depending on which end of “normal” you find yourself.
Most labs now call the normal range 0.45 – 4.5 – or 0.4 – 4.5. Those are the typical numbers you will find when it comes to the higher and low ends of the range.
Data has found that those who are on the lower side, generally tend to do better. But, what does better mean? Better can look like:
- Less risk of thyroid enlargement
- Less risk for weight problems
- Less risk for heart disease
- Better energy levels
- Better quality of life
A lot of things end up being better when that TSH score is on the lower side of normal! This also differs by age, gender, population, and pregnancy status. But, for most adults, that range is going to be around somewhere 0.5 – 2.0.