Low TSH

[patience123]

What does it mean when the TSH is low but T4 and T3 are normal?

[Cara]

It means normal to overactive thyroid.

TSH is released from the pituitary gland to stimulate the thyroid gland to produce more thyroid hormone. High TSH means that something may be going wrong with the body's feedback system that stops the pituitary from releasing TSH when there is enough thyroid hormone (T3 & T4) in the body.

Most people confuse this because you think that low is "bad," but if T3 & T4 levels are normal then there is probably nothing wrong. However, if you suspect something then by all means speak to your doctor.

We deal with this all the time in animals, so my knowledge is limited to veterinary medicine.

[Kristy]

Define "low TSH" and "normal T3 T4" Do you have your test results handy? The range levels used to test these hormones are not very accurate.

[patience123]

I don't have my results on me, unfortunately. I just know that I have a low TSH because my aunt is a nurse, so she looked up my results in the system. So she said that everything showed normal except TSH is low. Is there such thing as it being too low? :scratch:

[strongchick]

I would ask what the actual values are. Low TSH doesn't necessarily mean hyperthyroid.

[Kristy]

Originally posted by patience123@Jun 1 2006, 05:00 PM
I don't have my results on me, unfortunately. I just know that I have a low TSH because my aunt is a nurse, so she looked up my results in the system. So she said that everything showed normal except TSH is low. Is there such thing as it being too low? :scratch:
What strongchick said. You need to see the actual values.

If your free T4 and Free T3 levels are in a good range, then your TSH doesn't mean much.

If you're on thyroid meds, its normal to have a supressed TSH.

[patience123]

oh ok :) thanks!!!
I am on thyroid meds. So I'm hoping it's all good :D We'll see what the Dr says.

[Kristy]

Originally posted by patience123@Jun 1 2006, 07:20 PM
oh ok :) thanks!!!
I am on thyroid meds. So I'm hoping it's all good :D We'll see what the Dr says.
Since you're on meds, don't worry about your TSH at all!

If its any bearing, my TSH is 0.021 on meds and I am not hyperthyroid.

T3 and T4 levels are the most important thing to focus on if you are hypo. Just keep in mind that many doctors do not understand this, and will think your levels need tweaking. If you have optimal T3/T4 levels, don't drop your med dosage!

[tenacious]

I think that my doc usually just checks my TSH, which is around 0.8. What are normal T4 T3 levels?

[Kristy]

Originally posted by tenacious@Jun 2 2006, 03:56 AM
I think that my doc usually just checks my TSH, which is around 0.8. What are normal T4 T3 levels?
No offense, but your doc sucks. Checking only a pituitary hormone when looking for a thyroid issue is negligent.

"normal" is subjective. It depends on the ranges your labs use and when you feel your best. But generally people that have ranges in the lower ends usually need some sort of extra thyroid hormone.

So if your lab ranges are something like:

FT4 range: 0.8 - 1.8
FT3 range: 2.3 - 4.2

and you're .9 T4 and 2.3 T3, you're probably hypo. But there are a huge amount of variables along with this.

[Inatic]

optimal free T3 and Free T4 should be MIDrange or higher.

If your taking a med that contains either or both, your dr SHOULD be testing the FREE's.

and judging from .8, if kristy's ranges are correct.. your undermedicated. Have your dr run Free t3 and free T4.