VERY low TSH: I would appreciate some advice... - Thyroid UK

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alexcat profile image

I would appreciate some advice please as I am new to this site.

1. My functional medicine practitioner says my TSH is too low and I risk becoming Hyper. My Private Doctor whom I have been going to for 17 years for Armour says all is well as T3 and T4 are in a good place. I worry about bone health as too much thyroid meds can weaken bones???

2. Also if I were to lower my dose how could I do this? I take 2 gr Armour and 25 mcg Levothyroxine in the morning well before food.

3. Also can someone explain the Reverse T3 and ratio?

My symptoms are now few - slight low mood at times but I supplement with Melatonin (1 mg most nights) so it could be this? have managed to lose weight over the last 2 years to BMI of 27 which has lowered my TSH and also I was taking Armour with food ....!!

Blood Results (blue Horizons Lab) I am 62

Ferritin 312 (20 - 150) Subsequent NHS testing showed this as high but in reference range

TSH 0.005 (0.27 - 4.20)

T4 Total 109 (64 - 142)

Free T4 18 (12 - 22)

Free T3 5.02 (3.1- 6.8)

Reverse T3 33 ( 10 - 24) HIGH

Reverse T3 ratio 9.90 (<12 LOW)

6 Replies

Functional doctors seem to know as little about thyroid as the average GP/endo. Your TSH is low because you are taking T3 and don't need it anymore. TSH is a pituitary hormone that is produced to stimulate the thyroid when the pituitary senses that there is not enough thyroid hormone in the blood. If there is enough thyroid hormone in the blood, the TSH decreases. If you try to raise the TSH by cutting the thyroid hormone, the pituitary will only start producing it when if senses that there is not enough thyroid hormone in the blood, so you will become hypo again - it's what is called the 'feedback loop', and is obsolete when taking exogenous thyroid hormone.

The TSH has nothing to do with bones. It is high, over-range FT3 that causes damage to bones - and, obviously, if the FT3 is high, the TSH will be low, that is where doctors get confused. But, your FT3 is well within range - perhaps even a little low - so you are not risking your bones in any way. I would not advise lowering your dose unless you feel hyper-type symptoms.

And, on that point, having a low TSH does not mean you risk becoming hyper. That is ludicrous. You cannot become hyper because you are hypo, and an under-active thyroid cannot suddenly become hyper because the TSH is low. It's physically impossible. It doesn't work that way. You can, on the other hand, be over-medicated. But, you are not because your FT3 is not over-range. Your functional doctor should go back to med school for a refresher course on thyroid. :(

However, the fact that your rT3 is high, means that you have too much unconverted T4 in your system - unless your are on a starvation diet or have a virus, which will also result in high rT3. At a guess, I would say that you are a very bad converter. Your FT4 is high, and your FT3 is only just over mid-range, even on 2 grains of NDT. So, why the added T4? That's what's causing the high rT3. You don't need it. You would probably be better increasing your NDT, or adding a little T3 to your 2 grains of NDT, and cutting out the extra T4. High levels of rT3 are not good.

I'm afraid I don't know anything about ferritin/iron. Sorry. :)

alexcat profile image
alexcat in reply to greygoose

A big big thank you! I feel very much reassured.

I shall cut out the added Levo.

I am not sure I would be able to get hold of any additional T3 would I?

Perhaps also do the genetic testing as recommended on a different post...


greygoose profile image
greygoose in reply to alexcat

You can buy T3 on-line. Just post a new question asking people to PM you their trusted sources. :)

Ahh! Very many thanks!

Ferritin 312 (20 - 150)

Your ferritin (iron stores) is a bit high, but I wondered what conditions the test was done under.

According to the NHS :

Iron blood test

Iron blood tests are usually taken in the morning before you eat anything. You should also avoid taking iron pills or tablets for 24 hours before your test. Your body absorbs iron very quickly from food or pills, so this can raise your iron levels and affect the test results.

Source :

I did also find this from the American Hemochromatosis Society :

A simple series of blood tests which can be performed by any doctor or lab can indicate iron levels. They must be proper iron measures: Total Iron Binding Capacity (TIBC) together with Serum Iron. Divide TIBC into Serum Iron to get the percentage of transferrin saturation also known as % of saturation.. It is important that the serum ferritin is also performed at the same time and it should be done, if possible, while fasting. Refrain from iron pills for a week prior to the tests.

Source :

[My emphasis]

As you can see there are different opinions on how iron-related testing should be performed. Personally, I always do tests fasting and I stop iron pills for 5 - 7 days beforehand.

Whatever the conditions were, I think you should mention the high ferritin result to your doctor. Iron overload is NOT something to be casual about.

Thank you for this - I did not fast and eat quite a lot of red meat. I am watching this carefully as you say too much iron is not good. As soon as NHC doc saw levels were lowered on repeat test he lost interest.

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