Thyroid UK
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TSH Suppression Benefits and Adverse Effects

A topic often discussed on here. An excellent article by Dr. Jeffrey Dach in his latest newsletter. PR

"Mainstream endocrinology makes the assumption that a suppressed TSH indicates thyroid excess, and by definition, thyrotoxicosis. This is true for Graves disease and Toxic Nodular Goiter. In Graves disease with thyrotoxicosis, hypercalcemia from rapid bone turnover has been reported. (21,22)

However, for the vast majority of hypothyroid patients taking natural dessicated thyroid (Nature-throid- RLC labs) a suppressed TSH merely indicates adequate treatment dosage with full clinical benefit, and does not correspond with the clinical signs and symptoms (or laboratory findings) of thyroid excess."

11 Replies

Sensible article, thanks for posting.


Very interesting article thanks



I have had many previous heated discussions with doctors regarding this subject. As we know the bone is continuously being broken down and replaced by cells known as osteoclasts and osteoblasts. Each cycle of bone ‘turnover’ takes about 200 days and doctors believe excess thyroid hormone will hasten this rate of bone turnover.

It is also thought that a suppressed T4 and high T3 levels cause calcium to be leeched from the bones but I researched and spoke at length with Dr P about this as I ran a suppressed TSH for 3years on 125mg - 150 mg Levothyoxine.

He claims a suppressed TSH of less than 1 is perfectly safe as long as T3 is not too high. Reverse T3 may be measured to test levels of t4 (unused T3) in the blood stream.

Of course it is sometimes difficult to get these tests done but it is important for people to educate themselves and not be bullied by doctors. Simple articles such as this give us good amunitition.

Thank you for posting,



The problem is, as it is so often, that they are working from a very limited understanding of the system. That is not to say that there may not be some tradeoffs, but I believe most of us would be willing to pay the price for being able to live a "normal" life. None of the medications we have at this point duplicate what the body does naturally but some of them give us our life back. I'll settle for that at this point. My FT3 is 50% above the top of the range yet I have never experienced any 'hyper' symptoms. Of course that is assuming the FT3 test was one of the ones that are somewhat accurate. PR


If FT4 AND FT3 were regularly tested, it might be possible to distinguish between "suppressed TSH and within-range thyroid hormone levels" and "suppressed TSH and massively over-range thyroid hormones". With the former being fine and the latter being potentially a problem. But as soon as the buffers of suppressed TSH are hit, there is absolutely nothing that a TSH test can tell you about which state someone is in.

Even if FT4/FT3 were regularly tested, we have people with various forms of reduced sensitivity to thyroid hormone who would also end up with severe bone problems if adequately treated! After all, they can have very high FT3.


I'm alarmed by your last paragraph. I'm on T3 only treatment with occasional supervision from Dr P, but I've recently discovered that I may have reduced cell uptake and therefore need a larger dose than my current, 75 mcg, to eradicate my remaining (significant) hypo signs & symptoms. Surely, T3 has to be taken up at cell level to have any effect on bone density? Or have I misunderstood something (I've had 2 hours' sleep per night over the past week)?


I wrote that badly!

What I was trying to say was that in people with reduced sensitivity to thyroid hormone, even having a high FT3 probably does not cause any problems - so long as the level is appropriate for that person.


Phew! Thanks for clearing that up. :)


Quote from the article :

"Of course, we always monitor Free T3, Free T4, and Thyroid antibody levels, as well as monitor the patients clinical status."

This is science fiction or science fantasy - it's like reading about something happening in an alternate universe.

"It is common practice among endocrinologist to treat “euthyroid” Hashimotos patients with thyroxine (T4). “Euthyroid”, of course, meaning the TSH is in the lab reference range."

This quote is also from another universe. It may happen to a few lucky patients in the UK but for the vast majority it simply won't happen until their thyroid has been virtually destroyed and the TSH has risen. And this could take decades.

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FWIW, I read an article in pharmacists letter (went back to find it, its not there) which stated that low TSH is not a problem until it goes below 0.04. You might want to read what Janie Bowthorpe says on this subject:

As always, these docs who are obsessed with numbers are treating via lab test, not via how the patient feels. Ideally 1<TSH<2, but if you feel well (and I'm assuming you know what hyperthyroidism *feels* like) then a TSH below 1 is not important.


Thanks for posting ,have saved as some interesting points .But what beats me there is all this proof and still no change in the way thyroid patients are treated ,it as to make you wonder why.


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