Part 4: Can taking thyroid hormone kill or damage the thyroid gland?

An example of thyroid science naivety and quackery4


In the video analyzed in this series (10), this man generalizes too far about all pharmaceuticals being harmful interventions.

He thinks taking thyroid hormones, just because they happen to be a medicine, can actually kill or damage the thyroid gland (14:27 to 15:25).

But thyroid hormone medications are not like other man-made chemical pharmaceuticals. You have to understand their structure and function to see this.

By examining these medicines and our human responses to them, we can see that ANY prejudice against the pharmaceutical source is illogical and harmful — even prejudice against one pharmaceutical source versus another.


(See part 5, which examines this scientific topic. “All thyroid meds are bioidentical, but individual response varies widely“)

To summarize, all thyroid pharmaceuticals yield thyroid hormone molecules in bloodstream that are bioidentical to naturally-produced thyroid hormones in human beings.

The differences between pharmaceuticals are not so much due to their thyroid horomne content, but are mainly due to individualized responses to a variety of doses and T3/T4 thyroid hormone ratios. Therefore both dose and ratio must be safely and effectively adapted to the unique needs of the patient.


Leaving behind for now the real damage to the body that can result from either chronic underdose or chronic overdose or an inappropriate ratio of T3 to T4 in blood, let’s use our knowledge of thyroid pharmaceuticals to answer this question:

Could having an optimal level of thyroid hormones in circulation from a pharmaceutical source ever damage living thyroid gland tissue?

Given that these medications contain hormones that are bioidentical in structure and function, I can find no scientific theory or evidence that they ever could.

The thyroid is helping to produce and convert these hormones. Healthy thyroid glands happily coexist with the hormones they secrete and convert.

In a state of health, do normal levels of T3 and T4 in bloodstream make a thyroid gland lazy? No.

Why would they?

A thyroid gland is not like a muscle that becomes weak if you don’t use it.

Even if you don’t use your sex organs, your ovaries or testicles won’t die because of disuse.

We know people on thyroid hormones who have a little TSH can still have a partly functioning gland that secretes at low capacity and continues to convert thyroid hormone as blood containing T4 and TSH flows through the gland. (30, 30b)

If you take people off thyroid hormone, they generally go back to the same level of thyroid hormone production they had before starting it, unless their thyroid tissue has been further killed off by autoimmune processes or other problems while on meds.

You simply can’t slow down living thyroid tissue from functioning unless you directly interfere by using medications that operate in completely different ways from thyroid hormones, such as meds that suppress TSH or anti-thyroid medications like propylthiouracil (PTU) that hinder hormone synthesis.


See the reference list for all 5 posts in this series: “REFERENCES for “Thyroid science naivety and quackery” posts

One thought on “Part 4: Can taking thyroid hormone kill or damage the thyroid gland?

  1. There is evidence that taking external tesosterone reduces in irreversibly secretion of natural testosteron. What if there is similiarity with thyroid gland? After all they are both hormons.

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