Thyroxine, Iodine and T4 - Please help me understand all this.

[jaxnbreeze]

I have just read that Levothyroxine is T4. I also think I have read that Throx. also contains a large amount of iodine. So does that mean that iodine contains T4. So, other than 'fillers', what active ingredients does Thyrox. contain that iodine doesn't. A retired GP friend of mine has mild hypo. and takes only kelp tablets. I was sub-clinical and have no anti-bodies so can I just take iodine or have I misunderstood the whole concept? Please help me to understand this conundrum.

[PinkNinja]

Hi.

T4 contains iodine but not the other way round. T4 is a hormone that is made in your thyroid but needs to be converted to be used. If you have hypothyroidism you will usually be prescribed levothyroxine which is synthetic T4.

Iodine is needed for your thyroid to produce thyroid hormones such as T4. If you don't have enough iodine your thyroid won't be able to produce the hormones therefore, under those circumstances, taking iodine could help sub-clinical hypothyroidism. If you don't have antibodies, it is certainly worth a try especially if you have fluoridated water in your area or don't get enough iodine in your diet.

I hope that helps a little. You may find the main Thyroid UK website helpful. There are pages about how the thyroid works, different treatments and also a page about supplements. Navigate using the purple menu down the left hand side of the page.

thyroiduk.org.uk/tuk/index....

Carolyn x

[greygoose in reply to PinkNinja]

Please, do not take iodine unless you have a test proving that you need it. You may not have antibodies now, but if you take excessive iodine, you may end up with them.

Iodine is not harmless, too much can cause as many problems as not enough. Get tested before taking it. I speak as one that KNOWS the damage it can do through first hand experience!

Grey

[Hidden in reply to greygoose]

What kind of damage can iodine do if you're taking thyroxine?

Can't you just take iodine instead of taking thyroxine?

[greygoose in reply to Hidden]

Thyroxine is the complete hormone, consisting of iodine and... forgotten the name... an amino acid. Bit woolly tonight! lol

Iodine on it's own is just a building block that the thyroid needs to make the hormone. However, if your thyroid is having difficulty making the hormone, because of Hashi's damage, or whatever, adding extra building blocks that it can't handle isn't going to help. The iodine will stimulate the thyroid saying come on, come on, get a move on! And the thyroid will try to keep up, but wear itself out in the process.

But it can be worse than just wearing out, it could, possibly, lead to cancer developping. If you have Hashi's, the symptoms become ten times worse, new symptoms appear. If you don't have Hashi's, the iodine could cause you to develope it.

And funnily enough, if hyper people take it, they can find themselves hypo!

Whereas, when you take thyroxine, the thyroid doesn't have to struggle anymore. It can relax. Thyroxine won't cure it, but it won't make it worse either (at least, not permenantly!).

The only reason to take iodine is if you have been tested and found to be iodine deficient.

At least, that is my opinion, but I know a lot of people disagree with. You only need a tiny amount of iodine in a life-time anyway, because it is recycled in the body. When T4 is converted to T3, an iodine molecule is released and returns to the thyroid to make more hormone.

Hope this helps, Grey

[psue in reply to PinkNinja]

I would suggest you take the time to read and understand how the thyroid works and how it makes thyroid hormone.

Very simplistically: Thyroid hormone is made up of tyrosine - amino acids formed when protein is broken down. Then Iodine molecules are stuck on to this protein. The number of iodine molecules is either one or two molecules of iodine making T1 and T2 resoectively- both are active hormones but with very short half life (dont last long).

Some of the two types of thyroid hormone (T1 and T2) then stick together to form either T3 or T4. Mainly T4 is released from the thyroid gland but a small amount of T3 and a great deal smaller amounts of T1 and T2 are also released from the thyroid gland which all together make thyroid hormone.

T4 is thyroxin and T3 is triiodothyronine; rarely do you hear people refer to T1 and T2, so its best to forget about them other than to know they stick together to form T3 and T4.

People also confuse things by referring to thyroid hormone collectively as thyroxine; this isnt acurate but is accepted thyroid 'slang'!

Thyroxine is the name used for T4 thyroid hormone; although the synthetic form of T4 is Levothyroxine (slightly different chemical make up to the natural hormone,) but often referred to as thyroxine; although each manufacturer will have its own brand name all synthetic T4 is Levothyroxine. This is the most common form of replacement thyroid hormone but is not beneficial to all hypothyroid patients.

T4 as I said forms most of the thyroid hormone released from the thyroid gland; this is a very weak form of thyroid hormone and must be converted to T3 in the body's peripheral cells. That is in the liver, gut, brain and kidneys and other cells too. This is referred to as deiodinase and selenium in the diet is essential for this action to take place.

Some hypothyroids are unable to convert T4 to T3 and despite taking T4 replacement will remain hypothyroid.

Armour Thyroid is one brand of desiccated thyroid replacement which is made from pigs thyroid glands and is pure and natural. It is a prescription hormone just as Levothyroxine is a prescription drug.