Please can someone explain how Levo works again. I’m trying to understand what T3 and T4 mean and the conversion part?
Also why it is that you feel worse initially when you have an increase? I think someone said it’s something to do with out thyroid gets lazy and doesn’t work properly as it knows the Levo will do all the work? Something like that anyway
Thank you 🙏🏼
levo is T4. if things work out correctly, some of it converts to T3.
i think the simple explanation for starting to notice symptoms after an increase, is simply that isnt enough. Like feeding the hungry, a snack might give abit of relief short term, but long term, more food is needed.
i THINK
edited: Just re-read your qu
when you say feel worse initially after an increase, i think many of us might feel worse a few weeks after an increase, after perhaps feeling better initially. is that what you meant?
T4 is the main hormone produced by the thyroid or taken in the form of levothyroxine. It is stored by our body. The cells in our body cannot use t4. The body has to process t4 by removing an iodine molecule so it can be used. When t4 has an iodine molecule removed it becomes t3. This process is called conversion. The t4 produced by our thyroid is converted into t3 so our cells can use the hormones.
I always thought that we feel worse with an increase as our body is having to adjust to having an increase in hormones. Different hormones are involved but I liken it to the monthly sick feelings I had when I was young. Things are out of kilter and they take time to settle.
Thank you fir that. I always get that sick feeling like travel sickness? In fact it’s only now I look back and realise I don’t get that now since I’ve started on the Levo- interesting x
Iodine *atom* - not molecule - is removed. 
Some molecular diagrams here:
dropbox.com/s/5iz07xh8dr1n4...
Thanks Helvella - stopped science when I was 14 - totally arts and crafts here! Now what is the difference between an atom and a molecule? Will need to google!!
In general, an atom is the smallest unit of a chemical element. (Anything less than an atom is "sub-atomic".)
A molecule is two or more atoms bound together by some interaction.
Pure iodine will form molecules - two atoms (I) combine to make one molecule (I2). (Similarly for oxygen.)
(There are various other terms applied to groups of atoms in some circumstances - like ions or moieties.)
If the body has to remove the iodine from T4, why does T4 even exist?
Why can’t they do it for us and everyone just use T3?
Just something I was thinking when I read that reply. 🤔
In nature, because it acts as a store and is converted to T3 as needed. In pharmaceuticals, because it as cheap as chips to produce and can be taken only once a week if patient is not good at remembering to take tablets. Recognising that it doesn't work for everyone would mean a lot of red faces and eating humble pie - which doesn't happen with endos and the like.
As I see it (and could be so very wrong):
Distributing thyroid hormone in the form of the (at least mostly inactive) T4 means that our bloodstreams are carrying a safe payload.
Also, allows our tissues to take in some T3 (from the low levels in our bloodstreams) and also some T4 which can be converted within the tissue. Thus, each tissue can get some T3 from the bloodstream and some from local conversion. If some tissue needs more than other tissue, that makes it possible. (If it all went round as T3, there would not be the same scope for the different tissues adjusting their own T3 levels.)
Reminds me of explosives. Nitroglycerine was a very dangerous substance to transport. But Alfred Nobel mixed it with various other substances to make a stable, safe substance which could easily and safely be carried. But when it does explode, it is basically the same reaction!
Thank you x
When I had Levothyroxine increases I felt awful especially the first day after the first dose increase. I use to feel racing what felt like adrenaline out of control.
My last increase after 6 weeks I became very unwell. My cortisol dropped to 68 ( range 155-607).
The increase effected my adrenals. My adrenals couldn’t keep up basically, plus I later found out I was barely converting. When the decision by my GP was taken to increase Levothyroxine I was already at the top of the T4 blood range. But my TSH was over the range. No T3 test was done. What I needed was T3 medication not more T4 medication. In fact I now know I always needed both T4 and T3 medication as I did the DIO2 gene test and it was positive.
So although Drs make increases it’s not always that Levothyroxine actually needs increasing. And maybe that’s a reason people get ill on Levothyroxine increases. For me this was definitely the case.
Just to make the opposite experience known, I have never felt worse after a needed increase in dose. Currently on 125. Each increase felt needed and, when it arrived, I felt better for it. Mind, I have increased very slowly. Last two increases were 12.5 micrograms and I feel stable over long periods - years.
We are all different and some of us have a much easier time than others.
(If I were to take more than I need, I suspect I would not feel well on it.)
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