Synthroid vs Cytomel's effect on TSH Suppression

[Joyya]

For the last 6 weeks I haven't felt well, but it took until 4 days ago to realize that the individual symptoms that have been having were related and were a reappearance of hypothyroid symptoms.

I met with my MD today and told him that a few days ago it became clear that the cluster of 6 or 7 symptoms that I now have are all related to my thyroid. I am very, very fortunate that my doctor is very supportive.

I told him for the last 4 days, I increased my Synthroid from 88 mcg to 100 mcg to see if I felt better, leaving my Cytomel at 5 mcg x 2 times per day. I told him I am feeling much better today. He was very pleased, and wrote me a prescription for Synthroid 100 mcg, but wanted me to go for lab tests, to see if my TSH is much more suppressed. He is fine with it being below the cut-offs, just not crazy low.

There were no 9 AM lab tests available for weeks, and the first one I could get was this coming Monday in the afternoon. So here is my question:

If I don't want TSH to be overly suppressed between here and there, can I only take 5 mg Cytomel per day (instead of 10 mcg Cytomel per day) along with the 100 mcg Synthroid in the morning?

That is, which has a quicker effect on TSH levels, Cytomel or Synthroid?

Thanks!

Joyya

[Charlie-Farley]

Hi Joyya

Sorry you have been feeling out of whack. I think it is impossible to predict what a TSH will do with any certainty, especially on combo. Reading on here I have the impression TSH will be significantly lower on combination and probably the only way you can keep the TSH in play is to under medicate. This is what brings many of us here - being unable to satisfy the TSH targets of various well meaning doctors and actually getting a therapeutic dose of thyroid hormones. TSH is a false prophet.

There are two references that might be an interesting read for you if you haven’t seen them before.

thyroidpatients.ca/2019/10/...

frontiersin.org/articles/10...

From my reading over the last 3 years, in my spare time, I have come to realise the current understanding is nothing of the sort and fatally flawed.

The fact a paper that has been widely referenced in discussions of low TSH in people with HypOthyroidism is actually a paper on subclinical hypERthyroidism (you really can't make this 'stuff' up). There should have been a study to see if the hypothesis was sound. Nothing - otherwise there would be a different paper being referenced. Assumptions, extrapolations and ridiculous contradictions litter the field of thyroid related endocrinology. Yes there is some good stuff out there but it seems to have been held on the periphery.

We really do have to dig out the truth and self-advocate.

[Joyya in reply to Charlie-Farley]

Thanks. I have been doing a lot of reading the last few years, too but unable to determine if my idea may work (see below).

I am thinking of NOT taking the second 5 mcg of Cytomel for the next few days before the blood test with the assumption that it may help offset the additional suppression from the increase in Synthroid over the last few days and between now and the tests on Monday.

Can anyone answer that question?

Thanks.

[greygoose in reply to Joyya]

I'm really not clear what your question is, what it is you want to do. What do you mean by 'offset'? Whatever you do between now and Monday is probably not going to have the slightest effect on the TSH because it doesn't move that fast. And just reducing your T3 by 5 mcg probably wouldn't have any long-term effect either.

Also, as your blood draw is in the afternoon, the TSH is going to be naturally low, whatever you're taking. So, all in all, your hopes of having an unsuppressed TSH on Monday afternoon are doomed to faillure, I reckon. And there's a very good reason for this: you don't need it anymore. Why would your pituitary make TSH when you are not only taking adequate exogenous thyroid hormone, but you're not even reliant on conversion any more. Next question: why don't endos understand this?

[Joyya in reply to greygoose]

Thank you for your reply.

First question: based on what you have said, the increase in Synthroid for 7 days before having the blood work done should have no effect on TSH?

Second question: how long will it take for symptoms to resolve if I have only noticed feeling out of whack for 6 weeks. I've got significant mucin accumulation in my legs again and swollen ankles. Feeling cold, having blue lips and dry skin is less of a rush.

This is my GP — who is super supportive. He gave me a prescription based in my symptoms without labs, but is requisitioning the labs mostly to cover his decision.

Thanks!

[greygoose in reply to Joyya]

First question: based on what you have said, the increase in Synthroid for 7 days before having the blood work done should have no effect on TSH?

None whatsoever. But why do blood work only 7 days after an increase? It won't give you any useful information because it's too soon to see any change in TSH or FT3. And, although the FT4 might rise a bit, that won't be its final result on the increased dose. That could change in the coming weeks.

Second question: how long will it take for symptoms to resolve if I have only noticed feeling out of whack for 6 weeks.

Absolutely no idea. Impossible to say because these things are totally unpredictable and vary from person to person. Hypothyroidism is a ver personal disease.

I'm afraid your GP knows very little about thyroid. Be very wary of anything he says.

[Joyya in reply to greygoose]

Thanks. Your answers are helpful and I appreciate your reply. I

I am very grateful to have a GP who prescribes meds based on my report of symptoms and to prescribe both Synthroid and Cytomel. He knows he is no expert. Requesting lab work is really more to cover himself for prescribing before running labs.

I appreciate your help!

Have a good weekend.

[greygoose in reply to Joyya]

Yes, it's great to have a doctor like that. But, he can't have it both ways. He cannot prescribe based on symptoms and still fret about the TSH. The two are incompatible.

[Joyya in reply to greygoose]

I think he's just covering his backside. Prescribing based on symptoms in the absence of labs could put him in difficult situation. He let's me analyze the percentage through the range of T3 and T4 and is willing to maximize those, within the cost text of TSH being detectable.

Two more questions.

1. How responsive is free T4 levels to an increase in Synthroid. After a week should I expect they will have risen measurably, or at all?

2. How responsive is free T3 levels to a decrease in Cytomel? After a few days, should I expect they will have changed much, or at all?

Thanks!

[greygoose in reply to Joyya]

1. How responsive is free T4 levels to an increase in Synthroid. After a week should I expect they will have risen measurably, or at all?

Difficult to say because I doubt many people have ever tested it after only one week. And, probably, like most things hypo, it varies from person to person.

2. How responsive is free T3 levels to a decrease in Cytomel? After a few days, should I expect they will have changed much, or at all?

Probably quite responsive because T3 has a half-life of only about 24 hours. So, if you're not topping it up every 24 hours, it will probably drop quite quickly.

If you're taking 10 mcg a day at 8 am, but 8 am the following day, you will have 5 mcg left, minus whatever gets into the cells (and that definitely varies from person to person).

So, then you add in 10 mcg more and you have 15 mcg.

The following day you will have about 7.5 mcg left, and you add in another 10 and you have 17.5 mcg...

And so on.

Reducing it will go even quicker. If you start with the 17.5 mcg, the following day you will have 8.75 mcg but you only add in 5. So, that's 13.75 mcg

The following day you have approx 6.8 mcg and you add 5, that's a total of 11.8 mcg.

The following day you have 5.9 mcg, you add in 5 and it's only 10.9 mcg. Etc. Etc. Etc. (Please don't check my maths, it's probably all horribly wrong, but it's half past three in the morning and I'm no mathmatician at the best of times. But, you get the drift. )

[Joyya in reply to greygoose]

Thanks. I truly appreciate your informed answers. I promise I won't check your math!

[greygoose in reply to Joyya]

🤣

[Joyya in reply to greygoose]

I lied. I have another question. If I am having blood drawn at 2:00 PM, do I any meds that morning (6 AM)?

[greygoose in reply to Joyya]

You need to leave a gap of 24 hours between your last dose of levo and the blood draw. And a gap of 8 - 12 hours for T3. So, if your blood draw is at 2 pm, you're going to have to recalculate the times you take your hormone.

[Joyya in reply to greygoose]

Thanks so much. I won't ask any more questions tonight. Please get some sleep!!

[greygoose in reply to Joyya]

Wish I could get some sleep! It doesn't come easily at the moment, what with one thing and another - and I sincerely believe that one thing is flue and another is covid! Both at the same time! 😂

[Joyya in reply to greygoose]

Ay yay yay. I'm sure you've read about some supplements that can help. Hang in there! Take care!

[greygoose in reply to Joyya]

Well, fingers crossed, I think I'm over the worst. But it involved a lot of sleeping, and I'm all slept out, now. Been taking my vit D and vit C, and honey and ginger... but I wouldn't really say any of it helped. The thing just has to run its course. Sigh.

[GlowCoach Administrator]

Just saying, but ideally one would do a blood test before making any changes to your dose.

Once you have changed your dose you won't be able to tell where your results are for 6-8 weeks as they will be inacurate, so in many ways your upcoming test will be pointless.

[Joyya in reply to GlowCoach]

Thanks. My doctor knows to test 6 weeks later to see blood response to medication adjustment, and also to test labs before adjusting. I think he's running these to protect himself legally, as he prescribed meds based on my self-report without any labs gor 8 months.