I’ve just read an interesting thread about dosing for T3. I didn’t want to hijack the discussion so thought I’d start again and outline what I see as a problem with getting a combo dose right.
Like many on here I have continuing and irritating issues with endos who regulate against TSH primarily and so are constantly trying to reduce my dose of thyroid hormone. Until recently I’ve been getting both T3 and T4 as well as regular blood tests. But this has been ‘managed’ by me. Essentially I leave out taking a dose before a blood test, but because I take my meds when I wake around 4 am the gap between my last dose and the blood draw can be as long as 28 hours.
I know from information on this site that T3 has a very short half life and that even the T4 levels after such a delay will be well reduced. This sort of works in my favour when I take the results to the endo as the levels of both T3 and T4 are near the bottom of the range. She has nevertheless consistently reduced my overall dose. Before I was on a combo dose, I took 150 ug levo, I seemed ok for a while on 75 ug levo + 12.5 cynomel. However recently....well on and off for about a year I have been getting palpitations. Recently they have become more pronounced and I mentioned them to my endo who immediately removed the cynomel altogether leaving me on 75 ug levo. This was done even though my last blood result showed my TSH had risen from under 1 to over 3 in the space of 6 months.
I feel I need to do bloods that will give me a truer picture of what’s in my system and it might be better to know what the peak values are if I am to go back down the road of self medicating.
So I have a number of questions for people who know these things.
Is it true that palpitations can be due to under medicating as well as over medicating?
If one takes blood 5-6 hours after a dose of T3 + T4 will it show peak blood concentrations of both ?
Is it better to dose according to the peak concentrations of both T3 and T4?
I take temperature and pulse daily and I can’t get my body temperature above 36.2 on my current dose which I’ve increased to 100 ug T4 and 12.5 ug T3. If this continues how long before I increase again? (I’ll get a blood test in about 4 weeks time)
I know nothing about reverse T3....is it an issue? What happens and how do we know ?
How does TSH vary over 24hrs....does it go down immediately after a dose or is there a delay? I had assumed TSH is very slow to respond to dose changes.
There’s a lot here I know, but just wanted to pick the brains of those who have worked all this out the hard way.
Btw I take B12, complex B, selenium, zinc, magnesium, vit C and K2 and mostly my vit levels are ok although I don’t check them that often.
Many many thanks in advance for any helpful insights
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GonzalezGirl
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If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 7 days before any blood tests, as biotin can falsely affect test results
Bloods should be retested 6-8 weeks after any dose change
Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .
Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)
If/when also on T3, make sure to take last third or half of daily dose 8-12 hours prior to test, even if this means adjusting time or splitting of dose day before test
Looks like your endo doesn’t understand...TSH is largely irrelevant When taking levothyroxine plus T3
The most important results are ALWAYS Ft3 followed by Ft4
Dropping levothyroxine by such large amount from 150mcg to 75mcg was highly likely far too much ....unless Ft4 was extremely over range
Amount Levo is reduced depends on where Ft4 is before adding T3
Typically if Ft4 is high, but within range levothyroxine reduced by 25mcg and 2 x 5mcg T3 added.
Bloods retested after 6-8 weeks
Suggest you include getting vitamins tested as you are now likely very under medicated
Is it true that palpitations can be due to under medicating as well as over medicating?
Absolutely, yes. Many symptoms can be of both under and over-medication. Personally, I only get palps when I'm under-medicated.
If one takes blood 5-6 hours after a dose of T3 + T4 will it show peak blood concentrations of both ?
Not sure about that one. I thought the peak was about 2-3 hours after taking a dose.
Is it better to dose according to the peak concentrations of both T3 and T4?
No, because the peak doesn't last long. You want to know your normal circulating level of both, which is why we recommend leaving a gap of 24 hours for T4 and 8-12 hours for T3.
I take temperature and pulse daily and I can’t get my body temperature above 36.2 on my current dose which I’ve increased to 100 ug T4 and 12.5 ug T3. If this continues how long before I increase again? (I’ll get a blood test in about 4 weeks time)
You might never get your temperature above that on any dose, because your thermostat is broken and may never rise. It's really not a good basis for increasing or decreasing a dose.
I know nothing about reverse T3....is it an issue? What happens and how do we know ?
No. It's a safety valve. It doesn't cause symptoms, or block the actions of T3 or cause poor conversion or clog up the T3 receptors as used to be thought. Testing it is expensive and doesn't give you any useful information - it will tell you if it is high, but not why. And, there are many, many reasons for excess rT3 (please note that you will always have some in your system), and only one of these reasons has anything to do with thyroid.
Not sure what else you want to know with the second part of that question, but rT3 only stays in the body for a couple of hours before being converted to T2. How do we know what?
How does TSH vary over 24hrs....does it go down immediately after a dose or is there a delay? I had assumed TSH is very slow to respond to dose changes.
TSH is highest up until about 9 am, and drops throughout the day. Which is why we recommend testing before 9 am. Taking a dose of levo has no effect on TSH. It is very, very slow to react to an over-all increase in dose. It does not react to individual doses.
Many interesting points. Very helpful thanks. One thing I don’t understand is how my TSH went from 0.66 to 3.08 in six months ( range 0.27-4.20) on the same dose. I do have Hashimotos and believe there are such things as ‘flare ups’. Would this account for it? I was also during this period trying to do the Ketone diet and ate almost no carbs. If it was a flare up, I didn’t notice any ‘episode’ of poor health. I’ve just become increasingly aware of palpitations / sometimes breathlessness and very recently becoming more symptomatic....muscle aches etc.
I’ve upped my dose to 100 levo but should I consider increasing my T3 before I get tested in about 4 weeks? T3 in May was 3.8 (3.1-6.8) and 3.7 in October. However these are bloods taken around 26 hours after a dose. For info my T4 in May was 12.5 and in October it was 14 (12-22).
I’ve been very wary about pushing my doses up with the palpitations but feel this has adversely affected my judgement. A dentist recently commented on how a section of my jaw is losing bone density and causing teeth to come loose. Do I take this to be another sign of under medication, particularly with T3?
Hope you don’t mind all these questions, you seem to be very knowledgeable.
Hashi's doesn't have 'flare ups', not like arthritis or something, it has 'flares', so called. But that's a very bad name. Here's a brief explanation of how Hashi's works:
Hashi's is an autoimmune disease, where the immune system attacks and slowly destroys the thyroid. It is diagnosed by testing Thyroid Peroxidase (TPO) antibodies and Thyroglobulin (Tg) antibodies.
Contrary to popular belief, it is not the TPO/Tg antibodies themselves that attack the thyroid:
"When lymphocytes infiltrate the thyroid gland, mistakenly taking it for a foreign bacteria invader, they damage the thyroid gland and release thyroid peroxidase &/or thyroglobulin into the blood stream. These don't belong outside of the thyroid gland so antibodies are developed to mop them up.
The antibodies are a result of the attack on the thyroid gland, the antibodies don't cause the attack."
After every immune system attack on the thyroid, the dying cells release their stock of thyroid hormone into the blood stream, causing the levels of the Frees to shoot up - FT4 to around 30 something, FT3 around 11/12 - and the TSH therefore drops to suppressed.
There is no knowing how long these high levels will persist, but eventually, they will drop by themselves as the excess hormone is used up or excreted, and not only will you become hypo again, but slightly more hypo than before, because there is now less thyroid to make hormone.
(NB: A Hashi's 'hyper' swing is not true hyperthyroidism in that your thyroid is over-producing thyroid hormone. It's physically impossible to 'go hyper' if you are basically hypo. The thyroid cannot regenerate itself to the point of over production of hormones - or even normal production. Very few doctors appear to know that.)
Therefore, it's very important that your doctor does not reduce your prescription, because you’re going to need it again! If you start to feel over-medicated at that point - some do, some don't - the best thing is to stop levo for a few days, then, when you feel hypo again, start taking it again. It's very important to know one's body, and how it reacts.
There is no cure for Hashi's - which is probably one of the reasons that doctors ignore it - apart from the fact that they know nothing about it, of course!
However, between the 'hyper' swing, and the descent back into hypothyroidism, there can be a phase - quite a long one, sometimes - of normality, where the person is neither hypo nor 'hyper'. This is where people sometimes start talking of having 'cured' their Hashi's, by whatever means. But, it doesn't last. Eventually, you will go hypo again.
But, there are things the patient can do for him/herself to help them feel a bit better:
a) adopt a 100% gluten-free diet. Hashi's people are often sensitive to gluten, even if they don't have Coeliac disease, so stopping it can make them feel much better. Worth a try. Some say that going gluten-free will reduce antibodies – I’ve never seen conclusive proof of that, but, you should be aware that even if you were to get rid of the antibodies completely, you would still have Hashi's, because the antibodies are not the disease. It is not the TPO/Tg antibodies that do the attacking.
b) take selenium. This is not only reputed to reduce antibodies, but can also help with conversion of T4 to T3 - something that Hashi's people often find difficult.
c) the best way to even out the swings from hypo to 'hyper' (often called Hashi's Flares, but that doesn't really sum up the way it works) is to keep the TSH suppressed. This is difficult because doctors are terrified of a suppressed TSH, for various false reasons, and because they don't understand the workings of Hashi's. But, TSH - Thyroid Stimulating Hormone (a pituitary hormone) - tries to stimulate the thyroid to make more hormone, which also stimulates the immune system to attack. So, the less gland activity there is, the less immune system activity there will be, meaning less attacks, gland destruction slowed down and less swinging from hypo to hyper and back.
If you felt worse on a no-carb diet, it was probably because it negatively affected your conversion of T4 to T3 - you need carbs to convert - so, you went more hypo.
I’ve upped my dose to 100 levo but should I consider increasing my T3 before I get tested in about 4 weeks?
If you increase your T3 now, you won't be able to test in 4 weeks. You need to be on the same dose for 6 to 8 weeks before testing. Wait til after the test.
T3 in May was 3.8 (3.1-6.8) and 3.7 in October. However these are bloods taken around 26 hours after a dose.
In that case, it is a very false low FT3. You should only leave 8 to 12 hours between your last dose of T3 and the test. So, you have no idea what your FT3 really is, so you don't know if you need to increase it.
A dentist recently commented on how a section of my jaw is losing bone density and causing teeth to come loose. Do I take this to be another sign of under medication, particularly with T3?
Not necessarily. It could be due to nutritional deficiencies.
Apologies to Gonzalez Girl for sort of hijacking her thread a bit but I am also about to test and have questions along similar [but slightly different] lines and would appreciate some advice.
I am self treating with T3 for ISTH. My questions concern timing of the testing.
Firstly, I am currently on 50mcg of T3 but over the last couple of weeks have had to adjust that dosage downwards to get to a position where I am "comfortable". For the time being that seems to be 50mcg. I made my last adjustment yesterday, reducing by 6.25mcg. Does this mean I have to wait at least 4 weeks before I can take tests to measure my blood values?
Secondly, regarding the time of day the test should be taken and the relationship between the time the T3 dose is taken, I take mine in a window between 4 and 8am [depending on bathroom break]. That being the case, if I took my dose in that window I wouldn't be able to leave 8-12 hours before I would do my test [before 9am]. Would I therefore be better to miss that day's dose (which I can do without suffering ill effects), do the test and then resume dose in the next dosing window?
No, it means you have to wait at least six weeks before testing.
If you left more than 8 - 12 hours between the last dose of T3 and the blood draw, you would get a false low FT3. And, whilst I'm not quite sure what you're suggesting, there, it sounds like you would be leaving more than 24 hours, so a very low false low.
Who are these labs for? Are they for yourself or a doctor? If they're just for yourself, then when you have the blood draw is less important than the time of your last dose. Having the blood draw before 9am is so that the TSH is at its highest, because that's all doctors tend to look at. You, yourself, know that TSH is going to be suppressed, anyway, on 50 mcg T3, so you're not going to be shocked by that. And T3 itself doesn't vary quite so much through the day as TSH. So, I would say, take your T3 at the normal time, then take the blood sample 8 to 12 hours later. That way, you would get an accurate reading of your normal circulating T3, which is the most important number.
Thank you. This test would be just for me (and to post results on the forum) as I haven't had any tests done since I first began to take T3 in January, so I hear what you are saying re less importance being attached to the TSH value given that I am taking T3. That being the case, then I should take my T3 dose in my 4-8am window and then do my test 8-12 hours later, so that if, for example, I was taking my dose at 5 am then I would need to be doing my test in the region of 2pm or thereabouts .
Regarding the 6 weeks after changing a dose before testing - does that apply to both upward and downward adjustments?
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