A ramble concerning Reverse T3 ratio/ DIO2 polymorphism and dosing.

[MacG]

Have noticed in other posts that testing RT3 is not recommended as "you will know this from the FT4 and FT3 results". I am presuming that if RT3 is high and the cause of that is thyroidal the FT4 result will be high and the F T3 result low? But then if RT3 is blocking T3 at cellular level you cannot know this from a blood test?????

I fully appreciate that there are reasons OTHER than thyroid, in short, a variety of other body stressors, that might cause RT3 to be high and suspecting this to be the case, I did recently order the Blue Horizon Platinum Test. (About 18 months ago under the direction of a functional health doctor I had the same test which showed that my RT3 was near the top of the range: 21 (10-24) and flagging up the Reverse T3 ratio as low 12.65 (Normal >15). For reference, at that point my FT4 was 17.3 (12-22) and FT3 was 4.08 (3.1-6.8).

Things have improved in terms of the RT3: the test I took a couple of weeks ago is showing RT3 as 14 (10-24) and the ratio as 16.37 (Normal >15). I have, however, come across information that says that an ideal ratio is higher than 20.

RT3 ratio aside, what the same test results show however, is that my FT4 -13.2 (12-22) and FT3- 3.52 (3.1-6.8) are hardly optimal. In fact, lower than they have been for several years and not helped by the fact that about 6 weeks ago I had to deal with a GP in the practice other than my usual GP and despite the fact that my FT4 and FT3 weren't even half way up the range at that point, he lowered my dose because he wanted to normalise my TSH, which at that point was 0.02 (0.27-4.2). I knew what would happen, my FT4 and FT3 have subsequently dropped and my TSH hasn't budged. By the time he lowers my dose sufficiently to "normalise" my TSH I'll be half dead! So that's not happening!!! I understand that because I take a combo of T4 and T3 my TSH will be suppressed. Is it also the case that the it takes longer than 6 weeks for the TSH to normalise anyway??

At the moment I am horribly, horribly hypo and all over the place! I also think my thyroid is looking a bit enlarged (I have Hashimoto's so understand that this might happen). I can't feel any lumps it just looks generally bigger. I was called into the surgery at one point so that GP could feel my glands etc. but it may as well have been a telephone appointment as there was no way that GP was coming anywhere near me as we both sat at opposite ends of the room fully masked up.

I have finally managed to arrange a telephone appointment this coming Weds with my usual GP. She hasn't worried about my low TSH over the last several years as my FT3 and FT4 have always been very comfortably in range. I received a letter from the surgery to book an appointment obviously because the other chap is still intent on normalising my TSH, but when I speak to my usual GP on Weds I am going to suggest quite the opposite that I am not over-medicated but under-medicated.

Previously I took 75mcg T4 and just 10mcg T3 daily. I am tiny (very petite and light) and this relatively small dose was doing the trick for a number of years. However, for the last 5 months I have felt increasingly hypo. Because I have to DIO2 polymorphism (from both parents, hence limited conversion of T4-T3) I am wondering whether it is time to try something different. I am wondering whether to suggest staying on the 50mcg T4 (as suggested by the gp that wants to normalise my TSH) but increasing the T3 in 5mcg increments. So in the first instance that would be 50mcg T4 and 15 mcg T3 (taken in split dose) daily, and see if I start to notice a difference. And, would be interesting to see if this improves the RT3/T3 ratio to something a bit more optimal??

All other things - diet (strictly gluten/dairy free) paleo/autoimmune, crucial vitamin levels are better than they have ever been. Ferritin did drop but is on it's way back up with regular consumption of liver etc etc.

Sorry for the ramble, really struggling to order my thoughts. Had three goes at spelling"variety" earlier on in the post! That's not me.....

Feeling very much at the end of my tether and feeling very fragile emotionally. I really don't want to be referred to an endo as 1) I will probably have to wait fro this appointment and I want to start now trying to turn things around, and 2) I am afraid that an endo will probably take me straight off the T3 (I do get it on the NHS at the moment) and myself and my usual GP had been doing OK on our own for the last several years.

Still rambling....Any help gratefully received.

[Lalatoot]

But then if RT3 is blocking T3 at cellular level Rt3 cannot block t3 at a cellular level. It was once thought that they competed for the same cellular receptors but it is now known that rt3 has its own receptors and is converted into t2.

[MacG in reply to Lalatoot]

Thank you so much. I am still very much feeling my way with this....and SLOWLY...very SLOWLY at the moment.

[Lalatoot in reply to MacG]

MacG I have spent 2 years adjusting doses of levo and lio so I know how you are feeling. It is a case of trial and error. It is also very much a personal thing. Some folk can manage with low ft4 when on combo but others need it over halfway through the range. Ft3 on combo needs to be up into the top third of the range as a guide on combo.Because you take liothyronine t3 your TSH will be suppressed.

So you can only change 1 dose at a time, wait 8 weeks, get blood tests, see how you feel and then decide where to go from there

I have decided to stay on my current doses for a longer term now to see how things settle over time.

[MacG in reply to Lalatoot]

Many thanks once again. You would think that GPs would know that TSH will be suppressed if Lio is involved. Really their grasp is SO basic. Wonder if there are any papers out there or stats regarding suppressed TSH and Lio. Would be useful to have these to hand. Also for reassurance.

[shaws in reply to MacG]

Few GPs know anything about clinical symptoms of hypothyroidism, otherwise many on this forum would have been prescribed due to symptoms alone as our old-fashioned doctors did and we were given a trial of NDTs (natural dessicated thyroid hormones).

[MacG in reply to shaws]

Hi Shaws, you wonder when, IF this will ever change!

[helvella Administrator]

You might find a recent reply I made on another thread of some interest. There is a LOT of reading!

healthunlocked.com/thyroidu...

[MacG in reply to helvella]

Many, many thanks. I've got a free afternoon, so here goes....

[DippyDame]

zrtlab.com/blog/archive/rev...

Might be of interest!

[MacG in reply to DippyDame]

Many thanks for the link. Much appreciated.

[shaws]

This is an excerpt plus link re RT3.

The body sometimes converts T4 into rT3 instead. This rT3 has little biological activity and is considered an inactive compound [1].

Clinical Evidence

There is little clinical evidence to support the use of rT3 testing.

While it’s been shown that rT3 levels may become elevated due to a number of factors (such as stress, weight loss, and liver disease), there is no evidence to suggest that rT3 levels can cause any symptoms of thyroid disorder [4, 7].

There is also little evidence to support the idea of “rT3 dominance”. Studies do show that rT3 is able to bind to the same receptors that T3 does. However, T3 has a binding affinity that is 100x stronger than rT3 and the concentration of T3 in the body is much higher than rT3. This suggests that rT3 levels would have minimal effect on the binding potential of T3 [8, 4].

labs.selfdecode.com/blog/re...

[MacG in reply to shaws]

Many thanks for this Shaws. I was investigating the rT3 angle because on top of lockdown/Covid etc have coped with a couple of major stressors earlier this year and lost a lot of weight both of which I know can trigger rT3. And, of course, stress is no good whatsoever when managing a thyroid problem! Actually a small but not insignificant part is the ongoing stressor of dealing with uniformed GPs/feeling like you are going it alone (but thank goodness for this forum and Thyroid UK), wondering whether the T3 will be withdrawn (and I'm one of the lucky ones who gets it on the NHS!) worrying whether your GP will feel the need to refer you to an endo ...and so forth.

On a different note, I recently attended an endo appoint with my 85-yr old mum who is coming to regret having had radioactive iodine treatment about 18 months ago. She was perfectly stable on Carbimazole and had "va va voom"! Since then she's struggled dreadfully with swollen ankles ("I've had beautiful ankles all my life"), ongoing rashes that appear on her lower legs, the usual hypothyroid digestive issues and a series of UTIs that are currently proving impossible to sort out, fatigue, headaches, weight gain and the list goes on. All symptoms new in the last 18 months. Could be put down to ageing but methinks this is too much of coincidence. Anyway, I digress! At the recent appointment the endo said "So tell me how you've been". Mum reeled off weight gain, fatigue, constipation.... and "I just don't feel like myself". The endo came back with "but we're here to talk about your thyroid". UNBELIEVABLE!! After I had mentally wrestled him to the ground I politely intervened...

Don't know why I felt the need to tell you that....but it felt cathartic "outing" what we are up against.

Will certainly check out the link. Many thanks.

[shaws in reply to MacG]

You've just stated the phrase the Endo made and I think many of the 'experts' think the same way, i.e. give patient a tablet to 'keep them happy' but they don't really have any knowledge and expertise our 'old doctors' had of the dismal clinical symptoms that a person has daily.

Many experts seem to have no clue how miserable people's life can be when we swallow tablets that are supposed to ease symptoms - but spoils their way of living and we should not have 'more' symptoms when taking medication.

It used to be thought that choosing medicine was a vocation in that they could restore our health and relieve symptoms. but I think it is now a 'career' and I also have been at the brunt of a rude doctor who loves his very expensive car but who wouldn't refer me to a specialist to confirm I had a certain condition so - in a round-about-way I finally was diagnosed.

The comment the consultant made to your mother just shows how inept their knowledge is and ignore the 'extra' symptoms we can develop if not optimally medicated. The experts have no clue at all about symptoms.

[shaws]

The following is by Dr John Lowe who was also an Adviser to Thyroiduk.org.uk before his accidental death. He was a Scientist/Researcher/Doctor and expert in the use of T3.

Excerpt:

Q 4. How useful is a reverse T3 test in diagnosing HYPOTHYROIDISM?

I believe the test is of virtually no value in diagnosing hypothyroidism, if by hypothyroidism we mean a thyroid hormone deficiency. When the thyroid gland produces too little T4 and T3, less of these two hormones are available. The vast bulk of what the thyroid gland produces and releases into the blood is T4. With a lower-than-usual amount of T4 available, its likely that more of it will be converted to T3 rather than reverse T3. This presumably results from a need to keep the T3 high enough to maintain effective cell function. Also presumably, reverse T3 production from T4 will decrease to some degree. As a result, in moderate-to-severe hypothyroidism we might find low T4, low-to-mid-range T3, and a low reverse T3. However, as far as I know, no researchers have shown that this lab result pattern is useful for diagnosing hypothyroidism.

This pattern in hypothyroidism is only a conception based on principles. But in actual practice, Ive rarely seen this pattern in hypothyroid patients. I believe the reason is that when the TSH and thyroid hormone levels are in range, their levels vary (as Japanese researchers say) dramatically every thirty minutes or so. There is no correlation from thirty-minute period to thirty-minute period, day-to-day, and week-to-week.

drlowe.com/thyroidscience/c...

[MacG]

Hi Shaws, many thanks again! This makes sense! I will follow up the link.

As I am now looking at things having thought about what all of you wonderful people have passed on my way, it is simply that my dosage has not been sufficient and my levels have simply dropped too low, with a good dollop of stress mixed in there too. The GP who advised lowering the dose about six weeks ago said to have a blood test at the 3 week mark after lowering dose. I thought 3-weeks is too soon. More like six weeks? But he was very brusque and I felt too ill that day to question! In the event, I waited 4 weeks to the day after lowering my dose to test. At that stage my T4 was 13.2 (12-22), T3 was 3.52 (3.1-6.8). I am now a couple of weeks further on (in fact at the 6-week mark) so on the lowered dose my levels will have dropped even further and to use my mum's words "I don't feel at all like myself". Over the weekend I have put my dose back up to what I was on previously, I am not waiting until the GP appt Weds. On the previous dose my levels were: TSH 0.02 (0.27-4.2), T4 15.2 (12-22) T3 4.2 (3.1-6.8), which is perfectly acceptable perhaps even with a bit of wiggle room for an extra 5mcg T3 later in the day. I think I am very conservative/concerned because I don't want to over medicate and I always have my TFTs done first thing in the morning having not taken my daily dose yet that day, so I am thinking well the T3 is going to be somewhat higher about 3-4 hours after I have taken it, so tread carefully.

Sorry I'm rambling again...

[shaws in reply to MacG]

I take T3 only. I have the earliest available blood draw and take my dose after the blood test - not before. My every day dose I take when I awake with one glass of water and wait an hour before I eat. I feel fine and have no symptoms.