Avatar universal

Why would my ft3 take a dive.?

I haven't checked in here for many months. To refresh, I was diagnosed with Graves in May of 2017 spent 10 days in hospital on cardiac ward finally had heart shocked to regain rhythm . I  had RAI the following week and went hypothyroid in August 2017 and started synthroid. I had a very hard time with horrid symptoms at each increase. I had to go very slowly.

I take synthroid each morning when waking with a full glass of water and don't eat or drink anything else for 3-4 hours. I withhold hormones till after blood work.

These are my last sets of labs... after 8 weeks averaging 140.71 ...( (5)137+ (2) 150) on Oct 2
TSH ...3.307. (.340-4.820)
Ft4 ...1.07.  (.60-1.20)
Ft3. 3.22.  (2-3.50)

I felt great there, lots of energy, great sleep and no heart symptoms.

He wanted to do just a little increase... (chasing TSH I think) so I went to an average of 144.42  ((4) 150+ (3) 137 )

The first 6 weeks on that dose was fine... I tested 11/09
TSH 2.0
Ft3.  3.08
Ft4.   1.19.

So I held there.... it's now been roughly 9.5 weeks..my energy level is great..... my sleep is rough....,I have short runs of tachycardia and a variety of pvc/pacs..which I hate...... so I decided to test this morning....
Ranges same as above...
Ft4. 1.12
Ft3  2.42

So my ft3 went from 3.22 to 2.42 which seems to be quite a drop...

My questions are.. can having  a high level of  ft4 stress my body and that stress cause my ft3 to tank?
If it were you would you cut back on the synthroid?
Or just hold and see if it settles out?

My vitamin D Is in range and very close to being optimal.. I take 2000 ius a day. My iron is good though I don't recall the number, it's not just in range but in the upper half of range..my selenium likewise is upper 25%of range......I'm not interested in adding t3 .. I'm just curious if this is common for numbers to swing? And do you think this is the cause of the return  symptoms? I haven't changed anything other than have put in quite a few long days...
Thanks for your input
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1756321 tn?1547095325
Tired Thyroid has an interesting article - Why You Should Wait 6 Weeks Between Dose Changes. Here is an excerpt...

"T4, T3, and rT3 know and interact with each other, since they all work at the same factory.  They constantly check in with each other to determine if they should increase or decrease their own production, based on the others’ levels.  When T4 is high, the enzyme that’s responsible for T4 to T3 starts to slack off, and less T3 is made.  This prevents a person from becoming hyperthyroid. It also explains why patients don’t usually see improvement when prescribed more and more T4."
Helpful - 0
Thanks, I went and found the article and read it... Do you think the lower ft3 would cause symptoms?.
You sound hypo from your symptoms. Try going back to the dosage you felt good at.
Thank you Red-star, the article and everything working together and needing to be in balance makes perfect sense to me. That would likewise explain why my ft3 was high and then plunged..
Avatar universal
Sedge - you have been on quite a journey with your thyroid!
To answer your question, "Why would my ft3 take a dive?", the short answer is that your body only wants FT3 around 2.4!  I believe that you are now taking a bit too much T4.

I will explain more tomorrow night, right now it is past my bedtime...
Helpful - 0
I am anxiously awaiting your answer. Thanks in advance.
Avatar universal
Just thought I would add.. whatever is happening with my body continues.. my hands are swollen, every  joint in my body hurts... I can honestly say I have never before had pain in my hips...it is actually painful to touch my elbows, knees etc

When my TSH hit around 8 (this was about a year after being hypo, it started around 66) I gained 12 pounds...over the last 3 months or so it slowly went away. Over the last 3 days my weight has increased 8 pounds, I'm sure most of it from swelling...

Any thoughts?
Helpful - 0
Avatar universal
Just posting here to bring this back to top...hoping for some input... I guess with no direction I will cut the synthroid and see what happens..
Thanks again for all the past advice
Helpful - 0
649848 tn?1534633700
Hi Sedgly... It's been a while.  I'm sorry to hear you're having difficulty again.

Free T4 is converted to either Free T3 or Reverse T3... you may be converting more to rT3 than Free T3.  rT3 is inert and prevents Free T3 from entering the cells.  If you can test again and get rT3 tested that would be good, but it needs to be tested at the same time as Free T3, because it's not just a straight result; it's a calculated FT3:rT3 ratio that must come from the same blood draw.  

There may also be another factor preventing adequate conversion of Free T4 to Free T3.  You say your Vitamin D and iron are "in range" - upper parts; perhaps there's something preventing your body from utilizing them properly.

The pain can be caused by low Free T3 levels because that's the hormone that's actually used by individual cells in your body (Free T4 is the storage hormone that must be converted to Free T3 and TSH is merely an indicator that neither causes nor alleviates symptoms)... There could also be other factors involved in the pain issue, including stress.

The weight could also be lack of Free T3, since, again, that's the hormone the individual cells need.  Since you've been under stress, that could also be adrenal/cortisol related.
Helpful - 0
Hi, Barb, it has been a long time. Thanks so much for your input. I know I will eventually get this figured out.
Avatar universal
Sedge - sorry for the delay, but I have been dealing with a bout of the flu.

Even though you have increased your synthroid (T4) 44%, from 100 t0 144, your body is regulating your fT3 to a narrow range around 2.3 to 2.4 ng/dL. However we don't know if that was your natural level prior to RAI, and we don't know if that level will eliminate your hypo symptoms. [Note: at this point some doctors would look at your fT3 level and say you are a 'poor converter' of T4 to T3. Don't believe that - it is simply not true.]

You have two things happening that are different from other people taking T4. Of the thyroid labs, TSH takes the longest to change as you change your amount of T4, but your TSH came down a lot slower than usual. I don't know why that happened, but TSH seems to be close to the expected range now. But your TSH should definitely not be used to decide if your T4 dose is appropriate. Second, your ratio of fT3 to fT4 is high. Natural fT3/fT4 ratio is higher than fT3/fT4 ratio for T4 users, but your fT3/fT4 ratio was even higher than natural. From this I conclude that you were having lingering effects from your Graves disease. This effect is diminishing but you should discuss this with your doctor and possibly consult with your endo.

You have described a pattern of being relatively symptom free for 1-3 weeks after you increase your T4, then symptoms return by 4 weeks. I think this can be explained as follows. Your RAI treatment did not totally kill your thyroid gland, so it is still capable of producing some thyroid hormone. Each time you start a higher T4 dose you get that T4 plus a certain amount from your thyroid gland. After 4 weeks on a given dose of T4, your TSH is a bit lower so you get less T4 from your thyroid gland. The result is that your fT4 and fT3 slowly decrease due to decreasing TSH after a dose increase. You can see this effect in your labs - on 100 T4 your fT4 after 4 weeks was 1.0 but it tapered off to .8 and .84 in subsequent tests. It appears that the surge in hormones that you get when you increase your dose is enough to control your symptoms, but the subsequent decrease in hormones results in return of symptoms. It has been a roller coaster for you, but I think it should be heartening for you to know that there may be a level that will control your symptoms - we just have to figure out what it is and how to maintain it.

Turning now to your most recent doses at 141 and 144 mcg T4. I think here that you have crossed the line into too much T4. Let's do some math: if you take 125 mcg T4 and have 80% absorption, then you are getting 100 mcg T4. Or taking 140 mcg T4 at 80% gives you 112 mcg. But a normal functioning thyroid produces 90 to 100 mcg T4 in a day. Now these numbers are not exact, but pure common sense tells you that somewhere in the 125 to 150 mcg T4 range you are taking more T4 than what a normal person gets from their thyroid. Another clue is that your fT4 readings of 1.07 to 1.19 are above 0.9 the midpoint of the reference range - above the mid-point means above normal.

Why is it a problem to take too much T4? The T4 that you take does not pile up in your body; your body reaches an equilibrium so that every day it eliminates the T4 that you take each day. It normally eliminates T4 by converting it to T3 and Reverse T3 (rT3) in roughly equal amounts. Now on 144 mcg T4 your ft3 is 2.42, which is hardly higher than before. Even though you are taking a lot more T4, your fT3 is about the same - this means that most of the additional T4 that you are taking is being converted to rT3. This is your body's way of preventing you from becoming hyperthyroid, because rT3 is not an active hormone. But even though it is not active, an elevated level of rT3 is not desirable because you have inactive rT3 in parts of your body where you would normally have active T3 - the end result is that your get hypothyroid symptoms. Indeed a paradox - hypo symptoms from taking too much T4!

OK. What to do? I would cut back a bit. Hopefully you have kept a daily diary, review your notes to see when you had the longest period without symptoms. 125 mcg T4 is a very common dose and personally I believe that should be the maximum.

This is very important - you should very carefully review your notes on 141 and 144 T4. You had 8 weeks on 141 T4 and 6 weeks on 144 T4 where your fT3 was 3.22 and 3.08, and you did not mention a lot of symptoms. If you were virtually symptom free in these periods, then that gives you a fT3 target to shoot for.

If it does turn out that your fT3 target should be around 3.0, I don't think you will get there with only Synthroid. You will have to add T3 to get there. I see where you mentioned that you are not interested in T3. Perhaps you could explain where you are coming from on that.

That's it for now. I hope that you can follow all this.
Helpful - 0
Thanks so much for your informative explanation.

First, before i forget, I'm sorry to hear you have had the flu and hope you are recovered from it soon.

So I do have a few questions if you don't mind.
Why would my body regulate my t3 to be low after it being high for so long? Would stress alone cause this? Or the t4 intake being too high?
So, is the consensus to totally ignore the TSH?  When I googled optimal thyroid levels it listed both ftp in the upper quarter and ft4 in the upper half...where do you think they should be?  
Truth is I really don't care where the numbers are as long as I can level out.
If TSH is not used to decide appropriate level of t4 what is?

I know nothing about ratios so I cannot comment on those.

I'm not sure I agree with the theory you set forth on why I have hellish symptoms 4 weeks after each increase (though I need to spend some time thinking on it before I disagree). The reason I'm not confident in that explanation is because after a week or week and a few w days of hellish symptoms I would be fine...until 4 weeks after the next increase...

I have more I would like to ask but I'm on my phone while  waiting for  arrivals and I don't have the time right now..

I felt the best at 140....but was told my Tsh was too high...

As to the T3 , I will explain where I'm coming from when I return.
Thanks so very much. I truly appreciate this.
Avatar universal
I just wanted to point out that there are numerous studies that show that patients taking T4 meds with their dosage being titrated by TSH level,  typically end up with inadequate FT4 levels and FT3 levels that are even lower in their ranges than would be expected based on their FT4 level.    In addition there was a recent, excellent study of thyroidectomized cancer patients in which the relationship between FT3 and the incidence of hypo symptoms was quantified for the first time.  The authors concluded that, "Hypothyroid symptom relief was associated with both a T4 dose giving TSH-suppression below the lower reference limit and FT3 elevated further into the upper half of its reference range. "  

The member's posted test results are far from those levels, and T4 dosage could be reduced along with adding a source of T3 to meds, titrated as needed to relieve hypo symptoms, since the needs of everyone can be somewhat different.  The correct definition of hypothyroidism is not just "inadequate thyroid hormone", but instead it is  "insufficient T3 effect in tissue throughout the body, due to inadequate supply of, or response to, thyroid hormone".   I  see no indication that the member will reach adequate TISSUE T3 EFFECT without the addition of a source of T3 to meds.
Helpful - 0
Thanks Gimel for your input. You may recall how terrified I was to start the synthroid.....

I may end up on t3 also... time will tell...    

It just really surprised me that it changed...
Avatar universal
Hi Sedgly,
message rec'd and I'll respond.
Helpful - 0
Avatar universal
Hi Sedgly,

Regarding TSH: No, we should not ignore TSH, but we should not use it as the sole guide for adjusting T4 medication. Endocrinologists (in the past) have assumed that if TSH is within the reference range then all other thyroid markers (like fT4, fT4, etc) will be within natural range and that a person will not be hypo- or hyper- thyroid. Consequently their guidelines for treatment are based on that assumption, those guidelines are widely followed by endocrinologists and doctors who are not up-to-date on research, and it is plastered all over the internet. However, thyroid suffers have known for a long time that this assumption is false and, as Gimel has pointed out, thyroid researchers have recently (2017, 2018) shown this assumption to be false.

That TSH should not used it as the sole guide for adjusting T4 medication applies even more so in your case, because your TSH was so slow in coming down. The movement of your TSH was occurring much slower than the movement of your fT3 and fT4, so any adjustments of your T4 intake based on TSH were totally inappropriate.

If TSH is not used to decide appropriate level of t4, then what is?  Again, the paper that Gimel referred to advocates an emphasis on treating your symptoms, and states, "optimum therapy may be best approached by maintaining adequate FT3 levels and, if required for symptom relief, elevating FT3 above the median, but still remaining within the reference range." They go on to say, "...all three parameters TSH, FT4 and FT3 and their interrelations should be considered for dose adequacy."

Re the cycling of your symptoms. I have reviewed your posts again. My impression now is that you are relatively symptom free for several weeks after each increase of T4, symptoms return at about 4 weeks lasting for about a week, and then you have alternating periods of symptoms and no symptoms. I think my explanation could still be valid. Each time you start a higher T4 dose you get that T4 plus a certain amount from your thyroid gland. During the first 4 weeks on that dose your TSH slowly decreases so T4 from your thyroid gland also slowly decreases and in turn your fT4 and fT3 slowly decreases. The initial fT3 after the Synthroid increase seems to be enough to control symptoms, but the lower amounts are not.

But how to explain the subsequent alternating bouts of symptoms. I believe that what you describe as anxiety, palpitations and tachycardia could quite possibly be atrial fibrilation (afib). I suffer from afib myself - paroxysmal atrial fibrillation - meaning it is intermittent and episodes do not last for more than seven days. There is no rhyme nor reason for the start of episodes, they can start any time night or day. Resting heart rate on my sports watch can be 80-90s as you describe, and easily go to 140-160 with exercise. I have worked to get my thyroid labs in the best place with a T4/T3 combination and I have eliminated hypo symptoms for the most part, but I still get afib.

So I am thinking it may be possible that your hypo symptoms are occurring at the same time as afib. It would be easy to find out. Whenever you have symptoms put on your fitbit. I think you probably know what your BPM is when your are feeling normal. If your BPM is higher than normal it may be Afib.

Now turning to what happened in your first weeks on 141 and 144 T4. I have seen it before where people get higher fT3 labs (like your 3.22 and 3.08) at T4 levels of 137-150 mcg and then fT3 goes down. It is my hypothesis that it takes a certain amount of time for your body to recognize and react to highish fT3 and then it takes steps to prevent you from becoming hyperthyroid. But like I said before, you should review your notes to see if you had any symptoms when your ft3 was up in the 3.08 - 3.22 range. If you did not, that would be very good news because you could target getting your fT3 up there. But like I told you last time, it would likely take a T4/T3 combination to do that. It's nothing to be scared of, lots of people are doing it now.

Even though you felt best at 140 mcg T4, if you go back to 140 your ft3 would probably not go back to the 3.22 range but would remain in the more recent 2.4 range.

I'll leave it a that for now, you have lots to chew on. Feel free to ask more questions if you wish.
Helpful - 0
Yes, I have found all sorts of stuff "plastered all over the internet" when it comes to thyroid treatment.. I'm trying hard to sort out what is right for me.

I stumbled upon a book recently , "Healing Hashimoto's: A Savvy Patient's Guide: Dr. Alan Christianson" which was free online and although I don't have hashimoto's it actually covers a bit of what I have gone through including the delay in TSH lowering and the  over raising of T4 ultimately causing the lowered FT3.

Don't think its afib causing the symptoms at the 4 week mark.. 1st because I spent  days in hospital with afib with RVR and I know what it feels like.. ( the only time I have had afib is when I first went hyper) and 2nd because at four weeks in the beginning not knowing it was something that would pass I would go scurrying to my doctor or ER and never was it afib.. it was sinus tachycardia with lots of pvc/pacs… along with a variety of other things..  its the visits that made me realize it was happening every time at the 4 week mark... at each of those times no matter if my TSH was in 50s or single digits.. my ft4 would be high or off the charts.. it would then settle after a week or so..  I no longer care about the 4 week mark,, its something I accept as something that just happens for what ever reason.. I know it will always pass..
The cortisol/adrenaline/ whatever they were rushes that would come and slam my heart rate up and then back down have also left months ago..

I cut the doseage of T4 just a few weeks ago and I do feel better.. my heart rate is almost stabilized..  surprisingly the thing that has come is  being totally fatigued after just a short work out.. if I could hold the good days I would be good to go..the hassle is I can have an entire week or two of great days then symptoms return.. it appears when I feel pretty good my ft3 is up and when I feel crappy it is down.. it fluctuates apparently quite a bit.. to date I have found no reasoning for it.. the book I mentioned above goes into many things that could cause that but unless I have some hidden disease that I don't know about it shouldn't be happening.. is this common? and does it eventually settle out?


Avatar universal
just thought I'd pop in and let y'all know how the lowering of  synthroid went.. it's been right at 7 weeks.  Had labs Thursday
Tsh.  3.81    (.34-4.82)
Ft4.    1.02.   (.60-1.20)
Ft3.   3.12.   (2.00-3.50)

So my ft3 returned from the  2.42 it was to 3.12.
It was a hellish 7 days and frankly I wasn't sure I would survive it.

In the midst of it all I had labs for other stuff  done and my numbers look great, only one I still need to do is vitamin d..

I feel great but know I'm not stable.. I am hoping this is finally the correct dose. So my question is, how long after hitting the right dosage does it usually take for everything to settle...

And do the thyroid numbers look ok? From a number standpoint? As I said, I feel great....I know my tsh always lags after my ft3 increases, at least it has every time in the past, so I expect it will drop in the next 2-3 weeks...
Helpful - 0
I'm glad to hear you're feeling well again.

I'm not sure what you mean by how long it takes for everything to "settle"... if you mean how long it will take for symptoms to abate, that will depend on what symptoms you have.  The body will, typically, take care of the most important things first, such as heart, temperature, etc, then worry about things such as hair loss or weight.

As far as the numbers go, your FT4 is higher than it needs to be at 70%, but your FT3 is about where it should be at 75%.  As long as you feel good, you're probably okay, but remember, FT3 is the active hormone,  it could tip to the hyper side quickly, if more FT4 starts converting to FT3.  With FT4 as high as it is a flip over could go pretty quickly, but you know the signs of being hyper so be ready to go get blood work.
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