Thyroid Disorders Community
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Avatar universal

Why is FT4 so low, yet FT3 so high?

I am presently taking thyroid medication of T4 80/T3 15, taking it 1/4 at dinner and the rest at bedtime. I do take selenium to help with T4 to T3 conversion. My question is, my TSH is suppressed and my FT4 well below the normal range and yet FT3 is high above the normal range...how could this be? Am I am superconverter? I take 200 of selenium daily and prior to starting selenium my FT3 was low normal. Any ideas?
11 Responses
1841872 tn?1324669689

I had a similar experience. My T4 was low and not moving but my T3's were getting higher.

A few questions.....

What are your Free T4 &3 levels and lab ranges (can you post them?)

What type of thyroid medication are you on?

Have you had your Selenium levels checked before starting your supplements?

How long have you been on the dose you stated?

What happened to me was ...my T4 medication was not working so I switched bands along with going higher in the mcgs. Also I needed to cut down on the added T3 medication.

I am still in the "finding the right level"...but feeling good right now.

649848 tn?1534637300
Please post your actual test results, with reference ranges so we can take a look at them.

You might want to think about having RT3 tested to see if too much FT4 is being converted to RT3, so the FT3 is circulating in the blood, but not reaching the cells.
Avatar universal
How are you feeling at those levels?
Avatar universal
Also you mention taking the medication "at dinner" and the rest before bed time.

Medication should be separated by food as it affects absorption.  Could it be possible that because some of it is taken with food, the T4 is not being absorbed but the T3 medication is?

Many people state they have trouble sleeping when taking T3 medication close to bedtime. Do you have trouble sleeping?

The most common way to take thyroid meds is one dose (or the only dose for many people) in the morning. If a end dose is taken it is usually early to mid morning.

Everyone is different and you need what works for you.  So you may want to consider switching to taking the 1st dose of the day early when you first wake up.  Do not eat for about an hour or so afterwards. Then take the 2nd dose about 2 to 4 PM.  Many people will take 100% of the T4 medication in the morning and half of any T3 in the afternoon.
Avatar universal
Well, here are my labs:
TSH   0.007    (0.270-4.20)
FT4    0.75      (0.93-1.70)
FT3    4.52      (2.10-4.40)
RT3    238      (90-350)
Thyroglobulin            177  (<40)
Thyroid Peroxidase   59   (<34)
I am taking a troche that is sublingual due to GI issues and I take
T4 80/T3 15.  I feel much better now than when I was on Armour at 2 grains and both my FT3 and FT4 were low then.

I do not have any trouble sleeping....if anything I am tired when I wake up.

I never had my selenium levels checked, just going to a nurse practitioner who suggesting taking 200 of Selenium daily, which I do.

I figured since it is sublingual meds, it did not really matter as much with the food schedule. I just cannot get why taking 80 of T4 my levels do not hit low end and only 15 of T3 I was way over the top?

The NP wants me to cut back on the dose some due to TSH being so suppressed and I have tried but feel worse....so I am trying to play with the dose to see how I feel best.

I was taking the meds in the morning, but they are made with cocoa butter and it seemed to make me have sinus pressure issues, so I went to taking it at night and then I do not notice it since I am asleep.

Any ideas of what to try?

Avatar universal
What are your symptoms?

Sometimes we have to just accept the numbers at where they are at as long as you feel well.

With the FT3 at 105% of the range I'm a bit surprised that you don't have Hyper symptoms.

If you feel well I'd not change a darn thing.  Don't try to fix what isn't broken.

On the other hand lowering your T3 med and raising your T4 med may make some sense if you really want to change something.
Avatar universal
Well, I feel overall pretty good...slight hyper symptoms with waking up hot and a little shaky in the morning. My memory is still awful and for some reason my vision is worse, unless that is just coincidence? I finally have been able to lose weight though after struggling for so long.

I have to guide my NP as she wanted to lower both T4 and T3 and wants me to follow this protocol by Dr. Alexander Haskell, but according to that protocol, you need antibodies normal....I have never had that!

Thanks for you advice! I might try a little more T4, less T3, just afraid it will increase my RT3 then....such a puzzle!
1841872 tn?1324669689
I am going though the very same thing!

I lowered my T4 and T3 meds and at 2 weeks now starting to feel a little Hypo

waiting...for time to travel... again... for the blood test to see what direction to take....I will only have about 1 or 2 options left in measurement dose of the T4 and T3 together.

To me it looked like your T4 was low and your T3 too high....

I too am still trying to find the balance here as well...so good luck to us both!!
Avatar universal
Had you taken your meds before the blood draw?

"I just cannot get why taking 80 of T4 my levels do not hit low end and only 15 of T3 I was way over the top?"  

Only about 5% of the T3 in our bodies comes from our thyroids.  The other 95% comes from conversion.  People who have a "conversion problem" are really "slow" converters.  They still convert, just can't keep up.  

15 mcg of T3 is a fairly high dose.  Lots of our members only take 5-10 mcg per day if they're slow converters.

My suggestion would be to ask your doctor about going to 10 mcg T3 and 100 mcg T4.  The 5 mcg decrease in T3 is roughly equivalent to the 20 mcg increase in T4 since T3 is four times more potent than T4.
Avatar universal
Since I take my meds at night, I took them at 9 p.m. and then went the next afternoon, around 3 p.m. for the blood draw, thinking that would be enough time for the T3 to leave my system.

I am guessing the selenium and night time dosing is increasing my conversion rate since on 2 grains of Armour, which is about 76/18, my FT3 and FT4 were both low, yet TSH suppressed. I guess I could try to altered when I take the dose and see if this makes me convert less?

I think perhaps I should try the T4 100 and T3 at 10 and see if that helps to increase the T4 without lowering the T3 too much...I just do not want to increase my RT3 any higher than it is now.

649848 tn?1534637300
Make sure you remember, and remind your NP, that in a case like this, TSH is totally  useless, because it's not reflecting what's really going on.  
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