Looking for feedback on T3 and Blood sugar

I know I have seen some people in the past mention that T3 increased their insulin levels and blood sugar. Despite all the wonders of T3, some of us are well on T4 only. Can anyone who has experience with this please comment? I know of at least one person here on this board who gained weight when they added T3 or went T3 only. To me the only explanation is the insulin connection. 

To start with my ft4 was on the low end of the range and ft3 a little over the middle of the range. I wonder if I am one of those T4/NDT people. Currently am planning on T3 only and need to save myself from further worsening of my obese condition. 

12 Replies

  • Ah, this is a fun one. :) Increasing your body's supply of T3 does indeed increase blood sugar. But your body's supply would be increased even taking levo, so long as your body is good at converting T4 to T3. It's not uncommon for people to find they have pre-diabetes or full-blown diabetes after they've been on hormone replacement for a while. The metabolism works better - that is after all what thyroid hormones do. But if you're insulin resistant, that causes a problem, because the body can't handle the extra glucose. Which begs a question - was it that your body was being clever in down-regulating your thyroid because it knew you were insulin resistant? Bodies are cleverer things than we give them credit for - they compensate. Homeostasis. :)

    But I digress. Don't think I've seen many people gain weight on T3. Lose it, yes. But blood sugar inevitably rises when cells are working properly - as they do in the presence of sufficient thyroid hormone. Whether that causes a problem or not depends on how well your body handles the extra glucose.

  • Aah, I see. Now things are getting interesting. I know I am insulin resistant for a fact. My glucose tolerance test says so. Now this is a huge problem. How do I reduce my weight without increasing my metabolism?

  • Hmm. Well... :)

    Your metabolism needs to rise for you to lose weight. And losing weight reduces insulin resistance. It's one of those circular things. I'm not sure that anyone here has kept stats of what happened to their blood sugar as they introduced T3, whether they found it initially rose but then went down again as weight decreased. That would be my guess - but a guess only.

    Hopefully someone else will weigh in with something better than my guess. :)

  • Forgot to mention that I am getting a cortisol test done and that might reveal something blood sugar related. 

    Today I took my first dose of T3 ...split a 50mcg pill - had one at 7:30 am and the rest at 10am when I felt like the first dose was wearing out. I felt more alert after the first dose but progressively tired and had to nap at 11. I woke up freezing. What the heck is going on?

  • A bit surprised that I am the only one here with blood sugar problems.

  • I suspect I have too but have been told that H1AC(?) test was fine. Have put on masses of weight around the middle and crash sometimes after certain foods. Had a pudding whilst eating out.... Then crashed. the person I was with said they knew I complained of getting tired but couldn't believe it said it was like a switch had been turned off.

  • Hi , I too have blood sugar problems. I was diagnosed with T2 diabetes late 2008. I insisted I was not diabetic and that it was something else. To cut a long story short I actually had thyroid cancer, which was removed 3 years ago. I'd started on diabetes medication 6 months before I found out I had thyroid cancer and managed to get my blood sugars in the normal range. However, I needed t4 after thyroid surgery and 6 months later my blood sugar had gone up. I was very ill on t4 so endo put me on t4 and t3 combination. Blood sugars up again and some weight loss. I was still very ill so endo started me on Armour thyroid blood sugar slightly lower than t4/t3 combination but lost a stone in weight that had been gained on the synthetic medication. I self test my blood sugars and they're still high but I am much better on armour and hopefully will stay on this if cancer hospital will accept the cost and prescribe it.

    According to the patient leaflet on the armour thyroid it does say that it can affect blood sugars and diabetes medication may need to be adjusted. This is a price I have to pay to feel more human again. 

    TT xx. 

  • What do you take for your thyroid Lolajone? The crash sounds blood sugar related. You can get a Glucose Tolerance Test done which tells you a lot of things about your insulin sensitivity and blood sugar control. You can also just do a fasting insulin and post prandial with blood sugar if you can't do GTT

  • I'm on 125mg t4 and 20mcg t3. I've told endo about symptoms and crashes and just got fobbed off with the h1ac result being fine, I didn't feel I knew enough to argue. Will have to look into these tests. Thanks

  • Sure lolajone. If your gaining weight you also might do well from increasing t3. But do it cautiously due to the above mentioned blood sugar. I am a novice at this so I dont knw how the two affect each other 

  • I have wondered about my blood sugar/insulin for a while too. I literally need something sweet a day as I feel my body dip an I literally drain like a battery. But the sugar doesn't cause me to dip it actually helps me to get energy. I think I might get a glucose test as I know there are different types of diabetes. I've tried regulating it by eating more fruit and replacing sugar but that just makes it worse. When I cut out sugar completely I get really ill and just can't function. My body shuts down. 

  • I started T3 for the first time 3 months ago - and to my horror I gained 10 pounds and I already had a BMI of 40. I have PCOS and have been on Metformin (which suppresses my TSH and worsened my hypothyroid symptoms) for over 10 years, so I have a blood sugar monitor and could try to form a picture of what was happening when I ate. It seems the T3 raised my glucose levels and started a chain reaction of raised insulin and fat deposits overnight. I can gain 4 pounds in 24 hours if I eat a rice meal which is not particularly high fat, just high carb and therefore has a high glucose load. I am trying to manage this by spreading out my metformin tabs so I have 1 every 6 hours and this seems to keep my insulin levels down, but I am off to see the local Endo in a few weeks to ask for a better diabetes drug.

    Knowledge is the only way we can heal ourselves. We have to keep educating ourselves and taking responsibility for our own health. The NHS is there for when we become seriously ill with something life threatening, but for these pesky endocrine problems its hard to get any traction, especially when you are exhausted from trying to function at such a terrible disadvantage.

    I buy my NDT from USA and top it up with T3 that I buy from Europe. If the endocrinologist won't help me control my sugar levels with a decent drug I will have to buy that privately as well. Where will it all end?

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