T3 and rT3 - Treated with Cytomel

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Is anyone else on Cytomel long term? I have had my numbers checked a couple of times. Currently my numbers are:

Free T4 - 1.26 ng/dl
Free T3 - 4.2 pg/dl
rT3 - 23.2 ng/dl

My dosage of Cytomel was just increase from 15mcg a day to 25mcg a day. My metabolism feels like had increase substantially and I my muscle often feel and look flat unless I increase my carbohydrate intake. Just wondering if anyone else was on Cytomel and how it effected them?

 

[Gman86]

Is anyone else on Cytomel long term? I have had my numbers checked a couple of times. Currently my numbers are:

Free T4 - 1.26 ng/dl
Free T3 - 4.2 pg/dl
rT3 - 23.2 ng/dl

My dosage of Cytomel was just increase from 15mcg a day to 25mcg a day. My metabolism feels like had increase substantially and I my muscle often feel and look flat unless I increase my carbohydrate intake. Just wondering if anyone else was on Cytomel and how it effected them?

How much NDT or T4 are you taking? Looks like you need to lower your dose of whichever one you’re on, so that RT3 comes down. You want that in the single digits ideally, but at least below 15

 

[Gman86]

Definitely be careful of raising free T3 too high. Free T3 at too high of levels starts to not only metabolize fat, but also metabolize muscle. Or at the very least make new muscle growth very difficult. Having a flat look to your muscles is extremely common with elevated free T3 levels.

 

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How much NDT or T4 are you taking? Looks like you need to lower your dose of whichever one you’re on, so that RT3 comes down. You want that in the single digits ideally, but at least below 15

I am not taking NDT or T4. I am strictly taking 15mcg of Cytomel (liothyronine sodium). My PA recommends of the Free T3 to rT3 ratio above 20%. Currently it is around 18%.

 

[Vtail]

Definitely be careful of raising free T3 too high. Free T3 at too high of levels starts to not only metabolize fat, but also metabolize muscle. Or at the very least make new muscle growth very difficult. Having a flat look to your muscles is extremely common with elevated free T3 levels.

What would be considered too high for Free T3? Anything above the lab range? Or some other number? And other than blood tests, are there any other symptoms or indicators that might tip off someone that they need to cut back on the T3 supplementation?

 

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Definitely be careful of raising free T3 too high. Free T3 at too high of levels starts to not only metabolize fat, but also metabolize muscle. Or at the very least make new muscle growth very difficult. Having a flat look to your muscles is extremely common with elevated free T3 levels.

This is exactly what I am experiencing. However, I noticed if I bump my carbohydrate intake up to around 250 or more a day, then I start to fill out more.

 

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What would be considered too high for Free T3? Anything above the lab range? Or some other number? And other than blood tests, are there any other symptoms or indicators that might tip off someone that they need to cut back on the T3 supplementation?

I was told to pay attention to my resting heart rate. If it seems like my heat is racing or I start to feel crappy then I should lower my Cytomel dosage back down.

 

[Gman86]

How long have you been on T3 only? I’ve never seen free T4 stay mid range like that while on T3 only. Usually it drops quite a bit. And your RT3 shouldn’t be this high on T3 only either. I’m assuming you haven’t been on it for that long, based on your labs.

 

[Gman86]

I would say around 3.7-5.0 should be fine. I’m surprised your muscles are feeling so flat at 4.2.

And just look at a list of hyperthyroid symptoms, and make sure your don’t have too many of them. Having a couple wouldn’t be too much a cause for concern, imo.

 

[Vtail]

I was told to pay attention to my resting heart rate. If it seems like my heat is racing or I start to feel crappy then I should lower my Cytomel dosage back down.

I got labs back last week and my Free T3 was over 7. T4 was right at the low end of the range and RT3 is single digits. I feel fine in all respects, but got a bit freaked out at the FT3 number. Resting heart rate was normal too. I am taking 40 mcg of T3 per day. Will see what the doc says tomorrow.

 

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How long have you been on T3 only? I’ve never seen free T4 stay mid range like that while on T3 only. Usually it drops quite a bit. And your RT3 shouldn’t be this high on T3 only either. I’m assuming you haven’t been on it for that long, based on your labs.

I have only been on the T3 for about 3 - 4 months. He anticipates once I bump up to 25mcg for 3 months or so, my rT3 will drop and my Free T4 will come down along with it.

 

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I would say around 3.7-5.0 should be fine. I’m surprised your muscles are feeling so flat at 4.2.

And just look at a list of hyperthyroid symptoms, and make sure your don’t have too many of them. Having a couple wouldn’t be too much a cause for concern, imo.

I think the majority of my flatness is due to my diet. I was only eating around 100 - 200g of CHO a day. I really feel like I need to be more at least 300g a day.

What I was eating:

Protein: 300g
CHO: 250g
Fat: 125g

I think I need to adjust this to:
Pro - 250g
CHO - 300g
Fat - 125g

Keep in mind I am currently 6'3 aprx 245lbs at around 18 - 20% bf.

 

[Gman86]

I have only been on the T3 for about 3 - 4 months. He anticipates once I bump up to 25mcg for 3 months or so, my rT3 will drop and my Free T4 will come down along with it.

oh wait, just checked the free T4 range, and you’re at the bottom of the range, so that actually makes sense. Still surprised your RT3 is so high. It will definitely go down now that you’re on 25mcg/ day. And Free T4 will drop a little as well. Just be careful not to get your free T3 up too high. I’m still surprised your muscles are starting to look flat already at 4.2. That’s obv not a good sign, especially considering your free T3 is most likely going to go up on the new dose.

 

[Gman86]

I think the majority of my flatness is due to my diet. I was only eating around 100 - 200g of CHO a day. I really feel like I need to be more at least 300g a day.

What I was eating:

Protein: 300g
CHO: 250g
Fat: 125g

I think I need to adjust this to:
Pro - 250g
CHO - 300g
Fat - 125g

Keep in mind I am currently 6'3 aprx 245lbs at around 18 - 20% bf.

Oh definitely! I’m 140lbs and I eat around 250 carbs most days. Sometimes I’m in the 300 range. You absolutely need more carbs. Probably around 400g, would be a good sweet spot. Maybe a little less on non-workout days, and maybe slightly more on workout/ high activity days. Your protein intake is pretty damn good. You can keep that between 200-250. Any higher isn’t necessary. And then just fill in the rest with healthy fats.

 

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oh wait, just checked the free T4 range, and you’re at the bottom of the range, so that actually makes sense. Still surprised your RT3 is so high. It will definitely go down now that you’re on 25mcg/ day. And Free T4 will drop a little as well. Just be careful not to get your free T3 up too high. I’m still surprised your muscles are starting to look flat already at 4.2. That’s obv not a good sign, especially considering your free T3 is most likely going to go up on the new dose.

Bottom of the free T4 range? My reference range says: .082-1.77 and my lab was 1.26

 

[Gman86]

Bottom of the free T4 range? My reference range says: .082-1.77 and my lab was 1.26

Oh you’re right! I was looking at the wrong range in my lab work. Ya, so that’s surprising that it’s still decent. But it will definitely drop closer to the bottom of the range soon. What was your free T3 before starting T3?

 

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Oh you’re right! I was looking at the wrong range in my lab work. Ya, so that’s surprising that it’s still decent. But it will definitely drop closer to the bottom of the range soon. What was your free T3 before starting T3?

Starting back in April was:

Free T4: 1.39
Free T3: 3.8

 

[Gman86]

See, this is interesting. I was under the impression that taking exogenous T3 will cut off the negative feedback loop, and cause natural production to stop. But what’s going on here is you still have natural production going on, and the 15mcg of T3 is just adding onto it. What’s your TSH, that will tell you how much natural production u still have going on.

 

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See, this is interesting. I was under the impression that taking exogenous T3 will cut off the negative feedback loop, and cause natural production to stop. But what’s going on here is you still have natural production going on, and the 15mcg of T3 is just adding onto it. What’s your TSH, that will tell you how much natural production u still have going on.

Starting TSH was 2.69

I haven't had my TSH checked since April. I will have it re-check in a couple months when I have my complete lab review.

 

[Gman86]

Starting TSH was 2.69

I haven't had my TSH checked since April. I will have it re-check in a couple months when I have my complete lab review.

Guarantee you still have a decent TSH, and have some natural production going on. That’s the only current logical explanation.