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T3 Only - Best way to dose, increase dosage?

Hey all, I won't go too much into my background of problems but I had some sort of subclinical hypothyroidism with TSH above 3.5 and T3 at the very bottom of the range. My doc prescribed me with T3 recently and it's changed my life, I felt like a new person (for a while!). Pretty much all my symptoms have improved, but I am still having trouble finding the right dose.

My doc seems to think I have some sort of thyroid hormone resistance, as I am able to take quite large doses of T3 over a day (I've taken up to 100mcg a day) and not get ANY hyper symptoms whatsoever. Right now I am taking 60mcg morning, 20mcg afternoon, and 20mcg night.

This seems to be okay, but I have read (dr lowe) that it is better to dose once daily to saturate the cells. Problem is when I started taking 60mcg all at once, I had a mild headache that lasted for an hour or so every time I dosed. This is normal from what I have read, and went away in a couple weeks, but I've tried 80 all at once and that same headache comes back. It's not bad by any means, doesn't last long... just annoying.

Anyway with all the T3 I am taking, my levels came back at 7.8 (3.2-6.4) pmol/L. Hence the suspected thyroid hormone resistance. My average resting heart rate is 68bpm, my morning temps come in at around 97.1f (96.4 per-medication) and my afternoon temps come in at 98.1f and the highest I've seen is 98.2f (pre-medication I never even hit 98f). So by any means I am not hyper.

Anyone got more experience with T3 only that might help me get to optimal dosing and schedule? I feel like I could tolerate more T3, perhaps at once but I just want to see what everyone else does. My doctor is good as he is helping me through this, but he says what I am doing goes against convention so is a bit worried.


7 Replies


Did you take T3 prior to your blood draw?


Hey clutter,

I took T3 about 14 hours prior to my blood draw. If I recall correctly I took 80mcg that day.



Okay, 14 hours gap means you are mildly biochemically overmedicated.

I really don't think it necessary to take T3 in one dose. It may have suited Dr. Lowe but it will cause issues for some people. Dividing dose eases the peak T3 spikes which raise heart rate. These peaks can cause heart arrythmias so it may be safer to divide the dose and spread the peaks.

You could simply increase T3 dose in 10mcg increments every 4 weeks until symptoms resolve but be aware that the risks of developing atrial fibrillation and osteoporosis do increase when FT3 is over range for a long period.

If you haven't done so already, ask your GP to check ferritin, vitamin D, B12 and folate because low/deficient levels are common in hypothyroid patients and can cause fatigue, musculoskeletal pain, low mood etc. similar to hypothyroid symptoms.


Yeah, that’s why my doc was a little freaked out and suggested thyroid hormone resistance. The thing is, I don’t feel any hypersymptoms at all, in fact when I drop my dose back (doc was worried) I start to feel hypo again. We can see the levels of free T3 in the blood, but we cannot see how well the T3 is working at the cellular level. That is something that would be interesting.

I don’t notice too much difference between dividing the doses and splitting them, definitely not in my heart rate. The only thing I notice is a mild headache when I take it all at once. Do you know what that is?

I started another thread but my ferritin was low, and the only time I’ve been able to get it to come up is while I’ve been on T3. It’s at an all time high of 58 since 11 years ago lol. I’ve taken too much iron supps but that’s a seperate issue.

I think I’ll kick in with 100mcg in 3 doses for a while and see how I go. I dropped it down to 40-60 the past week at my doctors request so I felt a little hypo.

Do you take T3, and if so, how much and when?

Do you measure your temps? My temps came up and then down as I reduced the dose (as one would expect). I’m still not warm, but at least my hands and feet aren’t ice anymore.



I don't know why you get a headache taking T3 in one dose but it's probably best to listen to your body and avoid headache by dividing dose.

I don't believe there is a cellular test. There is a tertiary centre at Addenbrooke's where secondary care endocrinologists can get advice about resistance to thyroid hormone from research specialists but first you'd have to run the gamut of secondary care endos who would almost certainly muck you up by taking you off Liothyronine or reducing dose until life was intolerable. When you don't fit the usual population range responses it can be better to trial your own doses IMO.

I was originally prescribed 60mcg in 3 x 20mcg doses. Then switched to Levothyroxine after RAI and felt poisoned. I've been taking Levothyroxine + T3 for 3.5 years, currently taking 75mcg Levothyroxine with 30mcg T3. I'm supposed to take 20mcg T3 am and 10mcg pm but take it all at once in the morning.

I don't measure temps. I have no thyroid so I don't need low temp to tell me I'm hypothyroid and I'm not titrating dose so any spike in temperature will be due to a fever. It took more than a year after I was optimally dosed before I stopped feeling cold to the core and another year before I began to sweat again when weather was very hot or under the duvet. I'm finally comfortable without socks between April - Oct but my hands are always cold.


Don’t experience headaches from T3 all at once anymore. It went away. Took 80mcg at once in the morning, feeling really good. This feels close to my optimal dose, but will see later today if I start crashing.

I think Dr Lowe really was into something when he said taking T3 at once is more effective at flooding the cells than multi doses.


Where to get Dr Lowes book about t3? any ideas ?


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