Low temp, but on high doses of T3?: Hi All I was... - Thyroid UK

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Low temp, but on high doses of T3?


Hi All

I was recommended to buy a fertility basal thermometer to take my temp for vitals while taking T3.

The digital oral basal thermometer is showing that my temp is not getting up to 37c even 2 hours after taking T3. I have just taken my temp a little while after I got up this morning and it was 35.3c. Last night 2 hours after taking 50mg of T3, my temp was 36.7c.

I have been on T3 only for some years and have generally felt very well, and warm (for the first time in my life! My husband has been with me since I was 15 yrs old and says that he never felt me have warm hands until I took T3, and I am now 53).

I don't feel cold and had thought that along with my now normal HR and BP I also had a normal temperature (I have been told that a fever thermometer would not accurately take low temps, so bought a new one as described....)

Why would my temp still be so low?


12 Replies

I am not medically qualified but our body temp varies throughout the day.

The fact that you feel 'warm' is the best way to judge if your dose is optimal.

Your numbers are also 'average' which is good.


Normal body temperature varies by person, age, activity, and time of day. The average normal body temperature is generally accepted as 98.6°F (37°C). Some studies have shown that the "normal" body temperature can have a wide range, from 97°F (36.1°C) to 99°F (37.2°C).

A temperature over 100.4°F (38°C) most often means you have a fever caused by an infection or illness.

Body temperature normally changes throughout the day.


Although we can feel cold when hypothyroid body temperature is a very poor marker for thyroid status. It can vary between individuals and is subject to influence by many factors. You are feeling very well, you should not let your body temperature overrule this.

Baobabs in reply to jimh111

I'm sure you are right! My temp rarely reaches 36 degrees ever, despite the time of day. I have never suffered the symptom of feeling cold with Hashi's and I actually always feel warm/hot regardless of the weather. ' Feeling well' has to be rated as an important sign of well being.

Baobabs in reply to jimh111

I also meant to say Endos don't seem to rate temperature as a significant symptom but that's no surprise.



37C is an average.

What I have read agrees with Shaws.

Adults. Among adults, the average body temperature ranges from 97°F (36.1°C) to 99°F (37.2°C).

Adults over age 65. In older adults, the average body temperature is lower than 98.6°F (36.2°C).

Thanks all!

I have been trying to follow Paul Robinson's book regarding T3 only, but got it after I had started being T3 only. I gave the book to my Endo even though she discharged me at the same appointment, so need to get another copy.

In writing this post, all the other posts about T3 and temperature came up, so I agree with all of you and the previous answers to the other couple of posts, that it isn't really important as long as you feel well.

I have been on 150 over the past few years, with good HR and BP and as I said temp seemed normal, until I got this new more accurate thermometer. I have low cortisol, although the endo just said that it was low but they wouldn't be doing anything about it as my SST showed that I was not PAI or Addison's. I may go for a ACHT test in 6 months to check for secondary and then try and find an Endo privately who specialises in thyroid and SAI (if such a one exists!) as I have been having a lot of problems with pain in my legs and fatigue again.

I have arthritis and recently had a steroid injection in my hip, which has helped the pain there tremendously and I can now walk more, but the heavy pain in my legs has persisted. I lowered my T3 down to 50 after the injection (I had previously lowered it to 75 because everyone on all forums seemed to think that 150 was too high and I had a blood test where my T3 was a bit over, although no hyper symptoms). Too many symptoms started coming back at 50mg so I am going back up again.

I wish I could find a good endo in the Oxfordshire area!

Thanks for you help all.

Hidden in reply to PiggySue

With the greatest respect, I cannot agree with some of the assertions made in some books and web sites. When I queried the matter of temp being a reliable indicator, one such ‘expert’ banned me from his FB group 🙄

We all know that we respond as individuals to medications and serum levels.

Unfortunately there are a few self styled experts out there whose arrogance is exceeded only by their lack of medical knowledge.

Wish I could find a good Endo ................ Period.

DippyDame in reply to Baobabs

Maybe give up the search and self medicate....you will get all the guidance you need from the experts here but you must be prepared to very carefully follow the advice given, read a great deal, learn about your condition, gain a thorough understanding of thyroid function, understand the importance of various nutrients, have tests done privately, have determination and lots of patience....and so on. It's a tough call.....but so is battling with medics who haven't got a clue!

Until - hopefully - the day comes when medics actually understand thyroid function (I suspect I'll be long gone by that time) then taking control of your own recovery is another option. Clearly it's not everone's preferred option but some of us do just that...with positive results.

Knowledge is power!

Baobabs in reply to DippyDame

You know I'm evolving into self medication with excellent help from folk on this forum. My friends, family and colleagues think it's disgusting and make me feel irresponsible and like a drug addict. I'm onto my 6th Endo in two different countries in almost 2 yrs and I'm certain they have no grey matter between them. They appear to never have asked where, why, what, where, when questions and to me have no interest whatsoever in their profession or more to the point Jo Average ( me). My so called friends, relatives and colleagues have no idea. If I'm vertical, smiling, positive and never rushed to hospital .............................. What on earth could be the problem !!!!!!!!!! I will fight to the end until I find and recognise me again.

DippyDame in reply to Baobabs

As I said, it's a tough call, thank goodness for the people here who understand...one of my relatives said recently, "Don't tell me I just don't want to know". Funny though, if they have a cold all sympathy is expected! Huh!

The neglect thyroid patients experience if they fail to respond to "this little pill (i.e. levo) is all you need to feel better" - said to me decades a go! - is nothing less than scandalous. It did nothing to help me. I cannot think of any other medical condition that is so badly treated and brushed aside as being some "bucket diagnosis" like depression, chronic fatigue etc.

Keep fighting for your health, we're all behind you. One day we'll be proved , and acknowledged, to be right! Until then we need to march to the beat of our own drum!

Take care

DD.....ranting again!

Baobabs in reply to DippyDame

Ranting perhaps but energy well spent and we certsinly can't scoff at ENERGY. I appreciate your time to encourage me and there is so much you say that I relate to.

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