Selenium vs T3 re conversion

I have read tons about how Selenium helps with conversion of T4 to T3 and is generally a good guy re: thyroid function.

I am currently self medicating 75mcg levothyroxine, 50mcg T3 and 200mcg Selenium and due to problems with payment systems I am considering dropping the T3.

Just wondering if anyone else out there dropped T3 for Selenium and is doing well since

32 Replies


200mcg selenium may improve T4 to T3 conversion but it is not a substitute for T3. 50mcg T3 is roughly equivalent to 150mcg Levothyroxine. If you are going to stop taking 50mcg T3 you will need to increase your Levothyroxine dose.

150mc levothyroxine is way over the heart has a hissy fit on that level...I'm thinking I should stop the T3 altogether then. I have already had a cardiac arrest this year and several days in a coma due to my chronic heart failure...I really don't want a repeat performance


Of course not. Do you know what your FT3 level is on 150mcg T3 + 75mcg Levothyroxine.

No idea...i have only had t4 and tsh levels tested since the 80's when this all started. Even in hospital they only treated the low t4 feedback from the hospital since I was discharged on April 1st this year


If you want to check your FT3 you can order a thyroid home test finger prick test from Blue Horizon or Genova via

I know...but I don't have £145 going spare only income is very low so I think I need to work harder to pay for it

Just is £139...


Have a look at BH Thyroid Plus 6 which costs £69.

Excellent!!!.....added to my wish list :)

what caused the coma do they know? is it too much meds or an underlying heart issue from past thyroid issues untreated?

I have had chronic heart failure (with obvious symptoms) since around 1980 and diagnosed in the early 90's by a cardiac doctor working in private practice.

It was explained at the time what was making my symptoms worse was the levothyroxine and I was advised to take tiny amounts or none at all.

I was put in a therapeutic coma while the hospital staff were trying to work out what was going on with me. I came out of the coma for a few minutes then went into a coma all by myself.

I have had no follow up appointments so have no idea why I was so ill

why haven"t you been to see a dr after all of this I don't understand?

I don't have any faith in the opinion of the health professionals in the town where I live as they haven't helped me in the more than 2 years I have lived here. I prefer self testing and only see an NHS doctor for prescriptions that I request

you cannot travel outside go your town?

No...I am a full time carer for my partner and he can't travel without being in a lot of pain. He had a leg amputation nearly 3 years ago and despite being on opiates and other pain relief he is still in too much pain to travel

I am really very sorry your are having all of that on your shoulders especially when you do not feel well as well & I am extremely sorry for him. God bless, I had no idea.

but if she does not convert at all or properly she shouldn't stop it at all right?

Selenium is needed for T4 to T3 conversion but I suspect selenium deficiency is rare in the UK. If there is not enough selenium to make the deiodinase molecules then it will affect deiodinase in the pituitary. The pituitary is reliant on deiodinase to convert T4 to T3 for its T3 receptors. Hence if your T4 to T3 conversion is affected by selenium deficiency your TSH will be very high.

You are on a high dose of thyroid hormone. If you have cardiac problems I'd take the minimum dose.

"You are on a high dose of thyroid hormone. If you have cardiac problems I'd take the minimum dose."

I was advised to cut levothyroxine out all together when the cardiac prob was diagnosed as the consultant suspected the low levels of T4 was my body trying to prevent cardiac arrest by slowing down the thyroid. Made total sense at the time but no-one I saw on the NHS has run with it....

I don't believe the body reduces T4 levels to protect the heart. There is however 'low T3 syndrome'. During and for a while after a heart attack the body reduces T4 to T3 conversion. Nobody knows whether this is 'protective or pathogenic', in plain English whether it protects the heart or makes things worse. If it were me I'd take levothyroxine if I needed it to obtain normal TSH and fT4 levels.

we'll have to agree to disagree regarding the reducing of T4 levels to protect the heart as it was my cardiac doctor who told me this. This was back in the early 90's and my only cardiac arrest was brought on by repeated viral infections. The lowered T4 level was connected with my heart overworking while my immune system tried to zap the bugs

Our understanding of thyroid hormones following cardiac incidents has progressed a lot from the 1990s. The major effect after an acute coronary incident is a reduction in fT3, an increase in rT3 and a much smaller reduction in fT4. These are short term effects.

I wasn't suggesting you increase your fT4 levels, just keep them normal if they are low. The same applies to fT3, it this goes too high it places a strain on the heart.

The heart is able to convert T4 to T3 and reduces its rate of conversion in hyperthyroidism thus protecting itself, so levothyroxine is safer than liothyronine.

I understand that about the after effects of a cardiac arrest and the drop in t3 levels as I researched that when I was sent home with a bottle of t3 and no-one at the hospital had explained why. My GP was sent the results of an echocardiogram I had a few days before I came home and the results back up the heart failure diagnosis back in the 90's which is why I am self medication...the NHS staff here in Eastbourne don't seem to be interested

GosportNANcy if you feel good on T3 i would not drop it. I would find another way. In have been on selenium and other" thyroid supporting " vitamins and minerals for quite some time and my conversion has not changed. Still low on T3 while being medicated. From research i have done, everything says most people do better with T3 added either because of not converting or not enough.

I was put on T3 as a temporary measure while I was in a coma following multiple organ failure and a coma. My T3 levels have never been tested and until I have some evidence of low T3 I am not happy messing about with my hormones.

have you requested they test your T3???

No...I don't see any health professionals to ask but I am planning on doing a home test once I have been on the new supplement regime for at least six months

You didn't mention your reverse T3 levels. If you haven't had that analyzed, you should. If your RT3 (reverse T3) is high, taking T4 medication is like throwing gasoline on the fire.

I had the same problem and kept taking more T4 meds and getting fatter, losing more hair and getting sicker. Once I discovered the culprit, I lowered my desiccated thyroid dosage (Armour) and added T3 meds (Cytomel).

I also added 2-4 Brazil nuts daily (I can't take Selenium; it makes me sick). I also added Magnesium and Zinc, two important minerals that also help with conversion from T4 to T3.

I felt infinitely better, lost weight and got my hair back. Hope this helps!

Hi..I asked the GP about T3 testing and she said the only test she does for thyroid hormones is to measure the TSH. My TSH was 7 in November last year.

I don't have the funding for home testing so I have to play it by ear. I have recently been diagnosed with a cardiac condition so don't want to mess with my thyroid until my heart function is more stable...multiple organ failure, cardiac arrest and several days in a coma last year puts my heart right at the top of my list of priorities right now

Get a new doctor. They should absolutely test your T3, T4 and TSH if you are taking T3. A TSH of 7 is way too high - a level of 1 is usually optimal for most people it seems.

Try Vale hospitals. They have a thyroid clinic and are able to try treatments that NHS surgery doctors cannot.

Also, I am trying NDT (Armour) for the first time and switching off my T4 and T3 combo. I hear it can help those who do not do well on levo. My endo says that medical science has yet to catch up to why NDT works for some people. He said that it's possible we haven't quite figured out what a deficient thyroid needs. So you may want to look into this. NDT typically has less T4 and more T3.

All of the GPs locally read from the same hymn sheet and to see another doctor I would have to move house to be within their catchment area;

I am on a very low income, so travel costs and private help is not an option.

I am not taking T3 now as I ran out and cannot get any more prescribed.

I take Co-enzyme Q10 at the advice of a cardiologist and on doubling the dose I was on am now feeling a lot better

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