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can someone please help me figure my initial dose of levothyroxine

can someone please help me figure my initial dose of levothyroxine i had a complete thyroidectomy earlier today, i m 54-year old male, i weigh 84 kilograms, i am 1.8 meters in height. what would be my initial dose of levothyroxine using the BMI formula, thank you very much,

Sincerely Eric DeSonie

7 Replies


You might care to try my spreadsheet:

It will work in Excel and quite possibly in other spreadsheet programs (ir is pretty simple). Don't take any of the suggestions it makes as gospel. All formulas are deeply questionable. And all doses are likely to need revision as soon as their effects can be felt or measured.

Do, please, read the comments in it!

1 like

im in the hospital and i dont have a way to pay for it right now, my Dr has not started me on nothing yet and my surgery was 11 hrs ago they gave me a chewable calcium tablet that is all



Calcium levels can drop after surgery.  Mine normalised after a week.


Hi Eric and welcome to our forum.

I am sorry you have had a TT and hope your recovery will go well.

I do hope the endocrinologist will add T3 to whatever dose of T4 (levothyroxine) he prescribes as T3 acts faster than T4 which has a long half life. Even though T3 is fast it goes directly into our receptor cells and its effect lasts between 1 to 3 days. Modern Endos seem unaware of this fact.

Best wishes. 


Welcome to the forum, Ericdesonie.

I don't think dose to weight ratio is often used now but 1.6mcg x 84kg = 134.4mcg and the nearest dose to that in the UK would be 137.5mcg Levothyroxine.  6-8 weeks after starting Levothyroxine blood levels should be checked and dose adjusted if required.

If your thyroidectomy was because you have thyroid cancer the starting dose may be higher in order to suppress TSH.  The morning after surgery I was given the equivalent of 200mcg Levothyroxine which was unrelated to weight 54.6kg.  The hospital gave me 28 days medication to take home and my GP issued repeat prescriptions thereafter.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


This morning, I tried to pass information on as I was getting ready to go to work. Not ideal!

I return to the thread to add several things:

It is reassuring that you have managed to post here within such a short time of your operation. I'm sure we all wish you the very best in your recovery.

Why did you have the thyroidectomy? If you have Graves, for example, your treatment prior to the operation will have a very important impact on your need afterwards.

My spreadsheet offers several possible doses based on your input data:








Hmm. That makes it easy! What I call the Wisconsin formula, which does indeed base itself on BMI, gave 139 micrograms per day.

Please DO read the warnings and explanations in the spreadsheet when you can.


When I was in hospital after my thyroidectomy I was only given 100levo and told that's all anyone needs(!!) I'm now on 150 ,the formula yr talking about worked out to 155 for me at that time although hve put weight on since.

Oh and don't take levo with yr calcium (usually given to you at same time in hospital)  they need to be 4 hours apart and depending on diff advice about 2 hours fm food or caffeine.

Take it easy after yr TT, it is classed as a major op so rest up  x


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