How much

[posthinking01]

Hi everyone - can someone run past me again how much T4 you should take by Kg weight please.

Thanks

[CreakingGate47]

After a TT, the rule of thumb is to dose patients with 1.6 mcg per kg as a starting dose and then adjust up /down by testing every 6 weeks.

It’s by no means set in stone as a guide to dosing, although appears to be evolving as such on some forums. Individuals have differing hormone requirements

[SlowDragon Administrator]

and possibly less as we get older

But again that varies

[helvella]

I wrote a blog which discusses dosing by weight and the many variations of formula that exist.

Remember, it is not how much you SHOULD take. It is more an estimate of how much might be the minimum needed - hence what some doctors might prescribe as a starting dose. But only those who agree with the approach!

helvella - Estimating Levothyroxine Dose by Weight

This blog has been revised and converted to a PDF document. This is because a PDF has far more flexibility and is easier to maintain. Plus, once downloaded, you do not need to be online to read the PDF.

A discussion about the use of formulas to estimate levothyroxine dosing. Includes link to a downloadable spreadsheet which calculates several of these.

Direct link to helvella's discussion document:

dropbox.com/scl/fi/3mmdr6h9...

helvella's calculation document and spreadsheet can be can be found by following this link:

Direct link to spreadsheet:

dropbox.com/scl/fi/1gro7whv...

Last updated 30/03/2025

Link to blog:

helvella.blogspot.com/p/hel...

[posthinking01 in reply to helvella]

Thanks for this much appreciated.

[CreakingGate47 in reply to helvella]

Very useful information and much appreciated. Thank you.

[BenLabrador in reply to helvella]

Thank you Helvella this is most useful.