What is a high dose of levothyroxine?

[JazzyRJ91]

Hi there

I’ve been diagnosed with an underactive thyroid for about 12 years. I take 175mcg daily, and have for about 10 years.

What is considered a “high dose”?

[ILR2019]

There is no 'one size fits all' with regards to treatment and I would question if a high dose is even a viable question purely because a dose that relieves symptoms and makes you euthryoid is going to be your optimal dose whether that is 50mcg or 300mcg. That optimal dose will be different for everyone based on so many factors. Why do you ask?

[SlowDragon Administrator]

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also EXTREMELY important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies

Ask GP to test vitamin levels

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Add results and ranges if you have any

Or come back with new post once you get results

[tattybogle]

a few decades ago( i've read) it was more common to be on doses of 200+ even 300. I think the Tests machines for TSH have become able to measure accurately down to much lower numbers nowadays and this is part of the reason for average doses being lower today. Between 100-150 seems very common from what i see on here. So 175-200 is probably considered 'high' by some of todays GP's.

but if you feel well enough on it i wouldn't be concerned.And i wouldn't let it be lowered without a good reason that you've done your own 'fact checking' on.

i'm starting to wonder if GP's are being fed the line that '100 is enough for most people' . There was something in the way that my GP shouted 'the dose is 100' at me last year that sounded like he'd read it.

[tattybogle in reply to tattybogle]

Years ago when i was on 150 levo and it (sort of) worked for me , i asked my auntie who was on it how much she took..... 250.. which at the time just fed into my 'theres nothing much wrong with me then, i'm just moaning about nothing' mentality...... after all the Doc had said my results were normal now .

With hindsight i remember that she told me she hadn't been for a blood test for years because she didn't need to, because she felt alright.

Now i know what i know now , i wonder if she would have been put on a lower dose today, and not felt so alright.

[Hidden in reply to tattybogle]

I´ve been told the same thing by doctors...that is, that you should never need more than 100 mcg of levo daily as that is how much T4 a healthy thyroid gland produces on average in a 24 h period. However, I´ve read that levo is rather poorly absorbed from the gut...somewhere between 60-80% depending on nutritional and gut status. So, if you swallow 100 mcg of levo and wait at least an hour before eating, you may not be absorbing more than 60 mcg...so way less than the 100 mcg your doctor assumes you´re getting just by taking a 100 mcg pill.

Another proof to me to go by symptom-relief rather than strictly adhering to labs.

[tattybogle in reply to Hidden]

Plus , i now know (from the 'Pilo' study that there's a huge range of healthy thyroidal T4/T3 ratios.

size 5 shoes are probably 'average', and i can fit in them..... but i wont be able to walk far before i get crippling blisters on my right foot.

[Hidden]

I’m on 250 - was on 100 for decades but things went haywire last summer. GP says they have patients up to 300 (tho rarely). HTH

[Despena]

You could say that I am on an extremely high dose as I take a 1000 (yes one thousand) mcg a day but that works for me, anything less and I’m feeling it. If 175 mcg works for you then it’s not high it’s the level that is good for you, and as ILR2019 says it’s not one size fits all, so I wouldn’t worry about it

[Hidden]

I recently read that before today´s lab measurements were invented, and doctors dosed patients by symptom-relief, it was not uncommon to find patients on 200-400 mcg of levo daily. If you have some kind of thyroid hormone resistance, you will need more (just like some people need 8-10 grains of NDT or 150 mcg of T3 daily).

What others do well on really isn´t important...it´s all about how you feel. Symptom-relief is the best way to judge how successfully you are treated, in my experience. It would seem what´s important is what happens to thyroid hormone on cellular level, and that cannot be measured in blood...which would explain why patients tended to take more thyroid hormone before today´s "ultra-sensitive" TSH test was invented.

I have had doctors tell me that nobody should take more than 100 mcg of levo daily because that is apparently what a healthy thyroid gland produces (along with some T3). But if you take 100 mcg of levo orally, that does not mean that 100 mcg will be absorbed and usable to the body...more likely 60-70%. So, in order to absorb 100 mcg of levo, you´d need to take close to 150 mcg. Another reason IMO why many patients are under-treated so basically kept hypothyroid. It seems T3 is better absorbed (ca 90%) than T4, so that also needs to be taken into account.

[helvella Administrator Thyroid UK in reply to Hidden]

Even if we absorb a lot of the levothyroxine we take, how it is treated within the body might vary.

When we take a levothyroxine tablet, FT4 usually peaks around two hours later. On a steady daily dose, that peak will inevitably be somewhat high. Our bodies might well excrete at least some of that as the sulphated or glucoronidated forms of levothyroxine, (These are standard pathways we all have which seem to allow relatively safe disposal of excess thyroid hormone.)

Some of us might do this to a greater extent than others. This could result in seeming to need a higher dose.

[Hidden in reply to helvella]

Not that most doctors would understand that...most treat the TSH, not the symptoms

[dtate2016]

I agree with purplecat71 and Tattibogle. Here in the US doctors who know just a little bit about Hashimotos and let me emphasize little bit - They talk about conversion of T4 to T3. Some of us convert better than others hence that could account for the 70 to 80% that you’ve been hearing from some of the others. One must be able to convert T4 to T3 to be optimal.

The fact is many of us don’t convert well. I’m One of them. For 30 years I was able to get my hands on a really nice pharmaceutical grade porcine T3 /T4 blend. It worked really well For all those years, and then one day, it stopped working.

Long story short, I had to search high and low to find a clean source of T3 to take along with my levothyroxine. And I did all the things the gurus say to do like gluten-free and dairy free and on and on. It’s kind of sorta maybe worked - I mean I know I felt better from time to time. There are many ways to approach this conversion problem and the liver is at the heart of The conversion problem.

Most recently I found that estrogen is what they call a Hashimoto’s (causing, trigger) hormone. It’s the bad estrogen its the dirty estrogens - that we get in food and maybe one reason why women have Hashimoto’s more than men. Found research that said taking progesterone along with vitamin E will help our liver detox the bad estrogens and and help our liver begin to convert T4 to T3 better. Where to find a non-pharmaceutical grade of progesterone was my next hurdle. I found it and it’s not even that expensive and I can’t tell you how wonderful life is. I can eat gluten and dairy and drink wine again and have alcohol which by the way contains some of the bad estrogen’s! I’m also taking a proteolytic enzyme that likewise helps the liver detox, also lends itself to the conversion of T4 to T3. If the liver is healthy levothyroxine works well. If it’s struggling under an estrogen toxic load then it just can’t do it all. And you can take, yes, 1000 mcg of levothyroxine and still not get enough T4 and T3 Conversion / delivered to the cellular level where you need it. And yes the blood test would show up deficient.

Ray Peat, PhD, I learned about him here - has long talked about the progesterone need for those with thyroid disorders. LONG! He’s right. There’s more than one way to approach T4 T3 conversion and you can do the elimination diet’s if you want to, and I did. But this way is much better oh my, so much better you feel so much better. I take 75 mcg of levothyroxine and about 35 mcg of bovine T3 desiccated thyroid. I’m also taking a clean source of collagen which gets rid of damaging bad proteins - makes the skin look beautiful and hair and nails! All of this supports the liver, supports T4 T3 conversion, reduces puffiness and bloating. It took a long time to find this route, but I am so happy! Highly recommend looking up Thyroid Revolution - lots of free information there about the progesterone hormone balancing estrogen (even in men!) and how come we’re still hypo even when we take levothyroxine. I used to think Isabella Wentz had the corner on alternative remedies to Hashimoto’s - and she has some great ideas - i’m guessing they work well for some. Thyroid revolution is a whole Nother depth of research and another approach to healing the liver and balancing the hormones including the thyroid hormones.

I know this is long and I hope it helps - hang in there I think we’re so close to finding the answer to autoimmune disorders!

[wellness1 in reply to dtate2016]

Glad you are feeling well. May I ask which brands of collagen and proteolytic enzymes you are taking?

[dtate2016 in reply to wellness1]

The Collegen is from Forefront Health. The enzymes are called Phy-Zymes.

[Hidden in reply to dtate2016]

Can I ask which brand of progesterone you are taking? I have been on HRT for a few years now (bio-identical transdermal estradiol and Utrogestan (called Prometrium in the US) but I find the latter not to be very effective...about a year ago, I switched from taking it cyclically to continuously (100 mg daily at bedtime instead of 200 mg twelve days a month) but really felt no difference. My progesterone levels are at the bottom of range so I am technically estrogen dominant which could explain some of my symptoms. But the only solution I have found so far (by visiting US websites) would be to go off estrogen altogether and take 300 mg of Utrogestan daily.

Some US doctors, like Christiane Northrup, say that women in Western societies rarely are truly estrogen deficient as we constantly absorb estrogen-like substances from plastic, cosmetics, beauty products...so most are in fact progesterone deficient and would benefit from progesterone supplementation rather than estrogen even in menopause.

It would seem that progesterone only, if taken at high enough doses, can be as effective for hot flushes (my main problem) as estrogen, but without the side effects.