Thyroid UK
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Trying to work out what my correct dose should be

Hi I am new. I am trying to work out what my correct dose should be but it's very hard to judge with all the sweating and sleep problems I keep getting.

Could anyone please help. I stopped my levo 2 days ago and reintroduced 50mcg as of yesterday.

Diagnosed in 2012.

Thank you!

Dec 2017 - 150mcg levo

TSH 6.3 range 0.27 - 4.20

Free T4 13.9 range 12 - 22

Free T3 3.1 range 3.1 - 6.8

16 Replies

It seems to me as if you cannot convert levothyroxine into sufficient T3. T4 (levothyroxine) is T4 only. It's job is to convert to T3. T3 is the only Active thyroid hormone required in our millions of T3 receptor cells.

I believe that you need a combination of T4/T3 or you can have a blood test to see if you have a defective gene - DIO2 - which proves that you cannot convert T4 to T3. You might even need T3 only.


You are extremely under medicated and very likely to have extremely low vitamin levels

Do you have results for vitamin D, folate, ferritin and B12

Posts by others showing typical low vitamin levels due to under medication, with advice from SeasideSusie on how to improve

Do you have Hashimoto's also called autoimmune thyroid disease diagnosed by high thyroid antibodies?

Dose should be increased by 25mcgs steps, retesting 6-8 weeks after each dose increase until TSH is around one and FT4 towards top of the range and FT3 at least half way in range

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor

please email Dionne:

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TPO antibodies 708.3 (<34)

TG antibodies 783 (<115)

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So you antibodies are very high this is Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease).

About 90% of all hypothyroidism in Uk is due to Hashimoto's

Essential to test vitamin D, folate, ferritin and B12. Always get actual results and ranges. Post results when you have them, members can advise

Hashimoto's affects the gut and leads to low stomach acid and then low vitamin levels

Low vitamin levels affect Thyroid hormone working

Poor gut function can lead leaky gut (literally holes in gut wall) this can cause food intolerances. Most common by far is gluten

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find gluten free diet helps significantly. Either due to direct gluten intolerance (no test available) or due to leaky gut and gluten causing molecular mimicry (see Amy Myers link)

But don't be surprised that GP or endo never mention gut, gluten or low vitamins. Hashimoto's is very poorly understood

Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies

Ask GP for coeliac blood test first


Ok I also tested positive for anti tissue transglutaminase antibody

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Then you should have further testing for coeliac disease. Push for endoscopy asap

Even if it turns out negative for coeliac a high percentage still find gluten free diet helps or essential


So, what diagnosis and advice were you given?

Any further investigations


You have Hashimoto's Autoimmune Thyroiditis and Hypothyroidism.

These results are Hypothyroid. You need more LT4 to restore you to Euthyroid status.

See if you can get nutrients tested and sorted asap. Try not to stop and start your LT4.


Why did you stop your LT4 two days ago with such a high TSH? What advice did your doctor give after theses results and hearing of your symptoms?

As far as I am aware, dose increase or decrease should be by increments of 25mcg at a time only.

These results say that you are undermedicated. Your Pituitary Gland is producing too much TSH.

TSH is too HIGH - needs to be much lower. Your Free4 and FreeT3 are low - bottom of ranges.

These results do not indicate overmedication.

Do you have Hashimoto's Autoimmune Thyroiditis?

Do you have any Nutrients deficiencies?

Have you had Thyroid Antibodies TPO and Tg tested?

Have you had levels of Vitamin D, Calcium; B12 & Folate; and Ferritin tested?

If not,.ask GP for them asap and get any deficiency treated.

Post results with ranges and full dates of tests on here for comment.


Because I had symptoms of sweating and weight loss and insomnia I stopped it

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What did your GP say

1) about results

2) about your symptoms .

You have Hashimoto's.

Your results say that you are undermedicated and not over medicated.

Do you have any Nutrients deficiencies? On any other meds or supplements?


a) nothing said about results, told TSH was only a little high but nothing to worry about

b) nothing said about symptoms

Dec 2017

Vitamin D 50.6 (50 - 75 suboptimal. Advise on safe sun exposure and diet) taking 800iu D3 for 7 years

Ferritin 22 (15 - 150) iron stopped 2016

Calcium 2.21 (2.20 - 2.60)

Calcium adjusted 2.22 (2.20 - 2.60)

B12 250 (180 - 900)

Folate 2.3 (2.5 - 19.5) taking 5mg folic acid


TSH is far too high.

Ask for urgent referal to an Endocrinologist.


Dec 2017

Vitamin D 50.6 (50 - 75 suboptimal. Advise on safe sun exposure and diet) taking 800iu D3 for 7 years

Ferritin 22 (15 - 150) iron stopped 2016

Calcium 2.21 (2.20 - 2.60)

Calcium adjusted 2.22 (2.20 - 2.60)

B12 250 (180 - 900)

Folate 2.3 (2.5 - 19.5) taking 5mg folic acid


When did you get the low cortisol result and what were you advised by GP or Endocrinologist?



You are undermedicated on 150mcg Levothyroxine so your correct dose will be between 175mcg - 200mcg. I would reinstate 150mcg ASAP and ask your GP to increase dose to 175mcg.

The goal of Levothyroxine is to restore the patient to euthyroid status. For most patients that will be when TSH is 0.2 - 1.0 with FT4 in the upper range. FT4 needs to be in the upper range in order that sufficient T3 is converted. Read Treatment Options in Email if you would like a copy of the Pulse article to show your GP.

Sweating, weightloss and insomnia could be due to undermedication, coeliac disease which is confirmed by positive tissue transglutaminase antibodies, or low B12 You should be 100% gluten-free as you have coeliac disease. You may find absorption improves when you have been gluten free for a few weeks and Levothyroxine may need adjusting again.

Thyroid peroxidase antibodies are positive for autoimmune thyroid disease (Hashimoto's). There is no cure for Hashimoto's which causes 90% of hypothyroidism. Levothyroxine treatment is for the low thyroid levels it causes. Many people have found that 100% gluten-free diet is helpful in reducing Hashi flares, symptoms and eventually antibodies.

Positive anti tissue transglutaminase means you have coeliac disease ie gluten intolerance and should be very strict about excluding 100% gluten from your diet.

800iu is insufficient for treating vitamin D deficiency. It is a maintenance dose to be prescribed once vitD is >75. My sister's GP prescribed 2 x 20,000iu per week when her vitD was 40. Take vitD 4 hours away from Levothyroxine.

Ferritin is optimal halfway through range. I would supplement 1 x 210mg Ferrous Fumarate daily to raise ferritin. Take it with 1,000mg vitamin C to aid absorption and minimise constipation. Retest ferritin in 4-6 months. Take iron 4 hours away from Levothyroxine.

Calcium is within range.

B12 250 is low and could be deficient. If you have symptoms in go to for advice on what to ask your GP.

5mg folic acid is the correct treatment for folate deficiency. Your GP should retest in 3 months.


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