Thyroid UK
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Does anyone know what the level of thyroxine is needed when TSH level is 8.6

I have been on 50mg of levothyroxine for 4 years since I was diagnosed as having an underactive thyroid following the birth of my son. I have since suffered terrible joint pain and muscle spasms almost everywhere (but especially my lower back ( which keeps me awake every night). I have recently had a blood test and the results came back that my TSH level is 8.6.

My doctor has now upped my dosage to 100mg and told me to get re-tested in three months time. Do you think this dosage will be right for this level, and have chronic back pains improved in anyone with a similar experience to mine. I'd very much appreciate anyone's views,

Many thanks


6 Replies

You really need more than the TSH tested - that is a small part of the story. You need to know the FT4 & FT3 levels and the anti - bodies TPO & Tg.

The TSH needs to be 1 or under when medicated - so how do you take your meds ?

How are your levels of B12 - Folate - Ferritin - VitD ? All need to be OPTIMAL for you to feel well and for the thyroid hormones to work in the body.

Lower back pain can be due to muscle weakness due to LOW T3. The biggest muscles in the body are in the butt 😊

Things will improve when you are optimally medicated ....

1 like


I think 100mcg will be ample. It takes 7-10 days for a Levothyroxine dose increase to be absorbed before it starts working and it will take up to six weeks to feel the full impact of the dose. Symptoms may lag behind good biochemistry by several months.

You should have a follow up thyroid test 6-8 weeks after increasing Levothyroxine. Arrange an early morning and fasting (water only) blood draw when TSH is highest, and take Levothyroxine after your blood draw.

Ask your GP to test ferritin, vitamin D, B12 and folate as low/deficient levels can cause musculoskeletal pain and fatigue similar to hypothyroid symptoms.

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Change your GP immediately

50mcg is a starter dose and you should have been tested every 6 weeks and dosage adjusted upwards

its vital that




vit d3

are also tested as they must be at least halfway in their ranges otherwise your body cannot utilise the levothyroxine

always ensure all tests are early morning

fasting drinking only water

Never never never take levothyroxine in the previous 24 hours

Always ensure you get the actual figures and ref ranges and keep a file

then you can see problems occuring


Thank you so much for your reply. I will take your advice on board. I have recently moved so I need to change doctors anyway. I have asked for details on my blood tests so many time and always get the same response, either "normal" or "not normal." When I asked the doctor what he regards as normal, he was very rude and just repeated the same thing. I've asked for my blood results to be sent by email and had no response. Feel like they don't want me to know. I only found out this time by getting a fleeting glance at the doctors computer. Anyway, thanks again, it was so kind of you to respond, much appreciated,




Your GP is arrogant ignorant and downright negligent email for copy of PULSE article written by Dr Toft specifically for GPs then you will know how a good GP should act


Thank you for taking the time to message me and for the info, I shall follow your advice.


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