Why you should self-monitor when you are being treated for an underactive thyroid

self monitoring your underactive thyroid
on Wed 28 Aug


Levothyroxine has been the “gold standard” treatment for hypothyroidism for many decades and is one of the most frequently used medications in the Western World.


However, the thyroid is a truly amazing organ which takes its cues from your entire body in order to give you just the right dose of hormones. Taking the same dose of medication on a daily basis is not that sophisticated since our bodies simply do not stay in the average zone and we forget that things that happen to our body or which we put into our body have an effect.


As a result you can have a mismatch between what your body needs and what you are prescribed.  For this reason it is important to rely upon yourself for good thyroid health on a daily basis rather than simply rely on regular visits to your GP or Endocrinologist


Let’s look at some of the things which can undermine the effectiveness of your Levothyroxine.


What time are you taking your Levothyroxine?

I have written a blog post on this previously but the usual advice for best absorption is that it should be taken on an empty stomach 30 minutes before breakfast.


However, some people find it easier to take in the evening due to convenience or tolerability - in which case it should be taken 3 or more hours after dinner - and those on a shift may have to devise their own regular schedule avoiding meal times.   The main thing is to take it with water at a time when your stomach does not have to digest food.


According to the American Thyroid Association taking Levothyroxine with or too soon before or after a meal or snack could reduce absorption to 64%, from a high of 80%


In one older but often-cited Italian study researchers found that people whose thyroid numbers were not in control despite taking thyroid hormone improved their numbers within a month by taking their medication 60 minutes before their morning meal rather than their habitual 15 to 20 minutes before breakfast.


So just changing your timing could bring your thyroid levels back into a normal range.


How recently did you start on Levothyroxine?

You will not be put onto your optimal dose straight away but on a low dose which is gradually increased. During this time you will be asked to attend for regular thyroid tests every 6 to 8 weeks until your thyroid function tests return to normal and your GP judges your dose to be satisfactory.


Even then it may take some months for your symptoms to improve as I explain in this blog post


Have you set up a system so remember to take your Levothyroxine every day?

If you miss out a dose of Levothyroxine don’t worry, thyroxine is stored within the body so you probably won’t notice any difference if this happens now and then.


If a dose is missed on one day you can always take double the dose the next day. If you take double the dose one day you can miss the dose the following day.


However, it is important to take the tablets consistently as this can affect your blood test results and your health. Try and devise a system to help you take them every day.


How are you storing your Levothyroxine?

Levothyroxine tablets may deteriorate if subjected to extreme temperatures so are best kept in a cool place within the home. Make sure you consider the storage temperature if you are going abroad into hotter climes for any long period of time.


Have you started taking any other medication?

Over the counter antacids or supplements containing calcium or iron can affect the absorption of Levothyroxine so it is wise to check with your Pharmacist at the time of purchase.  According to studies such medication should not be taken within 4 hours of taking your thyroid treatment 


Other medications can also have an effect such as metformin, lithium or amiodarone so you should work with your GP to review your Levothyroxine dose if you are newly taking these.


Did you know certain foods can affect the effectiveness of Levothyroxine?

Studies have shown that drinking coffee at the same time or shortly after taking your Levothyroxine can significantly lower the absorption of the thyroid medication in your intestine.  The caffeine in coffee is believed to be the cause of this. 


Soya can also interfere with absorption so you should adopt the recommended gap between taking the Levothyroxine and digesting foodstuffs for Soya milk as well.


Have you developed another medical condition?

Something called The CONTROL Surveillance Project looked at a number of factors known to compromise levothyroxine efficacy and tolerability. This showed that certain conditions, medications and dietary habits may be more prevalent among treated hypothyroid patients than was generally understood 


Conditions which may affect the efficacy of Levothyroxine includes

  • Coeliac disease
  • IBS
  • Lactose intolerance
  • Gastritis
  • Helicobacter pylori (a common cause of peptic ulcers)


Have you put on or lost a lot of weight?

Most patients require between 100 and 150mc but the dose can be lower than 75 mcg or up to 300 mcg a day depending on your needs


It is perhaps easy to forget that your dose has been recommended on your blood test results in combination with your weight. ..


Are you going through a particularly stressful period in your life?

Although the link has not been proven, some experts have speculated whether stress can affect your TSH levels. This is because the hormone produced in response to stress can suppress your pituitary function and prevent the thyroid stimulating hormone (TSH) from being released.


Are you aiming to conceive, are pregnant, or have just given birth?

Your body is subject to enormous change and hormonal fluctuations during pregnancy and for this reason it is vital to work more closely with your GP who will certainly want to monitor you on a more regular basis.


The current recommendation is  four weekly appointments. In view of the fact that many GP surgeries are under considerable pressure in terms of availability of appointments I would recommend you book these up in advance at the beginning of your pregnancy.


You will be put on an increased dose of Levothyroxine during pregnancy in order to support the development of the baby. You should then make an appointment with your GP 6 weeks after the birth to avoid overdosing on Levothyroxine which could make your hyperthyroid.  It is likely that you will go back to your pre pregnancy dose at this point.


Have you entered Menopause?

It is possible for menopausal symptoms to be confused with hypothyroid symptoms, so consider this rather than decide that your thyroid medication is not working.  For example:

  • Problems on focusing and learning whilst in menopause could be confused with poor memory in hypothyroidism
  • Changes in energy when menopausal can be confused with persistent fatigue when menopausal
  • A sudden increase in weight /body fat can happen in both conditions
  • Menopausal mood swings can be confused with anxiety or sadness attributed to hypothyroidism


How often should you be checked?

Under normal circumstances make sure you have your TSH levels checked around every 12 months.


Is there a best time to take this test? Current research suggests that TSH levels peak between 2am and 4am and decrease to their lowest levels at between 4pm and 8pm so you would be best to make a morning appointment each time.


If you believe your medication is no longer working effectively it will be helpful to your GP if you have kept a track of your symptoms and health trends over several months.


When should you see an endocrinologist?

There are 5 main reasons for asking to be referred:

  1. Your symptoms fail to improve despite treatment
  2. You have a thyroid lump or nodule
  3. You have an enlarged thyroid gland or goitre
  4. A pituitary gland disorder is causing your hypothyroidism
  5. You are pregnant or trying to conceive


I do hope this has been helpful.




Although every effort is made to ensure that all health advice on this website is accurate and up to date it is for information purposes and should not replace a visit to your doctor or health care professional.


As the advice is general in nature rather than specific to individuals Dr Vanderpump cannot accept any liability for actions arising from its use nor can he be held responsible for the content of any pages referenced by an external link







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