Monitor an overactive thyroid (hyperthyroidism)

Manage and improve your thyroid function with a home blood test, personalised insights, and GP advice.


What is an overactive thyroid?

Your thyroid gland produces hormones that help control your metabolism. These hormones are:

  • thyroxine (T4)
  • triidothyronine (T3)

If your thyroid gland produces too many of these hormones, it's called hyperthyroidism (or an overactive thyroid). 

Symptoms of an overactive thyroid

Raised thyroid hormones over-stimulates your metabolic functions — meaning it “speeds” up many of your bodily processes. This can lead to symptoms like:

  • weight loss
  • heart palpitations
  • irregular periods
  • irritability or anxiety
  • difficulty sleeping
  • diarrhoea 
  • sweating or feeling warm 
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Accurate home blood testing, doctor's report and evidence-based advise for overactive thyroid support

Monitor an overactive thyroid with a blood test

A blood test can measure your thyroid hormone levels to see if it’s because of an overactive thyroid. It can also check to see if you’re getting the nutrients you need to support your thyroid function.


Thyroid hormones

Thyroid hormones include T3 and T4. Another important hormone is thyroid-stimulating hormones (TSH) — this controls the production of T3 and T4. If your thyroid gland is overactive, your T3 and T4 levels increase. While your TSH levels drop. 


Thyroid antibodies

Thyroid antibodies can sometimes cause an autoimmune thyroid disease — where your body mistakenly attacks your thyroid gland. This can lead to If an overactive thyroid. This is commonly caused by a condition called Graves’ disease. These antibodies include thyroid peroxidase antibody (TPO) and thyroglobulin antibody (TGAb).


Vitamin B12

Vitamin B12 supports your nervous system, as well as the formation of red blood cells. If your thyroid condition is caused by an autoimmune disease, you’re more likely to have another autoimmune condition like pernicious anaemia. This affects your body’s ability to absorb vitamin B12 and can lead to a deficiency. 



Folate, also known as vitamin B9, is needed for a healthy liver, as well as healthy skin, hair, and eyes. Research shows that treatment for an overactive thyroid, like medication or surgery, might increase your risk of low folate levels. So it’s worth monitoring your levels. Symptoms of a deficiency may include feeling tired, pins and needles, and shortness of breath.


Vitamin D

Vitamin D deficiency is linked to thyroid disorders. Some research suggests that low vitamin D levels can affect your immune function, which could increase your risk of an autoimmune thyroid disorder developing. A deficiency is also linked to tiredness, low mood, bone and muscle pain, as well as getting ill more often than usual.



If your iron levels are low it might affect your thyroid function. Some research suggests it can increase your risk of developing an overactive thyroid.

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Megan's plan

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Megan has an overactive thyroid and is taking medication for her condition. She regularly tests her thyroid hormones to keep track of her thyroid function. As well as vitamin D to ensure she has optimal levels to support her immune function.

Want to monitor your thyroid health?

Monitor and improve your thyroid health by taking the first step with a home blood test.

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