The thyroid gland, which is found in the neck, produces thyroid hormone. Thyroid hormone is a bit like the body’s “throttle” in that it drives our metabolism and other aspects of physiology. Various thyroid conditions can lead to an excess or a deficiency of thyroid hormone, these being called hyperthyroidism (excess) and hypothyroidism (deficiency). The topic rapidly becomes quite complex and a lot of the detail is confusing and or excessive for most of us, so this article just aims to help you understand what hyper and hypo-thyroidism might look like.


When you have insufficient thyroid hormone the effects are all about the body slowing down too much, and include:

  • Weight gain (from slowed metabolism)
  • Slow heart rate
  • Feeling cold
  • Weakness
  • Fatigue
  • Constipation
  • Depression and or low mood
  • Thin dry hair and nails


Excessive thyroid hormone “drives” the body too fast and the effects include:

  • Weight loss (from fast metabolism)
  • Rapid heart rate
  • Feeling hot
  • Fatigue
  • Sweating
  • Diarrhoea
  • Agitation and or anxiety
  • Tremor
  • Insomnia
  • High blood pressure

So as you can see, the symptoms are more-or-less opposites, and you can see how the effects of too much or too little are a bit like what you’d expect with too much or too little “throttle”. Simple blood tests can be done to check thyroid hormone levels so reaching an initial diagnosis is not complicated.

Please note: there are many and varied causes for too much or too little thyroid hormone. Possible causes include autoimmune conditions, cancers, infections, and primary thyroid conditions like Graves Disease.

It is worth knowing about these symptoms so that if you do suspect your thyroid is over or under active you can see your doctor for some simple tests, and go from there.