Updated: Mar 30
Symptoms of an underactive thyroid include:
weight gain or difficulty losing weight
feeling cold or getting chilled (may not be noticed at menopause)
depression and apathy
dry skin and hair
lateral eyebrow thinning
getting sick more frequently
body aches and pains
If you are currently taking thyroid medication (Levothyroxine – with brand names Synthroid or Eltroxin), your blood levels are in an optimal range, but you still have thyroid symptoms we need to dig deeper into the cause. Thyroid medications are quite simply thyroid hormone replacement, providing extra free T4 (thyroxine) to the body to make up for what your thyroid gland is not producing itself.
If you’re still feeling sluggish on thyroid medication, here are my top factors to investigate:
Your dose of thyroid medication may be too low
An optimal range for TSH is between 0.8 – 2.5 mIU/L, and free T4 12-17 pmol/L. If your TSH is higher and your free T4 is lower than this, it means that your medication dosage is not yet optimal.
Poor conversion of T4 to T3
If your TSH and free T4 are both in an optimal range, it is important to also test for free T3 levels to ensure that your body is utilizing and converting the hormone optimally. T3 or triiodothyronine, is the activated form of thyroid hormone. It is not present in levothyroxine medications so your body needs to do this conversion. If your free T3 level is low, you will still have all of your original hypothyroid symptoms.
Autoimmunity (elevated thyroid antibodies)
This is perhaps the biggest factor on the list, and one not at all addressed by conventional medicine. The most common cause of hypothyroidism is an autoimmune condition called Hashimoto’s thyroiditis. In this case, your immune system is attacking the thyroid gland causing it to gradually become damaged and lose functionality. In the case of any autoimmune disease, there is inflammation in the body, which creates global symptoms such as fatigue, body aches and pains, low mood and general malaise. The first step to confirm if you have Hashimoto’s is to test for thyroid antibodies (anti-thyroglobulin and anti-thyroperoxidase antibodies).
Your body is stressed
This is actually connected to point #2 – poor conversion of T4 to T3. When your body is stressed, there is a slower conversion of T4 to T3 in the body, which is your body’s way of slowing down your metabolism to force you to rest and repair. It is important to remember that this is a protective mechanism, not a malfunctioning system. Stresses that can set off this pattern include: emotional stress, lack of sleep, poor blood sugar control, over-exercising, under-eating, chronic illness and infections.
You may be taking your thyroid medications wrong
To get optimal effect from your thyroid medication, it is important to take it at least 1 hour away from any food and drink (except water). It is also important to take it 4 hours away from iron, calcium or multivitamin supplements, as well as oral contraceptives containing estrogen.
All of these factors can quite simply be tested with basic bloodwork, and then the goal is to treat the cause. This may mean adjusting medication dosage, adding T3 (Cytomel), switching to desiccated thyroid (which contains T4 and T3), treating autoimmunity, addressing stress levels, supporting adrenal health, or providing extra nutrients for thyroid function.
Remember the first step is to test to understand why, and from here it’s quite simple.
So if you’re still feeling unwell while taking thyroid medication, there is hope – a well-treated thyroid should get your metabolism, energy, mood and vitality back to optimal again.
McAninch EA, Bianco AC. The History and Future of Treatment of Hypothyroidism. Ann Internal Med. 2016 Jan 5; 164(1): 50-56.
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