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Maximize Your Energy: Part 2

In Part 1 of Maximize Your Energy, we discussed the importance of testing for low iron and thoroughly assessing anemia (click here to read the article)

In Part 2 we will focus on the importance of healthy thyroid function in optimizing our energy levels.

The thyroid is a gland that sits in the neck. It manufactures thyroid hormones, which regulate metabolism and energy, make certain proteins and influence the sensitivity of body cells to other hormones.

When the levels of thyroid hormones drop, our metabolism becomes sluggish, energy levels drop and it becomes increasingly difficult to lose body fat.

Symptoms of Hypothyroidism (low thyroid function) include but are not limited to:

  1. Fatigue
  2. Weight Gain
  3. Feeling the, particularly in the hands and feet
  4. Constipation
  5. Dry Skin and Hair
  6. Hair loss

As with most hormones, thyroid hormone release is controlled by a delicate negative feedback loop. This is the body’s natural control mechanism to prevent the levels of thyroid hormone climbing too high or dropping too low.

The thyroid gland actually produces 2 similar hormones: T3 and T4. T3 means the molecule is composed of the amino acid Tyrosine and 3 iodine molecules. T4 implies that there are 4 iodine molecules added to Tyrosine.

T4 does not circulate in the blood on it’s own. T4 is transported by a sort of “taxi” protein (e.g thyroid binding globulin), ensuring that it has very little effect on cells at the level of the receptor.  It acts almost as a reservoir so that when active thyroid hormone is needed to accelerate metabolism/create energy, an enzyme can remove an iodine molecule and release it from the “taxi”, allowing the hormone to exert it’s effect on the cells of the body.


Occasionally, a different enzyme will remove the wrong iodine molecule from T4, making what we now call reverseT3 (rT3). Unlike T3, rT3 does not exert an effect at the receptor but blocks the action of T3.
Thus, there are many causes of an under-functioning thyroid gland. There may simply be an insufficient level of T4 being produced or a difficulty converting T4 to T3 when it is required (either because there are insufficient nutrients or because too much rT3 is being made). In some cases, the body’s own immune system may attack the thyroid gland or, the receptors on other cells of the body become insensitive to the actions of thyroid hormone.


Most GP’s will prescribe synthetic thyroid hormone for hypothyroid patients e.g. Eltroxin. This is mainly T4 and so if the body has difficult converting T4 to T3 for whatever reason, it makes dosing very difficult. If we look at the feedback loop above you might observe that there is another difficulty with replacing T4 in this way. As the synthetic hormone is consumed, the levels of T4 in the blood start to rise. The brain can detect these elevated levels and reduce its output of TSH. This is why those who are commenced on synthetic hormone therapy often need to increase the dose over time and will usually need to take thyroid hormone for life.

Most GPs only test T4 and TSH +/- Thyroid Antibodies. As we have seen, it is primarily T3 that exerts an effect on the cells of the body. So although T4 may be normal on your blood test, you may still be experiencing symptoms of hypothyroidism. This is because your body cannot convert T4 to T3. At Invigorate Clinic, we always tests T3 and reverseT3.

It is also important to remember that even very slight fluctuations in thyroid hormone can have profound effects on metabolism and energy. Standard tests are based on “normal” reference ranges but what is normal for one person, may not be “normal” for you!

Thus, hypothyroidism is frequently missed in standard tests.

In many cases, we also test urine thyroid hormones over a 24 hour period. This gives us a more representative insight into the fluctuations in your thyroid hormones throughout the day. Urine analysis of hormones also gives us an idea as to the amount of hormones your cells can actually use rather than just the amount traveling around in your blood.

A variety of factors may affect your thyroid function:

  •  Insufficient Iodine: (WARNING it is not advisable to supplement with Iodine without the supervision of your Functional Medicine Doctor)
  • Heavy Metal Toxicity: e.g Mercury, Cadmium
  • Fluoride: found in toothpaste and in the water supply in some areas
  • Dieting: e.g. severe calorie restriction
  • High Female Hormone Levels: e.g. high oestrogens
  • Certain medications
  • Environmental Pollutants
  • Pregnancy
  • Stress: too much cortisol interferes with the conversion of T3 to T4 (see more about Cortisol, Stress and Energy in Part 3)
  • Liver Dysfunction


Thus, a comprehensive Functional Medicine workup is recommended for all patients suffering from low thyroid function (and indeed low energy levels) in order to establish the cause of the dysfunction.


If you or someone you know suffers from low energy or low thyroid function, contact us today for a comprehensive work up.