Have you noticed lately that your energy levels aren't as high as they used to be? Maybe your temperature has been fluctuating a lot, and most of the time you feel overly cold, even in warm rooms. Or possibly your weight has been increasing, even though you are exercising and watching what you eat. These all can be signs your thyroid is in stress and if you go to your doctor, they will probably send you out for some testing. Usually the initial test is to check on your thyroid stimulating hormone (TSH) levels. If this test is elevated, it could mean the thyroid is underactive and isn't able to keep up with the needs of the body. If the level is low, it could mean the thyroid is overactive. Usually the next test will be for T4 and Free T4, then determine what medication you may need from those tests alone. But is this enough testing to get a full picture of how the thyroid is truly functioning?
I know I know, there are a lot of T abbreviations being thrown around, so what the heck do all those mean? TSH is the thyroid stimulating hormone. TSH is released from the pituitary gland and goes to the thyroid to tell it how much T4 to produce. T4 is stored within the body and when your body needs thyroid hormones to activate, T4 converts to T3, which is the active hormone. This conversion happens mainly in the liver; the next area it converts is in your gut. This is really important from a functional standpoint because if your liver is congested and not functioning properly, or if your gut is inflamed, this conversion process will be compromised. When the liver and gut are compromised, or if you have a lot of stress in your life/body, you will have an increase in cortisol output from your adrenal glands, which the cortisol will help produce an inactive form of T3 called reverse T3 (rT3). This rT3 binds to the same receptor sites on your cells as regular T3, but your cells can't utilize the rT3, so you run into an issue of the cells becoming resistant to T3 (T3 is what stimulates your metabolism!). So when we only test for TSH and T4, we don't get to see if the conversions are actually happening the way that they should!
You are experiencing all the symptoms of a hypothyroid (weight gain, hair loss, feeling cold, fatigue). You have been taking T4 medication, but your doctor wants to test your TSH and T4 levels again to double check that everything is working properly. The tests come back, and all your levels are within normal range. The doctor releases you and says that you can't possibly have any issues with your thyroid. You go on with your life, still feeling cold, still gaining weight, and not understanding what is going on. Interestingly enough, rT3 will give you all the symptoms of a hypothyroid, even if your TSH and T4 are in normal ranges. That is why additional testing must be done!
Typically when I see these cases come through, I will run an rT3 panel to double check with my suspicions. At the same time, I will use a Hair Tissue Mineral Analysis to see where the mineral levels are that are needed for thyroid hormone conversion. Sometimes I will even test the Free T3 levels to check ratios with the rT3 for a more accurate look at what exactly is going on. There are labs available where you can get these tests done yourself, you can ask your doctor to order these tests, or I will order these tests for my clients. Understanding blood tests can be challenging for a lot of practitioners, and if they don't take the time to look at the bigger picture of your body, they can be missing some very key pieces to your health!