Why Do I Have Low T3 Levels?

In my last article, I mentioned that low T3 levels can cause you to feel symptoms, like hair loss, tiredness, weight gain, moody feelings, and loss of sex drive. These are hypothyroid symptoms that you can experience even if blood tests, like TSH, are normal. So, what causes low T3?

Sometimes, the T3 levels in your blood might be OK, but your tissue T3 is low. This is when you can get symptoms that your medical doctor can’t figure out. T3 in the tissues is made from T4, but many things can interfere with this process. If you have a deficiency in certain nutrients, like iodine, selenium, and protein, your thyroid can have trouble making enough T4 that can be later converted into T3 in the tissues. But it’s often the things that interfere with the conversion of T4 into T3 that cause the most trouble.

Stress – the main reason for low T3

Stress is the most common factor that can slow down T4 to T3 conversion. A class of hormones, called glucocorticoids, are made by your adrenal glands. They are some of the strongest blockers of T4 to T3 conversion. When you’re stressed out, your adrenal glands produce more of a glucocorticoid called cortisol. The cortisol stops the T3 from being made in your tissues.

Therefore, the less T3 you have in your tissues, the slower your metabolism is and the more symptoms of hypothyroidism you will get. On top of that, the less T3 you can make, the more reverse-T3 that your body makes. Reverse-T3 (rT3) slows down your metabolism even more. This is the metabolic disaster that I mentioned in a previous article. The symptom picture that follows it is sometimes called Wilson’s Temperature Syndrome or WTS.

How do I know if I have low levels of tissue T3?

The blood ratio of T3 to rT3 gives a good idea of the tissue levels of T3. However, body temperature is the measurement that most closely matches the symptoms that accompany low tissue T3.

When your thyroid system is functioning perfectly, your average body temperature will be 98.6°F or 37°C. If your average daily temperature is much lower than that, you will start to feel the symptoms I mentioned earlier.

The best way to see if your thyroid system is working is by measuring your oral temperature three times a day at three-hour intervals, starting at three hours after waking. If, after a few weeks of measurement, your average temperature is low, you know that you need to see someone that can address your thyroid issue without relying on unreliable blood tests.

I hope, after this series, you have a better understanding of what your thyroid does and how important it is to your health. Remember, your symptoms just might be related to your thyroid, even if your doctor says otherwise!

Until next time, this is Dr. Pat Nardini, ND, putting “Your Wellness First!”