The thyroid is a butterfly-shaped gland located in the neck that weighs less than one ounce. It produces two hormones: triodothyronine (T3) and thyroxine (T4).

Thyroid hormones affect metabolism (the way the body uses energy), brain development, body temperature, muscle strength, skin tone, menstrual cycles, cholesterol levels, and weight gain. Simply put, without enough thyroid hormone, many of the body’s functions slow down or don’t function properly at all.

Hypothyroidism affects women more often than men

Hypothyroidism, or underactive thyroid, can affect both men and women; however, women are typically more prone to the condition. The primary underactive thyroid symptoms in women and men alike include: 

• Fatigue and lack of energy (especially in the morning)
• Memory loss
• Cold intolerance
• Joint and muscle pain
• Dry or itching skin
• Cracking nails
• Loss of hair
• Weight gain or difficulty losing weight (If you just cannot lose those extra pounds in spite of your best efforts at dieting and exercise, an underactive thyroid might in fact be the missing link!)
• Low sex drive
• Constipation
• High cholesterol levels
• Chronic infections
• Depression

The underactive thyroid symptoms in women only include:

• Heavy or irregular menstrual periods
• Severe PMS
• Fertility problems
• Endometriosis
• Ovarian cysts
• Excessive menopausal symptoms

Is a low functioning thyroid gland a contributing factor to your depression?

Thyroid hormones and depression are intricately connected. Here’s why:

• Christiane Northrup, MD, reports that T3 (the active thyroid hormone) “is actually a bona fide neurotransmitter that regulates the action of serotonin, norepinephrine, and GABA (gamma aminobutyric acid), an inhibitory neurotransmitter that is important for quelling anxiety.” She also states that “If you don’t have enough T3, or if its action is blocked, an entire cascade of neurotransmitter abnormalities may ensue and can lead to mood and energy changes, including depression.”[1]
• Dr. Barry Durant-Peatfield, in his book Your Thyroid and How to Keep It Healthy, states “Brain cells have more T3 receptors than any other tissues, which means that a proper uptake of thyroid hormone is essential for the brain cells to work properly.” He feels that up to one-half of depression cases are due to unrecognized hypothyroidism.

How to tell if you have low thyroid function

To determine if you have an underactive thyroid, follow these three steps:

Step 1. Determine if you have three of more of the common underactive thyroid symptoms in women or men. The more your symptoms match the typical profile of low thyroid function, the greater the likelihood you have hypothyroidism. If you do, in fact, have three or more symptoms above, then conduct the next test:

Step 2. Conduct the Barnes Basal Body Temperature test. Since your thyroid hormone regulates metabolism in the body, your metabolism rate is a good measure of thyroid hormone function. In fact, according to the results of a 2005 study published in the European Journal of Clinical Nutrition, the basal metabolic rate is a much more reliable indicator of thyroid hormone deficiency than blood testing. A doctor named Broda Barnes discovered a quick and easy way to test metabolism: just take your resting body temperature. If your basal body temperature is lower than 97.8 degrees, you should be highly suspicious that thyroid function is a possible cause.

Step 3. Perform laboratory testing. If the first two tests above indicate a possible thyroid disorder, it’s time to get your doctor involved with standard laboratory testing:

Why not just skip the first two steps in this thyroid function test and go directly to the lab tests? Frankly, the standard TSH (thyroid-stimulating hormone) lab test is often inadequate in detecting what is called “suboptimal thyroid function”. Many people suffer the symptoms of low thyroid but have lab results that put them in the “normal” reference range and thus are declared to have a healthy thyroid function. However, many integrative physicians have found that these patients often benefit greatly and recover completely from many of their chronic symptoms by either starting a thyroid hormone replacement regimen or by addressing the root causes of an under-functioning thyroid – all this in spite of the fact that their lab results indicate no need for the hormone. This is the condition called Subclinical Hypothyroidism which affects thousands of people and is one of the most under diagnosed disorders. So the bottom line is that “suboptimal thyroid functioning” is surprisingly common and could be affecting your mood and causing depressive symptoms.

Here are some of the serum lab tests recommended to adequately measure thyroid function for someone who is symptomatic and has low basal temperature:

• TSH — the high-sensitivity version. The ideal level for TSH is between 1 and 2.0 mIU/L (milli-international units per liter) and may need to be adjusted to slightly less than 1.0 to give adequate relief to hypothyroidism symptoms in some people.
• Free T4 and Free T3. The normal level of free T4 is between 0.9 and 1.8 ng/dl (nanograms per deciliter). T3 should be between 240 and 450 pg/dl (picograms per deciliter). Remember that conventional physicians often do not perform the free T3 test. However, it is a very important way of assessing overall thyroid function.
• Thyroid antibodies including thyroid peroxidase antibodies and anti-thyroglobulin antibodies. This test helps determine if there is an autoimmune disease of the thyroid such as Hashimoto’s thyroiditis. For more difficult cases TRH can be measured (thyroid releasing hormone) using the TRH stimulation test. TRH helps identify hypothyroidism that’s caused by inadequacy of the pituitary gland.

How to Treat Low Thyroid Function

Don’t let low thyroid function zap your energy and cause your depressive symptoms to thrive.  There are several approaches available to treat low thyroid function.

• Using synthetic (Synthroid) versus natural (Armour thyroid) hormone replacement therapy
• Optimize adrenal function
• Optimize the body’s iodine level
• Increase consumption of the amino acid, tyrosine
• Take selenium and zinc
• Detox mercury
• Correct gluten sensitivity problems
• Get the best water filtration systems for your home
• Take a thyroid glandular extract
• Test for a vitamin D deficiency
• Utilize omega-3 fatty acid
• Begin exercising.

If you suffer from suboptimal thyroid function, please tell us about your experience in the comments section below.

[1] Thyroid Disease, Christiane Northrup, M.D.

Originally published in 2013.