The thyroid gland makes three hormones that are responsible for the function of nearly every cell in the body, so it’s no surprise that a properly working thyroid is essential to many aspects of our health. As we age, thyroid hormone imbalances become more common, and cause conditions ranging from weight gain to depression and fatigue. If you believe you might have a thyroid imbalance, Modern Age can help you test for these biomarkers.

What biomarkers measure thyroid health?

Thyroid stimulating hormone

The thyroid is controlled by the pituitary gland. The pituitary gland is found in your brain and is responsible for making thyroid stimulating hormone (TSH). TSH is not a thyroid hormone, although it works alongside them; TSH tells your thyroid how much thyroid hormone it needs to make to keep the functions the thyroid controls balanced. Normal TSH levels for a non-pregnant adult age 21 and older are 0.27-4.2 uIU/mL

If you test for low amounts of TSH, it could indicate that you have an overactive thyroid, and the TSH is compensating by signaling to the thyroid to produce less hormones. Symptoms of an overactive thyroid include weight loss, irregular heartbeat, anxiety, insomnia, shaky hands, sweating, and frequent bowel movements. Hypothyroidism, which can be detected by high amounts of TSH, can cause weight gain, cold sensitivity, dry skin, thinning hair, and irregular menstrual periods, among other symptoms. 

Free T4

T4, otherwise known as thyroxine and tetraiodothyronine, is one of the main hormones produced by the thyroid gland and released into the bloodstream. It plays an important role in muscle function, digestion, and bone health. 

The two types of T4, free and bound, are named for how they enter your bloodstream. Free T4 moves freely through the bloodstream and can enter cells directly. Bound T4 attaches to your body’s proteins and does not enter cells directly. Additionally, your body’s livers and kidneys convert much of T4 into T3, another active thyroid hormone that impacts essential bodily functions.

While some doctors test for both Free and Bound T4 levels, a Free T4 test offers a more accurate assessment of thyroid health, alongside tests for TSH and Free T3. A normal Free T4 range for a non-pregnant adult is between 0.8–1.8 (ng/dl).

Free T3

T3, like T4, is created by your body’s thyroid gland. But unlike T4, much of T3 in the bloodstream (approximately 80%) is created through conversion of T4 in the liver and kidneys. The majority of T3 is Bound T3 which, as described above, is attached to proteins as it circulates in the bloodstream. TSH regulates the body’s levels of bound and free TS3 to keep the body’s key functions in check.

A normal level of T3 for non-pregnant adults is 130 to 450 picograms per deciliter (pg/dL), or 2.0 to 7.0 picomoles per liter (pmol/L).

Test your thyroid health

Thyroid dysfunction becomes more common as you age, and can be the cause of a variety of unexpected or seemingly unexplainable symptoms. Modern Age’s Aging Wellness Assessment can help. Our clinically created series of tests measure 55 key biomarkers associated with aging, including TSH, free T3, and free T4. You’ll receive a comprehensive report, and work 1:1 with a licensed clinician to understand your results and create a plan to address your symptoms. Common treatments for thyroid disorders include prescription medication, but over the counter options are available.