The importance of thyroid testing:

It’s not just for women

Published May 18, 2023. Last updated January 6, 2026

The thyroid gland is a small but powerful part of your endocrine system. Its main job is to produce certain hormones, which are released into your bloodstream and carried to every tissue in your body. These hormones help regulate your metabolism, or how well your body converts food into energy.¹

Because every cell in your body needs energy to function, thyroid hormones can affect everything your body does. They help regulate heart rate, blood pressure, breathing, digestion, body temperature, cholesterol levels, weight, mood, memory, and muscle function. They also help support fertility and keep skin, hair, nails, and bones healthy. In women, thyroid hormones help manage the menstrual cycle.²

Thyroid disorders can affect men and women of all ages. They can happen when the thyroid produces too much (hyperthyroidism) or too little (hypothyroidism) hormone. Testing is important, especially if thyroid conditions run in your family, since undiagnosed thyroid issues can lead to infertility, sexual dysfunction, osteoporosis, and heart disease.²

Common thyroid conditions and disorders

Hypothyroidism

Hypothyroidism, or an underactive thyroid, is when your body doesn’t make enough thyroid hormone. It can cause symptoms like fatigue, brain fog, forgetfulness, constipation, and weight gain.³

Men with an underactive thyroid may also experience sexual dysfunction, low testosterone, and infertility.⁴

Hypothyroidism can affect women at any age, but it most often develops between ages 30 and 50. It can disrupt the menstrual cycle, though other symptoms may not appear until the condition becomes more advanced.⁵

Teens with hypothyroidism may experience slowed growth or delayed puberty.

Causes of hypothyroidism in both men and women include autoimmune disease (Hashimoto thyroiditis), inflammation of the thyroid gland, certain medicines, too much or too little iodine, goiter (enlarged thyroid gland), and other health conditions affecting thyroid function.²

Hyperthyroidism

Hyperthyroidism, or an overactive thyroid, is when your body makes too much thyroid hormone. It can cause symptoms like fatigue, anxiety, heat sensitivity, muscle weakness, and weight loss.³

Men with an overactive thyroid may also experience low sex drive, difficulties with sexual function, muscle stiffness or weakness, and dry or thinning hair.⁴

Causes of hyperthyroidism in both men and women include autoimmune disease (Graves disease), inflammation of the thyroid gland, certain medicines, too much iodine, and medical conditions like thyroid nodules (small lumps or growths) or cancer.²

The role of iodine in thyroid health

Iodine is a trace mineral that’s essential for making 2 main thyroid hormones (T3 and T4). The thyroid gland can't produce the proper amount of hormones without enough iodine.

When iodine levels are too low, the thyroid may enlarge in an effort to capture more iodine from the bloodstream, leading to a goiter and symptoms of hypothyroidism. However, when iodine levels are too high, it can interfere with thyroid function and may trigger hyperthyroidism or thyroid inflammation in some people.

Because our bodies don't produce iodine, we must get it from food, iodized salt, or supplements. Iodine is naturally found in animal proteins, fish (cod, tuna), shellfish (shrimp, oysters), dairy products (milk, yogurt, cheese), seaweed (dulse, kelp, nori), eggs, and iodized table salt.

Nutrients impacted by thyroid disorders

Thyroid health and nutrition go hand in hand. Thyroid disorders can make it harder for your body to get the nutrients it needs. Your thyroid relies on 4 important nutrients to function properly: iodine, iron, selenium, and vitamin D. These nutrients help support and protect overall thyroid health.

When these nutrients are lacking, thyroid hormone production can be disrupted, making thyroid symptoms worse. But there’s a twist: thyroid disorders can also cause nutrient deficiencies. This relationship creates a cycle where thyroid disorders and nutrient deficiencies feed into—and potentially worsen—each other. Understanding this connection and correcting any nutrient deficiencies is essential for supporting thyroid health and overall well-being.

The Quest Thyroid TSH Function Test checks your levels of thyroid stimulating hormone (TSH)—produced in the pituitary gland—and can help confirm if your thyroid is working properly. Based on your hormone level, further testing may be required to help identify any thyroid disorders.

This test is also part of larger test panels on questhealth.com, such as:

• Basic Health Profile – Women's
• Comprehensive Health Profile – Women's
• Elite Health Profile
• Fatigue Test Panel
• Fitness Profile – Elite Test
• Post-COVID-19 Basic Test Panel
• Post-COVID-19 Expanded Test Panel
• Pre-Pregnancy Test Panel
• Menopause & Perimenopause Assessment Test Panel
• Post Menopause Assessment Test Panel
• Women's Hormone Test Panel – Basic
• Women's Hormone Test Panel – Extended

If you’ve already been diagnosed with a thyroid disorder, Quest offers 2 Thyroid Disorder Monitoring tests to measure key hormones in thyroid function while you’re undergoing treatment.