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Thyroid Health-Hypothyroidism (Underactive Thyroid) vs. Hyperthyroidism (Overactive Thyroid)

You & Your Thyroid

Self Breast Exam
You & Your Thyroid Gland

The human body is made up of 11 major systems, all of which are influenced and regulated by hormones produced by the endocrine system. Hormones are chemical messengers that control bodily functions, which range from basic needs – such as hunger – to major functions like metabolism and reproduction. When any of these hormones fall out of balance, it can lead to serious issues.

What is the Thyroid Gland? The thyroid gland is a small, butterfly-shaped organ located at the base of the neck and it is an integral part of the endocrine system. Though it measures only two inches long, this gland is responsible for producing and releasing hormones that control metabolism and regulate essential bodily functions including:

  • Heart rate

  • Respiration

  • Bodyweight

  • Muscle mass

  • Body temperature

  • Menstruation

  • Cholesterol levels

The thyroid gland produces both the inactive hormone Thyroxine (T4) and the active hormone Triiodothyronine (T3), in lower amounts; together, they are referred to as thyroid hormones. These hormones, along with hormones produced in the hypothalamus and pituitary gland, make up a feedback loop known as the hypothalamic-pituitary-thyroid axis. How Do Thyroid Hormones Work? To maintain properly balanced in T3 and T4 levels, the thyroid works in conjunction with the hypothalamus in the brain and the pituitary gland. When thyroid hormone levels start to drop, the hypothalamus produces Thyrotropin-releasing hormone (TRH). This hormone triggers the pituitary gland to increase production of thyroid stimulating hormone (TSH), which signals the thyroid gland to produce more thyroid hormone.

The hormones produced in the thyroid gland have a direct influence on metabolism and the way the body produces and utilizes energy. Both T3 and T4 play a role in determining how quickly the digestive system breaks down food and absorbs nutrients. They also regulate heart rate, which determines how quickly those nutrients are spread throughout the body via the bloodstream. When thyroid hormone levels are low (hypothyroidism), heart rate slows and digestive problems like constipation and weight gain may develop. When they are too high (hyperthyroidism), heart rate may become too rapid and diarrhea and weight loss are likely to occur. Underactive vs. Overactive Thyroid Also known as hypothyroidism, underactive thyroid is often caused by inflammation of the thyroid gland. Thyroid inflammation can be triggered by a number of things, but the underlying issue is that the inflammation damages or kills thyroid cells, inhibiting the gland’s ability to produce sufficient amounts of thyroid hormone. When production of thyroid hormone slows down, so do essential bodily processes like heart rate, metabolism, and digestion. It can also lead to issues with mood and libido.

The most common cause of hypothyroidism is an autoimmune disease called Hashimoto's thyroiditis. On the surface, this condition causes the immune system to mistakenly attack healthy thyroid cells. Delving deeper into the root of the issue, however, the resulting inflammation and autoimmune activity is often a sign of other problems, such as exposure to environmental toxins, allergens, and infections. Poor diet and chronic stress are also common culprits.

Other causes of hypothyroidism are commonly related to surgical and medical treatments. For example, conditions like Graves’ disease and thyroid cancer may necessitate the surgical removal of part or all of the thyroid which can significantly impact thyroid hormone production. Certain medications have been known to inhibit thyroid hormone production, and dietary insufficiencies of iodine are common. Hypothyroidism can also be a congenital condition.

On the opposite end of the spectrum, hyperthyroidism – or overactive thyroid – occurs when the thyroid produces too much thyroxine which causes bodily processes such as metabolism, heart rate, respiration, and nerve activity to speed up. Hyperthyroidism is often secondary to another condition, such as Graves’ disease, Plummer disease, or toxic adenoma. Inflammation of the thyroid gland can also be a causative factor, triggered by exposure to a virus, toxin, medication, or dietary deficit.

Graves’ disease – a type of autoimmune disorder – is the primary cause for 70% of hyperthyroidism cases. This condition has a genetic link and tends to affect women more than men. Plummer disease, also known as toxic multinodular goiter, is characterized by nodules or lumps in the thyroid gland that affect hormone production. Toxic adenoma is a toxic thyroid nodule that grows on the thyroid, causing it to become enlarged and increasing hormone production. What Are the Signs and Symptoms? Because thyroid hormones play a role in regulating many bodily functions, underactive and overactive thyroid can trigger a variety of symptoms. Signs of Hypothyroidism When the thyroid produces insufficient amounts of thyroid hormone, bodily processes may slow down, which can lead to any of the following:

  • Fatigue

  • Weight gain

  • Difficulty losing weight

  • Coarse, dry hair

  • Dry skin

  • Weakness

  • Hair loss

  • Low body temperature

  • Muscle cramps

  • Body aches

  • Irritability

  • Low mood or depression

  • Constipation

  • Impaired memory

  • Decreased libido

  • Abnormal menstruation

These symptoms may present in any combination, though it is also possible for patients with hypothyroidism to display no symptoms at all, or symptoms too subtle to notice. Though these symptoms may seem mild, they will progress if left untreated. Untreated hypothyroidism can lead to dangerous complications such as severe depression, heart failure, coma, or death. Fortunately, the condition is easy to diagnose with a simple blood test, and it can be managed with lifestyle changes and medical treatments. Signs of Hyperthyroidism Overactive thyroid causes certain bodily processes to speed up, which can trigger issues with weight loss, heart rate, metabolism, and nerve activity. Some of the most common symptoms of hyperthyroidism include the following:

  • Unexplained weight loss

  • Rapid heart rate

  • Irregular heartbeat, arrhythmia

  • Nervousness or anxiety

  • Increased appetite

  • Irritability

  • Changes in menstruation

  • Increased sensitivity to heat

  • Changes in digestion

  • Fatigue

  • Muscle weakness

  • Enlarged thyroid, goiter

  • Thin, pale skin

  • Fine, brittle hair

  • Trouble sleeping

  • Tremors

Chronically elevated thyroid hormones can speed heart rate and contribute to a heart rhythm disorder – known as atrial fibrillation – in which the heart is unable to pump blood sufficient to meet the body’s needs. Excess thyroid hormone in the blood can also interfere with the absorption of calcium, which can lead to osteoporosis or brittle bones. Graves’ disease, one of the most common causes of hyperthyroidism, has been known to cause eye and skin problems. It is also possible for high thyroid hormone levels to trigger a thyrotoxic crisis in which symptoms suddenly intensify, causing fever, rapid heart rate, and delirium. Common Treatment Options Because the symptoms of hypothyroidism and hyperthyroidism are linked to the over- or under-production of thyroid hormone, correcting thyroid hormone levels is the key to effective treatment.

To correct hormone levels in patients with hypothyroidism, levothyroxine (Synthroid) – a form of synthetic T4 – is the treatment with which people are most familiar; however, a combination of T4 and T3 medications is often far more effective than T4 alone because the T4 hormone is less physiologically active than T3 and needs to be converted to T3 by the body.

Specifically, many patients find success with some combination of a T4 formulation (Synthroid; Levoxyl; Tirosint) and T3 formulation (Cytomel; extended-release Liothyronine). Natural desiccated thyroid is the most physiologic way to replace thyroid hormone deficiency because it is bioidentical to human thyroid and contains all five thyroid hormones (T1-T4 and calcitonin). Examples include Nature Thyroid, WP Thyroid, NP Thyroid, and Armour Thyroid.

Treatment for hyperthyroidism is aimed at suppressing the production of thyroid hormones. The ideal treatment plan is determined by a combination of the patient’s age, health status, and the severity of the condition. Common treatment options include antithyroid drugs, radioactive iodine therapy, and surgical removal of the thyroid gland.

Antithyroid drugs, also known as antithyroid agents, control thyroid activity to reduce hormone production without causing any permanent damage to the thyroid gland. Long-term use of these drugs frequently results in prolonged remission, but there is a risk for side effects such as skin rashes, fever, joint pain, and reduced resistance to infection. Radioactive iodine therapy is designed to damage or destroy the cells in the thyroid that produce thyroid hormone. Thyroid cells require iodine to produce hormones, so this treatment ensures that those cells will absorb the radioactive iodine. The radioactive agent enters the blood stream quickly and slowly destroys the cells that absorb it.

For both hypothyroidism and hyperthyroidism, low-dose naltrexone is sometimes recommended as a complement to the treatments outlined above. Naltrexone is an FDA-approved medication typically prescribed for opioid addiction; however, in low doses, it has been found to boost the immune system and improve autoimmune conditions like Hashimoto’s.

Though medical treatments exist to mitigate symptoms of overactive or underactive thyroid, the best long-term solution is to address the underlying issues that triggered the problem in the first place. Exposure to toxins, allergens, infections, and stress can cause widespread inflammation throughout the body, including in the thyroid gland. Limiting exposure to these things is essential.

Additionally, making healthy changes to diet and lifestyle will benefit long-term management of the disease. A balanced diet with sufficient intake of iodine will support thyroid health, while controlled calorie intake will help prevent weight loss or weight gain. Supplementation with calcium and vitamins may also help counteract some of the symptoms of thyroid issues.

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