Hypothyroidism vs Hyperthyroidism: Differences & Treatments

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Hypothyroidism and hyperthyroidism are both severe thyroid conditions, but they are essentially opposites from one another. Hypothyroidism describes an underactive thyroid, while hyperthyroidism describes an overactive thyroid.

About 1% of American adults experience hyperthyroidism, while approximately 5% of American adults experience hypothyroidism. More than half of thyroid disease patients may not know they have thyroid problems.

Below, we’ll take you through the similarities and differences between the two thyroid diseases.

If you’re looking for a fresh perspective on treating thyroid disorders, schedule a free phone consultation with PrimeHealth experts. We have years of experience treating and even reversing real-life cases of hypothyroidism and immune system disorders.


Hypothyroidism refers to an underactive thyroid. “Hypo” is the Greek stem for “under.”

An underactive thyroid can be caused by any of the following:

  • Thyroid gland, low production of thyroid hormones (T4/thyroxine and T3/triiodothyronine) — known as primary hypothyroidism
  • Pituitary gland not producing enough thyroid-stimulating hormone (TSH) — often known as secondary hypothyroidism
  • Hypothalamus not producing enough thyrotropin-releasing hormone (TRH) — sometimes known as tertiary hypothyroidism, but may also be called secondary hypothyroidism

Common symptoms of hypothyroidism include weight gain, fatigue, goiter, and sensitivity to cold. (Check out our article on losing weight with hypothyroidism.)

The most common trigger for hypothyroidism is the autoimmune disorder called Hashimoto’s disease, which can be caused by:

  • Hormone imbalance — If your hormone levels are not within a normal range (not just your thyroid hormone levels), Hashimoto’s thyroiditis can flare-up. Thyroid hormone replacement therapy may help solve thyroid hormone deficiencies, but won’t necessarily balance your other hormones.
  • InfectionsTick-borne infections (like Lyme disease) and viral infections (like Epstein-Barr) may lead to Hashimoto’s disease and, therefore, hypothyroidism.
  • Food sensitivities — Food allergens can trigger Hashimoto’s disease. For instance, celiac disease (a gluten allergy) has been linked to an increased risk of autoimmune diseases, such as Hashimoto’s.
  • Nutrient deficiency — Deficiencies in certain nutrients can trigger Hashimoto’s disease. The most common nutrient deficiency that leads to hypothyroidism is iodine deficiency.
  • Toxin exposure — Harmful toxins wreak havoc on your health, especially your thyroid. Heavy metal exposure, mold toxins, and exposure to chemicals like pesticides and other industrial chemicals can trigger Hashimoto’s thyroiditis.
  • Leaky gut — When the lining in your gut is chronically inflamed, the tight junction proteins in your intestinal wall may weaken and allow toxins, microbes, and food particles into the bloodstream. Called leaky gut syndrome, this is both a cause and symptom of Hashimoto’s. To learn from experts about leaky gut and take immediate action to optimize your gut health, join our online Prime Gut Course.


Hyperthyroidism is when an overactive thyroid gland produces too much thyroid hormone. This can increase your metabolism, leading to unintended weight loss, irregular heartbeat, anxiety, and sweating. “Hyper” is the Greek stem for “over.”

The most common cause for hyperthyroidism is the autoimmune disease called Graves’ disease, in which your own body’s antibodies over-stimulate your thyroid to produce more than enough thyroid hormone.

Common symptoms include weight loss, appetite loss, heart problems, and sensitivity to heat.

The most common treatment for hyperthyroidism is medications and radioactive iodine, but surgery may be necessary in severe cases.

A functional medicine approach is applicable and extremely beneficial to both hypothyroidism and hyperthyroidism patients. Take, for instance, this published case of remission of Grave’s Disease (autoimmune hyperthyroidism) using lifestyle changes alone. 

What is the difference between Hyperthyroidism and Hypothyroidism?

The difference between hyperthyroidism and hypothyroidism is whether the thyroid gland is overactive or underactive. “Hyper” means “over,” and “hypo” means “under.”

Hyperthyroidism can lead to weight loss and heat sensitivity. Hypothyroidism can lead to weight gain and cold sensitivity.

Untreated thyroid disorders can be dangerous and lead to heart disease, enlarged goiter, constant fatigue, and even death in severe cases.

Both thyroid disorders may be caused by autoimmune disorders. Graves’ disease can trigger hyperthyroidism, and Hashimoto’s disease can trigger hypothyroidism.

Do you gain weight with hypothyroidism or hyperthyroidism? You gain weight with hypothyroidism (underactive thyroid). You typically lose weight with hyperthyroidism (overactive thyroid).

Which is worse: hypothyroidism or hyperthyroidism?

Neither is worse than the other. Both can lead to death in the most severe cases. However, hypothyroidism is 5 times more common than hyperthyroidism.

In severe cases, hypothyroidism can lead to heart disease and myxedema coma, both of which can lead to death.

Hyperthyroidism may lead to heart problems, such as irregular heartbeat, high blood pressure, stroke, and cardiac arrest.

Common Causes of Hypothyroidism

  • Hashimoto’s thyroiditis
  • Iodine deficiency
  • Over-treatment of hyperthyroidism
  • Thyroid surgery
  • Radiation therapy
  • Pituitary disorder
  • Thyroid cancer
  • Pregnancy

Common Causes of Hyperthyroidism

  • Graves’ disease
  • Plummer’s disease
  • Over-treatment of hypothyroidism
  • Inflammation of the thyroid (thyroiditis)
  • Toxic adenoma
  • Toxic multinodular goiter

Hypothyroidism Symptoms

  • Fatigue
  • Sensitivity to cold
  • Low body temperature
  • Constipation
  • Weight gain
  • Muscle weakness
  • Muscle aches
  • Joint pain
  • Hoarseness
  • Dry skin
  • Thinning hair
  • Slow heart rate
  • Elevated cholesterol levels
  • Depression
  • Memory impairment
  • Goiter (enlarged thyroid gland)
  • Irregular menstrual periods
  • Myxedema coma

Symptoms of Hyperthyroidism

  • Fatigue
  • Sensitivity to heat
  • High body temperature
  • Unintentional weight loss
  • Increased appetite
  • Anxiety
  • Irritability
  • Tremors
  • Sweating
  • More frequent bowel movements
  • Muscle weakness
  • Sleep disruptions
  • Brittle hair
  • Goiter (enlarged thyroid gland)
  • Serious eye problems
  • Menstrual changes
  • Irregular heartbeat
  • Palpitations
  • Heart disease

Hypothyroidism Treatments

Check out our article on levothyroxine side effects to help you figure out if it’s right for you.

Hyperthyroidism Treatments

Outlook for Thyroid Disorder

According to the American Thyroid Association, there is no cure for hypothyroidism and other thyroid function problems. However, our healthcare experts disagree, based on personal experience with endocrine issues.

At PrimeHealth, we have worked with hundreds of patients dealing with thyroid disorders, especially hypothyroidism and Hashimoto’s thyroiditis. When conventional doctors say it’s incurable, we often find ways to treat and even reverse hypothyroidism permanently.

Sign up for a free phone consultation with us, and see how we can help you in your unique situation. We believe in a science-based mixture of conventional and integrative medicine, as well as an individualized approach to treatment options. No one-size-fits-all plans here.


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  4. Brogan, K., Marcelino, G., Pedro, C., & Siefert, A. (2019). Healing of Graves’ Disease Thorough Lifestyle Changes: A Case Report. Adv. Mind Body Med, 33, 4-11.
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