If you feel cold and sluggish all the time, easily gain weight, and have frequent muscle pains and cramps, the reason for it might be hypothyroidism. Hypothyroidism or an underactive thyroid occurs in about 5% of people worldwide, while it is estimated that a further 5% of the population live with undiagnosed hypothyroidism.

Our guide will take a look at everything you need to know about this common condition, how to detect and diagnose it, what its main symptoms and complications are, and how it can be treated.

To help you on your health journey, you can also join Carecircle.org for free. Our international community of health advocates, scientists, and fellow patients is there to provide you with advice, hope, and support while you deal with your hypothyroidism or other medical conditions.

What is hypothyroidism?

Hypothyroidism or an underactive thyroid occurs when the thyroid gland, located at the front of your throat, produces insufficient amounts of thyroid hormone. Thyroid hormones play a big part in regulating the body’s metabolism, or simpler: it controls how the body uses energy. A lack of the hormone can therefore result in a number of symptoms, ranging from tiredness, cold sensitivity and constipation to weight gain, dry skin, and a slow heart rate.

Types of hypothyroidism

There are three types of hypothyroidism: primary, secondary, and tertiary.

1. Primary hypothyroidism results from physical damage to the thyroid gland, which causes an inability to produce (enough) thyroid hormone. Primary hypothyroidism is the most common form of hypothyroidism.
2. Secondary hypothyroidism is caused by an underactive pituitary gland – a gland in your brain –, which, in turn, causes an underactive thyroid. This type of hypothyroidism is very rare.
3. Lastly, tertiary hypothyroidism results from an issue in the hypothalamus, a part of the brain that is also responsible for regulating certain metabolic processes. If the hypothalamus releases too little Thyroid Releasing Hormone (THR), Thyroid-stimulating Hormone (THS) levels in the body decrease and cause the thyroid to produce insufficient amounts of thyroid hormone. Tertiary hypothyroidism is the least common form of hypothyroidism.

What causes an underactive thyroid?

Hypothyroidism, especially primary hypothyroidism, can result from various causes, such as injury to the thyroid, radiation, medication, or autoimmune disease. Let’s take a look at the most common causes:

• Autoimmune disease: One of the leading causes of hypothyroidism is autoimmune disorders, most commonly Hashimoto-Thyreoiditis, which causes chronic inflammation of the thyroid and leads to its inability to produce sufficient thyroid hormone. Other autoimmune disorders may affect the pituitary gland and therefore cause secondary hypothyroidism.
• Radiation therapy: Radiation therapy applied to the neck, as used to treat certain types of cancer, can cause permanent damage to the thyroid and its ability to function.
• Medication: Certain medications, such as some heart and cancer meds, or anti-depressants, can also cause a decreased production of thyroid hormones in the thyroid gland.
• Injury/trauma: If the thyroid is injured and/or partly removed for medical reasons, fewer thyroid hormones will be produced, leading to hypothyroidism.
• Diet: In order to function properly, the thyroid needs iodine. Although rare in the Western world, globally an estimated 2 billion people suffer from iodine deficiency, which may cause hypothyroidism.
• Hyperthyroidism/thyroid cancer treatment: If hyperthyroidism, an overactive thyroid, is overtreated, it can lead to the opposite condition, an underactive thyroid. Equally, if thyroid cancer is treated with radioactive iodine to destroy the affected thyroid matter and too much of it is affected, hypothyroidism may result.
• Congenital disorder: Sometimes, children are born with an underdeveloped or malfunctioning thyroid gland that lacks the ability to produce enough thyroid hormone. In these cases, hypothyroidism is present and needs to be treated from birth.
• Giving birth/postpartum thyroiditis: For reasons not quite known to modern science, women sometimes develop an inflammation of the thyroid after giving birth – a condition known as postpartum thyroiditis –, which can temporarily lead to hypothyroidism.
• Brain cancer/tumours/trauma: In rare cases, tumours in or trauma to the brain may affect the hypothalamus or pituitary gland and lead to secondary or tertiary hypothyroidism.

Other common risk factors for hypothyroidism are:

• sex: women are affected more often than men
• age: most cases of hypothyroidism occur after age 60
• prior thyroid issues or surgery
• existing autoimmune disorders
• a family history of thyroid or autoimmune disease
• chromosomal abnormalities, such as Down or Turner’s syndrome

No matter which medical condition you are dealing with, it’s easier to do so with the help and support of an open, embracing community. By joining carecirle.org you’ll gain access to a large, worldwide network of fellow patients, scientists, and health advocates to share the burden. Sign up now, it’s free!

What are the symptoms of an underactive thyroid?

Most symptoms of an underactive thyroid are related to the resulting inability of the body to efficiently use its energy. They are generally the same for males and females, although sexually related symptoms vary.

The most common symptoms of hypothyroidism are:

• persistent tiredness/exhaustion
• frequently feeling cold/a general sensitivity to cold
• weight gain
• feeling down/depression
• muscle aches, weakness, and/or cramps
• confusion or trouble concentrating
• constipation
• dry and/or scaly skin
• brittle hair and nails
• a decreased sex drive, pain during sex (women), or erectile dysfunction/ejaculation issues (men)
• tingling, numbness and/or pain in the hand and fingers (carpal tunnel syndrome)
• irregular and/or heavy periods

How to diagnose hypothyroidism?

The only way to diagnose hypothyroidism is by means of a blood test that will determine your TSH and thyroid hormone levels. The first test will typically look at your TSH levels. If they aren’t within the normal range, further tests for your specific T3 and T4 levels, the two main thyroid hormones, will be conducted.

What to do if you have hypothyroidism?

Hypothyroidism can be temporary, for example if it occurs after giving birth, or permanent, for example if your thyroid has been partly removed. In either case, swift treatment is crucial as untreated hypothyroidism may lead to an array of complications, ranging from a visibly enlarged thyroid (goitre) to issues during pregnancy, heart problems, and a potentially life-threatening condition named myxoedema coma. With proper treatment, hypothyroidism usually has very little impact on a patient’s overall quality of life.

Would you like to talk to other people affected by hypothyroidism? Our friendly, global Carecircle.org community is the perfect place to find help, hope, and control – and you can join it right away for free!

How can an underactive thyroid be treated?

Hypothyroidism or an underactive thyroid is commonly easily treatable by taking daily hormone supplements. It replaces the thyroid hormones the thyroid gland would otherwise produce itself. The effects may set in rather quickly or take several months to do so. The dose will commonly be set low in the beginning and then gradually increased until the desired hormone levels are achieved. In light cases of hypothyroidism, treatment may not be necessary.

Underactive Thyroid diet

In most cases of hypothyroidism, diet alone won’t be enough to get thyroid levels back to normal, it can, however, support other therapies and help in alleviating symptoms, such as weight gain.

A healthy, balanced low-fat diet, with plenty of fruits, vegetables, fish, lean meat, dairy, and whole grains, in combination with regular exercise can help you in countering weight gain and retaining more energy.

Iodine deficiency is one possible cause of hypothyroidism. However, if you’re eating normal amounts of salt and salty foods, having an iodine deficiency is very unlikely.

Hypothyroidism FAQs

Looking for quick answers to your most pressing questions about hypothyroidism? Have a look at our underactive thyroid FAQ!

What is an underactive thyroid?

Hypothyroidism or an underactive thyroid is a condition that occurs when the thyroid gland produces insufficient amounts of thyroid hormone.

What does the thyroid do?

A healthy thyroid produces thyroid hormones, most importantly T3 and T4. These hormones play a crucial part in regulating the body’s metabolism.

Is Hypothyroidism an autoimmune disease?

Hypothyroidism has several causes, some of which are related to autoimmune disease such as Hashimoto’s. However, not all forms of hypothyroidism result from autoimmune disease.

How to lose weight with an underactive thyroid?

By undergoing appropriate treatment, consuming a healthy, balanced diet, and getting plenty of exercise it is possible to lose weight despite the tendency to gain weight with hypothyroidism.

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Hypothyroidism Resources

• https://www.thyroid.org/hypothyroidism/
• https://www.nhs.uk/conditions/underactive-thyroid-hypothyroidism/
• https://www.niddk.nih.gov/health-information/endocrine-diseases/hypothyroidism

While hypothyroidism or an underactive thyroid is a rather common condition, may be uncurable, and can cause serious complications if untreated for prolonged periods, the prospect is generally very good. Ongoing treatment by means of daily hormone supplements allow for patients to live a live life largely unaffected by the condition. If you suspect you might have hypothyroidism, be sure to consult your doctor as soon as possible.

Guide Sources

National Library of Medicin/PubMed Central

• National Library of Medicine/PubMed Central: “Central Hypothyroidism”
• National Library of Medicine/PubMed Central: “Drugs that suppress TSH or cause hypothyroidism”
• National Library of Medicine/PubMed Central: “Iodine Deficiency, Still A Global Problem?”
• ScienceDirect – Hypothyroidism
• Cancer Therapy Advisor