Hypothyroidism

What is hypothyroidism?

Hypothyroidism means that your thyroid gland, a small butterfly-shaped gland in your neck, is producing too little of two important hormones: thyroxine (T4) and triiodothyronine (T3). These hormones influence nearly every organ in your body - they regulate how your cells use energy, how warm you feel, how your heart beats, and how your brain functions.

When your thyroid is underactive, your body’s metabolism slows down. This is sometimes called low metabolism or thyroid underfunction. Thyroid imbalance can also occur in the opposite direction. In hyperthyroidism, the gland produces too much hormone, speeding up the body’s processes instead, most commonly due to an autoimmune condition called Graves’ disease.

Because the change happens gradually, hypothyroidism can go unnoticed for months or even years. What feels like normal tiredness or stress may, in fact, be a sign that your thyroid hormone levels are lower than they should be.

Symptoms of hypothyroidism

The symptoms of low thyroid function can vary a lot from person to person. Some notice only mild tiredness, while others experience several overlapping signs that affect both body and mind.

Common symptoms include:

• Persistent tiredness or low energy

• Unexplained weight gain or difficulty losing weight

• Feeling unusually cold

• Dry skin, brittle nails or hair loss

• Puffiness in the face or around the eyes

• Sluggish digestion or constipation

• Slower heart rate

• Feeling down, irritable, or mentally foggy

In more advanced or long-term cases, people may also notice:

• Muscle stiffness or pain

• Swelling in the hands and feet

• Hoarseness

• Menstrual irregularities or fertility challenges

• Elevated cholesterol

• Pale or slightly yellowish skin tone

Some people may also notice fullness in the neck if the thyroid becomes enlarged or develops a thyroid nodule. Structural changes in the gland do not always affect hormone levels, but they are worth evaluating together with blood tests.

What causes hypothyroidism?

Hypothyroidism results from conditions that reduce the thyroid's ability to produce hormones. Contributing causes include:

• Hashimoto's thyroiditis: the most common cause in Sweden and other iodine-sufficient countries; an autoimmune condition in which the immune system gradually destroys thyroid tissue.

• Previous thyroid surgery or radioiodine treatment: removal or ablation of thyroid tissue reduces hormone production.

• Medications: lithium, amiodarone, and some other drugs interfere with thyroid hormone production.

• Pituitary dysfunction: rarely, insufficient TSH production from the pituitary causes secondary hypothyroidism.

• Iodine deficiency: a leading global cause, though rare in Sweden where iodine is added to table salt.

• Postpartum thyroiditis: temporary thyroid inflammation after pregnancy that can cause transient hypothyroidism.

• Genetic factors: family history of thyroid disease significantly increases individual risk.

In rare cases, congenital hypothyroidism can occur at birth, a condition that is screened for in all newborns through the PKU test.

How is hypothyroidism detected?

Hypothyroidism is one of the most straightforward conditions to detect, a blood test measuring TSH is the primary and definitive screening tool.

• TSH: The primary screening marker; elevated levels are the earliest indicator of thyroid underfunction.

• Free T4: The main circulating hormone; low levels confirm overt hypothyroidism.

• Free T3: The biologically active hormone; identifies why symptoms may persist even when T4 is borderline.

• TPOAb (thyroid peroxidase antibodies): An autoimmune marker for Hashimoto’s; predicts if borderline TSH will progress to full hypothyroidism.

• Total cholesterol & LDL: Elevated "bad" cholesterol is a classic metabolic consequence of low thyroid function.

Neck MRI Elfcare's full body MRI covers the neck soft tissues and can identify thyroid structural changes (enlargement, heterogeneous texture consistent with Hashimoto's, or nodules) that provide important context alongside blood results.

Why early detection matters

Hypothyroidism rarely happens overnight; your thyroid function often declines slowly, allowing your body to adapt to lower hormone levels. You might not realize how much your energy or focus has shifted until they are restored.

Early detection is vital because it catches subclinical hypothyroidism before symptoms like brain fog, persistent coldness, or fatigue become routine. During this silent phase, metabolic damage can already be occurring — cholesterol levels often rise, and the risk of cardiovascular strain increases.

For women, early awareness is particularly critical, as even subtle thyroid imbalances can significantly impact fertility and pregnancy outcomes. Identifying these shifts early empowers you to take proactive steps — through nutrition, monitoring, or medical consultation — rather than waiting for your body to reach a state of crisis.

In short: knowing your numbers early gives you the freedom to act before symptoms force you to.

How Elfcare can help

Elfcare's blood test includes TSH, Free T4, Free T3, and TPOAb — a complete thyroid profile that detects both hormonal underfunction and the autoimmune process most commonly driving it. This is one of the clearest examples of a blood test delivering direct, actionable clinical value: elevated TSH identifies the problem definitively, TPOAb identifies the cause, and the lipid profile reveals its downstream metabolic impact.

Our neck MRI adds structural context if thyroid enlargement or nodules are present.

If our blood tests identify thyroid dysfunction or related findings, we take care of further diagnostics or refer you to the appropriate specialist.