Hypothyroidism symptoms: How to spot an underactive thyroid fast

Feeling tired for no reason, gaining weight, and getting cold easily can all point to an underactive thyroid. Hypothyroidism happens when your thyroid gland does not make enough thyroid hormone. That hormone controls metabolism, energy, body temperature, digestion, and even mood. Knowing common symptoms helps you get tests and treatment sooner.

Common signs to watch

The most common symptom is persistent fatigue that does not clear with sleep. You may also notice unexplained weight gain despite no change in diet or exercise. Cold intolerance — feeling colder than others in the same room — is a frequent clue. Skin changes like dry, rough skin and thinning hair or hair loss show up for many people. Slower thinking, memory lapses, and low mood or mild depression are part of the picture. Women might see heavier or irregular periods and trouble conceiving. Constipation, muscle aches, slow heart rate, and higher cholesterol are other possible signs.

What to do next

Track what you feel for a couple of weeks. Note when symptoms started, how severe they are, and any medication or health changes. Take that list to your primary care doctor and ask for a thyroid blood test. The key labs are TSH and free T4. If those are off, your doctor may add antibodies to check for autoimmune thyroiditis (Hashimoto’s). Treatment usually means a daily pill called levothyroxine to replace missing hormone. Dosing is individualized and often adjusted after repeat blood tests in six to eight weeks.

Practical tips while you wait: Don’t stop any current medications without talking to your doctor. Keep a simple symptom diary — it helps your clinician see patterns. Small diet changes won’t fix hypothyroidism but can help symptoms: eat balanced meals, stay active with gentle exercise, and aim for steady sleep. If you have high cholesterol or persistent depression, mention those issues since they can improve after thyroid treatment.

Certain groups are more likely to develop hypothyroidism. Women over 50, people with a family history of thyroid disease, and anyone with autoimmune conditions like diabetes or celiac disease should be cautious. Some medicines — lithium, amiodarone and cancer drugs — can affect thyroid function. Pregnancy raises the need for monitoring because thyroid levels change and untreated hypothyroidism can harm the baby. If you fall into any of these groups, mention it when tested often.

When to seek urgent care: Severe symptoms like extreme drowsiness, very low body temperature, breathing problems, or fainting are rare but serious. Call emergency services if someone becomes confused, very weak, or difficult to wake.

Following up: Once treatment starts, expect blood tests every six to twelve weeks until levels are stable, then less often. Many people feel significant improvement in energy and mood within a few weeks after correct dosing. Keep communication open with your clinician, and bring up any new symptoms or side effects.

If you think your thyroid is acting up, a simple blood test is the first smart move. It’s straightforward, common, and treatable.