Hypothyroidism: The Symptoms of an Underactive Thyroid
When the thyroid works too little, everything slows — weight climbs, energy drops, you feel the cold. The symptoms arrive gradually, which is why it is so often caught late.
Hypothyroidism means the thyroid is making less hormone than the body needs. In plain terms the accelerator slows down, and almost everything shows it.
The commonest symptoms
- Weight gain with no change in diet
- Tiredness and sluggishness despite enough sleep
- Feeling the cold more than others
- Dry skin, hair thinning and falling
- Constipation
- Puffiness, particularly around the eyes
- A deeper, hoarser voice
- Poorer memory and concentration
- A persistently low mood
- Heavier or irregular periods
No single one of these means much on its own — they all have other causes. But three or four together, running for weeks, is worth a test.
Why it is more common in women
The usual cause is an autoimmune condition, where the body’s own defences affect the gland — and such conditions are seen more often in women. Some women also go through a temporary change after pregnancy.
Testing
TSH is checked first. When the thyroid is underactive, TSH comes back raised. Where needed, doctors add Free T4 and antibody tests.
Treatment
Usually a daily tablet that replaces the missing hormone. It is taken in the morning on an empty stomach with a gap before eating, because food reduces absorption. The dose is set from test results and adjusted over time.
Frequently asked questions
Is losing weight impossible with hypothyroidism?+
No. It feels harder while hormone levels are off; once treatment brings them into range, diet and activity work normally again.
Does it go away?+
Often it is a long-term condition managed with medication. Some temporary forms do resolve and treatment stops.
When should the tablet be taken?+
Generally in the morning on an empty stomach, with a gap before eating. Your doctor will confirm the routine.
Should I use more iodised salt?+
No. Ordinary use is enough; increasing iodine without advice does not help.