Underactive thyroid (hypothyroidism)

An underactive thyroid gland (hypothyroidism) means your thyroid gland doesn't produce enough thyroid hormone. The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). Both men and women can have an underactive thyroid, although it's more common in women than in men.

Symptoms of underactive thyroid 

The function of the thyroid gland is to produce hormones. These hormones help regulate the body's metabolism (the process that turns food into energy). 

Many symptoms of an underactive thyroid (hypothyroidism) are the same as those of other conditions. So an underactive thyroid can easily be confused for something else.

Symptoms usually develop slowly. You may not realise you have a medical problem for several years.

Common symptoms and signs include:

  • tiredness
  • being sensitive to cold
  • weight gain
  • constipation
  • depression
  • slow movements and thoughts
  • hoarseness or deepening of the voice
  • muscle aches and weakness
  • muscle cramps
  • ‘pins and needles’ sensation in the hands
  • dry and scaly skin
  • brittle hair and nails
  • reduced body and scalp hair (for example sparse eyebrows)
  • puffy face, hands and feet (myxoedema)
  • loss of libido (sex drive)
  • pain, numbness and a tingling sensation in the hand and fingers (carpal tunnel syndrome)
  • irregular periods or heavy periods

Elderly people with an underactive thyroid may develop memory problems and depression. Children may experience slower growth and development. Teenagers may start puberty earlier than normal.

If you have any of these symptoms, see your GP and ask to be tested for an underactive thyroid.

The thyroid gland 

The thyroid gland is a small butterfly-shaped gland in the neck. It is just in front of the windpipe (trachea).

One of its main functions is to produce hormones. These help to control the body's metabolism (the process that turns food into energy). These hormones are called triiodothyronine (T3) and thyroxine (T4).

Many of the body's functions slow down when the thyroid doesn't produce enough of these hormones.

When to see your GP 

Symptoms of an underactive thyroid (see above) are often similar to those of other conditions. The symptoms usually develop slowly, so you may not notice them for years.

You should see your GP and ask to be tested for an underactive thyroid if you have a combination of the following symptoms including:

  • tiredness
  • weight gain (unexplained)
  • depression 
  • being sensitive to the cold
  • dry skin and hair
  • muscle aches

The only accurate way of finding out whether you have a thyroid problem is to have a thyroid function test. This is when a sample of blood is tested to measure your hormone levels.

Treating an underactive thyroid 

An underactive thyroid can often be successfully treated by taking daily hormone tablets to replace the hormones your thyroid isn't making.

These hormone replacement tablets are called levothyroxine and  raise your thyroxine levels.

You'll usually need treatment for the rest of your life. However, with proper treatment, you should be able to lead a normal, healthy life.

If an underactive thyroid isn't treated, it can lead to complications, including:

  • heart disease
  • goitre (swelling of the thyroid gland that causes a lump to form in the throat)
  • pregnancy problems
  • a life-threatening condition called myxoedema coma (although this is very rare)

Who's affected

Both men and women can have an underactive thyroid, although it's more common in women. Children can also develop an underactive thyroid.

All babies born in Northern Ireland are screened for congenital hypothyroidism using a blood spot test when the baby is about five days old.

Causes of underactive thyroid 

There's no way of preventing an underactive thyroid. 

An underactive thyroid (hypothyroidism) is when your thyroid gland doesn't produce enough of the hormone thyroxine (also called T4).

Most cases of an underactive thyroid are caused by the immune system attacking the thyroid gland and damaging it.

Thyroid damage can also occur after thyroid or other neck surgery, or external radiotherapy for cancer treatment.

The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was reviewed August 2018

This page is due for review August 2021

Health conditions A to Z

Search by health condition or symptoms

Or find conditions beginning with …

Share this page

What do you want to do?
What is your question about?
Do you want a reply?
Your email address
To reply to you, we need your email address
Your feedback

We will not reply to your feedback.  Don't include any personal or financial information, for example National Insurance, credit card numbers, or phone numbers.

This feedback form is for issues with the nidirect website only.

You can use it to report a problem or suggest an improvement to a webpage.

If you have a question about a government service or policy, you should contact the relevant government organisation directly as we don’t have access to information about you held by government departments.

You must be aged 13 years or older - if you’re younger, ask someone with parental responsibility to send the feedback for you.

The nidirect privacy notice applies to any information you send on this feedback form.

Don't include any personal or financial information, for example National Insurance, credit card numbers, or phone numbers.

Plain text only, 750 characters maximum.
Plain text only, 750 characters maximum.

What to do next

Comments or queries about angling can be emailed to anglingcorrespondence@daera-ni.gov.uk 

What to do next

If you have a comment or query about benefits, you will need to contact the government department or agency which handles that benefit.  Contacts for common benefits are listed below.

Carer's Allowance

Call 0800 587 0912
Email 
dcs.incomingpostteamdhc2@nissa.gsi.gov.uk

Discretionary support / Short-term benefit advance

Call 0800 587 2750 
Email 
customerservice.unit@communities-ni.gov.uk

Disability Living Allowance

Call 0800 587 0912 
Email dcs.incomingpostteamdhc2@nissa.gsi.gov.uk

Employment and Support Allowance

Call 0800 587 1377

Jobseeker’s Allowance

Contact your local Jobs & Benefits office

Personal Independence Payment

Call 0800 587 0932

If your query is about another benefit, select ‘Other’ from the drop-down menu above.

What to do next

Comments or queries about the Blue Badge scheme can be emailed to bluebadges@infrastructure-ni.gov.uk or you can also call 0300 200 7818.

What to do next

For queries or advice about careers, contact the Careers Service.

What to do next

For queries or advice about Child Maintenance, contact the Child Maintenance Service.

What to do next

For queries or advice about claiming compensation due to a road problem, contact DFI Roads claim unit.

What to do next

For queries or advice about criminal record checks, email ani@accessni.gov.uk

What to do next

Application and payment queries can be emailed to ema_ni@slc.co.uk

What to do next

For queries or advice about employment rights, contact the Labour Relations Agency.

What to do next

For queries or advice about birth, death, marriage and civil partnership certificates and research, contact the General Register Office Northern Ireland (GRONI) by email gro_nisra@finance-ni.gov.uk

What to do next

For queries about:

If your query is about another topic, select ‘Other’ from the drop-down menu above.

What to do next

For queries or advice about passports, contact HM Passport Office.

What to do next

For queries or advice about Penalty Charge Notices (PCNs), including parking tickets and bus lane PCNs, email dcu@infrastructure-ni.gov.uk

What to do next

For queries or advice about pensions, contact the Northern Ireland Pension Centre.

What to do next

If you wish to report a problem with a road or street you can do so online in this section.

If you wish to check on a problem or fault you have already reported, contact DfI Roads.

What to do next

For queries or advice about historical, social or cultural records relating to Northern Ireland, use the Public Record Office of Northern Ireland (PRONI) enquiry service.

What to do next

For queries or advice about rates, email LPSCustomerTeam@lpsni.gov.uk

What to do next

For queries or advice about  60+ and Senior Citizen SmartPasses (which can be used to get concessionary travel on public transport), contact Smartpass - Translink.