Underactive thyroid (hypothyroidism)
Also called: underactive thyroid, low thyroid, hypothyroid, Hashimoto's disease, myxoedema
Hypothyroidism means the thyroid gland in your neck does not make enough thyroid hormone, so many body processes slow down. It often causes tiredness, feeling cold and weight gain. A simple blood test finds it, and a daily hormone tablet controls it well in most people.
General health information for Pakistan. It does not give doses or brand advice. If you are worried, or symptoms are severe, see a doctor. When to see a doctor
Overview
The thyroid is a small, butterfly-shaped gland at the front of the neck. It makes thyroid hormones, which set the speed of many body processes, such as how fast you use energy, how warm you feel and how your heart, gut and brain work. In hypothyroidism (underactive thyroid) the gland makes too little hormone, so these processes slow down.
It is a common condition. It is more common in women and becomes more likely as people get older. Symptoms usually come on slowly over months or years and can be mild, so many people do not know they have it. Worldwide, the most common cause is too little iodine in the diet. In countries with enough iodine, the most common cause is Hashimoto's disease, where the immune system (the body's defence system) attacks the thyroid by mistake. Some babies are born with an underactive thyroid (congenital hypothyroidism), which can harm growth and brain development if it is not treated early.
The good news is that hypothyroidism is easy to test for and treat. A daily tablet that replaces the missing hormone brings levels back to normal in most people. Treatment is usually lifelong, with regular blood tests to check the dose, and most people can live a normal life.
In Pakistan: what studies show
In Pakistan's 2018 national nutrition survey, 79.6% of households had properly iodised salt, but only 31.6% in the newly merged districts of Khyber Pakhtunkhwa. Newborn thyroid screening is patchy: in a national survey of doctors, only 41.3% were offering it.
- In the 2018 National Nutrition Survey, 79.6% of households in Pakistan had salt with enough iodine in it.[1] (national survey, data April 2018 - January 2019)
- The same 2018 survey found that only 31.6% of households in the newly merged districts of Khyber Pakhtunkhwa used iodised salt, the lowest of any area.[1] (national survey, data April 2018 - January 2019)
- In the 2018 national survey, the middle (median) urine iodine level in women of child-bearing age was 108.3 micrograms per litre, and the report says iodine deficiency was present in these women.[1] (national survey, data April 2018 - January 2019)
- In the same survey, the median urine iodine level in school-age children aged 6 to 12 was 122.9 micrograms per litre.[1] (national survey, data April 2018 - January 2019)
- A study of 500 pregnant women at antenatal clinics in six Pakistani cities found that 1.6% had newly found mild (subclinical) hypothyroidism in early pregnancy.[2] (cross-sectional, data January 2017 - January 2018)
- A newborn screening programme at Aga Khan University hospitals in Karachi found that about 1 in 1126 screened babies was born with an underactive thyroid (27 babies).[3] (cross-sectional, data January 2019 - December 2023 (methods section says to December 2022))
- The same Karachi programme screened 30,402 newborns over four years, reaching 96.2% of babies born in its hospitals.[3] (cross-sectional, data January 2019 - December 2023 (methods section says to December 2022))
- In a national online survey of 341 doctors, mostly child specialists, only 41.3% were offering newborn screening for congenital hypothyroidism in their practice.[4] (cross-sectional survey, data not stated)
What we do not know yet: No national or community-based study of hypothyroidism in Pakistani adults or women was found; the available numbers come from hospital and clinic studies. The 2018 survey report is itself unclear on whether average iodine intake is adequate or deficient, and newborn screening data come mainly from one private hospital network in Karachi.
Pakistan studies cited
- Ministry of National Health Services, Regulations and Coordination (Nutrition Wing), Government of Pakistan; UNICEF Pakistan; Aga Khan University National Nutrition Survey 2018: Key Findings Report. Government of Pakistan and UNICEF Pakistan 2018 (survey year; publication date not stated on the opened page). Open source
- Sohail R, Yasmin H, Tasneem N, et al. The Prevalence of Subclinical Hypothyroidism During Early Pregnancy in Pakistan: A Cross-Sectional Study. Cureus 2021;13(12):e20316. doi:10.7759/cureus.20316. Open source
- Majid H, Jafri L, Ahmed S, et al. Establishing a Newborn Screening Programme: A Success Story from a Low-Resource Setting. Journal of the College of Physicians and Surgeons Pakistan 2025;not stated. doi:10.29271/jcpsp.2025.03.387. Open source
- Khan SA, Aftab S, Khan YN, et al. A National Survey on Congenital Hypothyroidism Newborn Screening in Pakistan. Global Pediatric Health 2024;11. doi:10.1177/2333794X241293526. Open source
Symptoms
- Feeling very tired (fatigue) and weak
- Feeling cold more easily than other people
- Weight gain
- Constipation
- Dry skin, dry or thinning hair and brittle nails
- Low mood (depression), poor memory or trouble concentrating
- Muscle aches, cramps or joint pain
- Heavier or irregular periods
- A hoarse (rough) voice
- Later signs if untreated: a puffy face, hands and feet, slow speech, thinning eyebrows and a slow heartbeat
Causes and risk factors
Causes
- Too little iodine in the diet: the body needs iodine to make thyroid hormone, and this is the most common cause worldwide
- Hashimoto's disease: an autoimmune condition where the immune system damages the thyroid; the main cause in countries with enough iodine
- Thyroiditis (inflammation of the thyroid), for example after a viral infection or after having a baby (postpartum thyroiditis)
- Treatment of the thyroid: surgery to remove it, radioactive iodine, or radiotherapy to the neck or head
- Some medicines, such as lithium and amiodarone, and some cancer treatments
- Problems present from birth (congenital) or, less often, a problem with the pituitary gland in the brain, which controls the thyroid (central hypothyroidism)
What makes it more likely
- Being a woman
- Getting older (more common after the age of 50)
- A family history of thyroid disease
- Having another autoimmune condition, such as type 1 diabetes
- Past thyroid surgery, radioactive iodine treatment or radiotherapy to the neck
- Taking medicines that can affect the thyroid, such as lithium or amiodarone
- Recently having a baby
- Living in an area where the diet is low in iodine
Complications
When hypothyroidism is not treated, or the dose of treatment is wrong, it can raise cholesterol and increase the risk of heart disease and heart failure. Too much treatment over a long time can weaken the bones (osteoporosis) and strain the heart. In pregnancy, an untreated underactive thyroid raises the chance of miscarriage, pre-eclampsia (high blood pressure in pregnancy), early birth and problems for the baby. It can also make it harder to get pregnant. In babies and children, untreated hypothyroidism can slow growth and brain development. Very rarely, severe untreated hypothyroidism leads to myxoedema coma, a life-threatening emergency. It is more common in older people and can be set off by infection, cold, some medicines or missed doses.
When to see a doctor
- Emergency: a person with known or suspected hypothyroidism becomes very drowsy, confused or hard to wake, feels very cold, or breathes slowly. This may be myxoedema coma. Go to hospital straight away.
- Chest pain or a fast or pounding heartbeat after starting or changing thyroid treatment
- Shaking, sweating, feeling anxious or losing weight quickly while on treatment, which can mean the dose is too high
- You have an underactive thyroid and find out you are pregnant, or are planning a pregnancy: see your doctor early, as the dose often needs to change
- A baby or child who is not growing well, is slow to reach milestones (sitting, walking, talking) or seems unusually sleepy and constipated
- Symptoms that get worse, do not improve, or new symptoms appear while on treatment
Diagnosis
Hypothyroidism is found with a blood test. The main test is TSH (thyroid-stimulating hormone), a signal from the pituitary gland that rises when the thyroid is not working hard enough. If TSH is high, the laboratory also measures free T4 (the main thyroid hormone). A high TSH with a low free T4 means hypothyroidism. A high TSH with a normal free T4 is called subclinical (mild) hypothyroidism. The test is often repeated to confirm the result, and it is best not done during a sudden illness. A thyroid antibody test (TPO antibodies) may be done once to look for Hashimoto's disease. Tell your doctor if you take biotin supplements, as they can give false results. Your doctor may also check cholesterol, a blood count and other tests. In many countries, newborn babies have a heel-prick blood test so that congenital hypothyroidism is found and treated early.
Treatment
- Confirm the diagnosis with blood tests (TSH and free T4) before starting treatment.
- Take thyroid hormone replacement (levothyroxine) every day. Your doctor decides the dose; older people and people with heart disease usually start low and increase slowly.
- Have a TSH blood test every few months after starting or changing the dose until the level is stable, then about once a year. Symptoms can take weeks to months to improve.
- For mild (subclinical) hypothyroidism, your doctor decides whether to treat or just repeat the tests, based on how high TSH is, your age and your symptoms.
- Do not use T3 (liothyronine) alone or with levothyroxine, or animal (natural) thyroid extract, unless a specialist advises it; guidelines do not recommend them for routine use.
- If you become pregnant or plan a pregnancy, see your doctor early: the dose often needs to go up and blood tests are checked more often.
- Very severe hypothyroidism or myxoedema coma is treated in hospital, where thyroid hormone can be given by injection.
Medicines in Pakistan
Medicines a doctor may use, by group. Each link opens our page for that medicine, with every brand and its official DRAP price. Your doctor decides which medicine and dose are right for you.
| Group | Role | Medicines |
|---|---|---|
| Thyroid hormone replacement (T4) tablets | first choice for almost everyone with hypothyroidism; replaces the missing hormone and is usually taken for life, with the dose checked by blood tests | Levothyroxine sodium (17 brands) |
| Thyroid hormone replacement by injection | used in hospital for very severe hypothyroidism or myxoedema coma, when tablets are not suitable | Levothyroxine sodium (17 brands) |
Also used (not yet in our price list): Liothyronine (T3): not for routine use; only in special cases under a specialist
Self-care and prevention
Self-care
- Take your thyroid tablet at the same time every day, on an empty stomach with water only
- Keep calcium, iron, antacids and soy products a few hours apart from your thyroid tablet, as they can stop it being absorbed; ask your pharmacist about timing
- Avoid taking your thyroid tablet with coffee or grapefruit juice
- Try to stay on the same manufacturer's product; if it changes, ask for a TSH test a few weeks later
- Do not stop treatment on your own, even when you feel well
- Keep all your blood test appointments so the dose stays right
- Tell your doctor or pharmacist about every other medicine and supplement you take, including over-the-counter ones and biotin
- Do not take kelp, iodine or herbal 'thyroid support' supplements; they do not treat hypothyroidism and can delay proper care
Prevention
- Make sure your diet contains enough iodine, since iodine deficiency is the leading cause of hypothyroidism worldwide
- Avoid high-dose iodine or kelp supplements unless a doctor advises them, as too much iodine can also harm the thyroid
- Ask for newborn thyroid screening (heel-prick test) for your baby where it is available, so congenital hypothyroidism is treated early
- If you have type 1 diabetes or another autoimmune disease, ask your doctor whether you need thyroid tests
- If you already have hypothyroidism, taking treatment regularly and keeping blood tests helps prevent heart, bone and pregnancy problems
Common questions
Will I need thyroid tablets for the rest of my life?
Most people with hypothyroidism need treatment for life, because the thyroid does not usually recover. The tablet does not cure the condition, but it controls it completely in most people. Your doctor checks your blood regularly to keep the dose right.
Can I stop my thyroid tablets when I feel better?
No. You feel better because the tablet is replacing the missing hormone. If you stop, your hormone level will fall again and symptoms will come back. Missing an odd dose is not serious, but talk to your doctor if you often forget.
Can I get pregnant if I have an underactive thyroid?
Yes. Well-treated hypothyroidism does not usually stop a healthy pregnancy, and thyroid hormone tablets are considered safe in pregnancy. See your doctor before trying or as soon as you know you are pregnant, because the dose often needs to increase and blood tests are needed more often.
Are natural thyroid extract or herbal remedies better than tablets?
No. Thyroid guidelines do not recommend animal (natural) thyroid extract, because its strength varies and it is not the same as human hormone. Kelp, iodine and herbal supplements do not treat hypothyroidism and may delay the right treatment.
Do other medicines or foods affect my thyroid tablet?
Yes. Calcium, iron, some antacids and soy can reduce how much of the tablet your body absorbs, so they should be taken a few hours apart. Coffee and grapefruit juice can also interfere. Your pharmacist can help you plan the timing of your medicines.
Sources
- NICE. Thyroid disease: assessment and management (NICE guideline NG145) (2023).
- NICE. October 2025 exceptional surveillance of thyroid disease: assessment and management (NICE guideline NG145) (2025).
- American Thyroid Association. Hypothyroidism (patient education booklet) (2019).
- NHS. Underactive thyroid (hypothyroidism) (2025).
- MedlinePlus (US National Library of Medicine). Hypothyroidism: MedlinePlus Medical Encyclopedia (2024).
- StatPearls, NCBI Bookshelf. Hypothyroidism (Nursing) (2024).
- Journal of the Pakistan Medical Association. Is delayed diagnosis of hypothyroidism still a problem in Faisalabad, Pakistan (2008).
- Annals of King Edward Medical University. Delayed Diagnosis of Congenital hypothyroidism of Diverse Aetiology in Pakistan. An Experience from a Tertiary Care Hospital (2022).
Prepared from the sources listed below by the MedInfoBase team. Last reviewed 16 October 2026. This page is general health information, not medical advice. It gives no doses and does not replace a doctor: talk to your doctor or pharmacist before starting, stopping or changing any medicine. How we write and check our pages.
Related conditions
Overactive thyroid (hyperthyroidism)DepressionHeart failureHigh cholesterol (dyslipidaemia)