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Hypothyroidism is an underactive thyroid, which does not make enough thyroid hormone. Your endocrinologist will interpret your thyroid-stimulating hormone (TSH) and free T4 blood tests together to make a diagnosis. When thyroid hormone replacement is needed, the usual treatment is a daily levothyroxine tablet. We re-check your level around six to eight weeks after you start and adjust the dose if needed. Endocare treats hypothyroidism in the UAE at our clinic in Dubai Healthcare City.
- A raised TSH with a low free T4 points to overt hypothyroidism, while a raised TSH with a normal free T4 points to subclinical hypothyroidism.
- A 2025 study at Dubai Health primary care centres found hypothyroidism in 2.1% of adults referred for a thyroid function test, most of them women.
- The UK National Institute for Health and Care Excellence (NICE) advises considering levothyroxine when TSH is 10 mIU/litre or higher on two tests three months apart.
- Calcium and iron supplements can reduce how much levothyroxine is absorbed, so the prescribing information advises keeping them at least four hours apart.
- Where symptoms continue after TSH is back in the reference range, your endocrinologist will look for other causes before considering a change of dose.
- NICE does not recommend routinely offering liothyronine (T3), and recommends against natural thyroid extract, because there is not enough evidence of benefit over levothyroxine.
01 Introduction
An underactive thyroid produces too little of the hormone that helps regulate the body’s metabolic rate. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) reports that nearly 5 out of 100 Americans aged 12 and older have hypothyroidism. NIDDK also notes that most cases are mild or have few obvious symptoms. Hypothyroidism is one of the thyroid conditions our endocrinologists treat at our Dubai clinic.
02 What hypothyroidism is
The pituitary gland controls the thyroid by releasing thyroid-stimulating hormone (TSH). When the thyroid cannot produce enough hormone, the pituitary releases more TSH. TSH therefore rises while the thyroid hormone level falls. A raised TSH is often the first sign of an underactive thyroid, sometimes before free T4 has fallen below the reference range.
03 The symptoms of an underactive thyroid
NIDDK lists the symptoms of hypothyroidism as follows.
- Fatigue
- Weight gain
- Trouble tolerating cold
- Joint and muscle pain
- Dry skin, or dry and thinning hair
- Heavy or irregular menstrual periods, and fertility problems
- A slowed heart rate
- Depression
Feeling well does not rule the condition out, because many cases are mild. Each of these symptoms is also common in people with a normal thyroid, so your endocrinologist will confirm the diagnosis with blood tests.
04 What causes an underactive thyroid
NIDDK lists the causes of hypothyroidism as including the following.
- Hashimoto’s disease, an autoimmune condition and the most common cause
- Thyroiditis, meaning inflammation of the thyroid gland
- Congenital hypothyroidism, present from birth
- Surgical removal of the thyroid
- Radiation treatment to the neck
- Certain medicines
- Less often, an iodine imbalance or a disorder of the pituitary gland or hypothalamus
Your endocrinologist will diagnose Hashimoto’s thyroiditis with a thyroid antibody test alongside thyroid function tests. Where the thyroid has been removed, hormone replacement is part of care after thyroid surgery.
05 Who should be tested for an underactive thyroid
We recommend a thyroid function test if you have symptoms from the list above. Testing is also reasonable in several situations where symptoms may be absent or easily attributed to something else.
- A family history of thyroid disease
- Another autoimmune condition
- Previous thyroid surgery, or radiation treatment to the neck
- Pregnancy, or planning a pregnancy
- Having been pregnant in the past six months
- Age over 60
- A raised cholesterol result with no other explanation
NIDDK notes that women are much more likely than men to develop hypothyroidism. In the UAE, you can see an endocrinologist directly, with no GP referral needed, for concerns related to hormones, weight, metabolism or blood sugar. If you plan to use health insurance, we recommend checking your policy before you book, because some insurers require a referral or pre-approval.
06 How hypothyroidism is diagnosed
What your TSH and free T4 results mean together
Your endocrinologist will read TSH alongside free T4, because the two results together identify which form of the condition you have and what happens next.
| Result pattern | What it indicates | What your endocrinologist will do |
|---|---|---|
| Raised TSH with a low free T4 | Overt hypothyroidism | Start levothyroxine and re-check your level around six to eight weeks later |
| Raised TSH with a normal free T4 | Subclinical hypothyroidism | Repeat the test after three months before deciding whether to treat |
| Normal TSH with a normal free T4 | Normal thyroid function | Look elsewhere for the cause of your symptoms |
| Low or normal TSH with a low free T4 | An uncommon pattern that can point to the pituitary gland | Investigate further before starting treatment |
The definitions in this table follow NIDDK and the UK National Institute for Health and Care Excellence (NICE). Laboratories publish their own reference ranges, and the range used in pregnancy differs from the range used outside it. Your endocrinologist will read your result against your own laboratory’s range.
Subclinical hypothyroidism, and when it is treated
Subclinical hypothyroidism means a raised TSH with a free T4 still inside the reference range. For adults whose TSH is 10 mIU/litre or higher on two separate occasions three months apart, the NICE thyroid disease guideline recommends considering levothyroxine. For adults under 65 with symptoms of hypothyroidism, whose TSH is above the reference range but below 10 mIU/litre on two occasions three months apart, NICE recommends considering a six-month trial of levothyroxine. A single raised TSH result can be temporary, which is why your endocrinologist will repeat the test.
Thyroid antibodies, and what a positive result tells you
NIDDK states that thyroid peroxidase antibodies are present in most people with Hashimoto’s disease. A positive antibody result can identify the cause of an underactive thyroid. Your endocrinologist will base the treatment decision on your TSH and free T4.
07 How an underactive thyroid is treated
How levothyroxine is taken
Levothyroxine is a thyroid hormone medication identical to the hormone a healthy thyroid makes. NIDDK states that your doctor may recommend taking it in the morning before eating. The US prescribing information for Euthyrox, one brand of levothyroxine, advises taking it on an empty stomach, half an hour to one hour before breakfast. We recommend agreeing the timing that suits your routine with your endocrinologist.
How your dose is found
Your endocrinologist will set your starting dose based on factors such as your age, your weight, your heart health and how long your thyroid has been underactive. NIDDK advises a blood test around six to eight weeks after you begin treatment, and another after each dose change. NICE advises aiming to keep TSH within the reference range.
Reaching that target can take more than one adjustment. NICE notes that TSH can take up to six months to return to the reference range in patients who had a very high level before treatment started.
Supplements, medications and foods that can affect treatment
Some supplements, medications and foods can reduce how much levothyroxine your body absorbs. The prescribing information advises taking levothyroxine at least four hours apart from calcium carbonate and iron supplements. We recommend telling your endocrinologist about every supplement and medication you take, because your endocrinologist sets your dose against your current routine.
- Calcium and iron supplements
- Antacids and some indigestion medicines
- Foods with large amounts of iodine, such as kelp, dulse and other seaweed
- Iodine supplements, and some cough medicines that contain iodine
NIDDK states that eating foods with large amounts of iodine may cause hypothyroidism or make it worse. It also states that iodine supplements can have the same effect. We recommend avoiding iodine supplements unless your endocrinologist has advised one.
08 How often your thyroid is re-tested
Regular blood tests help your endocrinologist confirm that your dose is still right for you. NICE advises waiting at least six weeks after the most recent thyroid function test before repeating it when symptoms change. Once you are taking levothyroxine, NICE suggests considering TSH tests every three months until two similar results within the reference range, taken three months apart, show that the level is stable. After that, NICE suggests a yearly test.
09 When symptoms persist and the blood test is normal
Some patients continue to feel unwell after their TSH has returned to the reference range. Your endocrinologist will first repeat the result, because a single reading can be misleading. Your endocrinologist will also review when you take your tablet and anything you take alongside it, because absorption can be affected. Your endocrinologist will also consider other conditions with similar symptoms, including anaemia, low vitamin D, sleep disorders and depression.
NICE advises against levothyroxine doses that suppress TSH, even when symptoms persist. NIDDK states that taking too much thyroid hormone medication can cause serious problems, such as an irregular heart rhythm called atrial fibrillation, or osteoporosis.
10 Is liothyronine (T3) or natural desiccated thyroid an option?
NICE recommends not routinely offering liothyronine for primary hypothyroidism, either alone or in combination with levothyroxine, because there is not enough evidence that it offers benefits over levothyroxine alone. NICE also recommends not offering natural thyroid extract, for the same reason. Where you have tried one of these, we recommend telling your endocrinologist, because it changes how your results are interpreted.
11 Hypothyroidism in pregnancy and when you are planning one
NIDDK states that many women taking thyroid hormone medication need a higher dose during pregnancy. The reference range used to read TSH also changes in pregnancy. NIDDK also states that, left untreated, hypothyroidism during pregnancy can affect both mother and baby. We recommend telling your endocrinologist as soon as you are pregnant or planning a pregnancy, because your dose and your testing interval may change.
12 What happens if an underactive thyroid is left untreated
NIDDK states that hypothyroidism can contribute to high cholesterol. Rarely, severe untreated hypothyroidism may lead to myxoedema coma, which NIDDK describes as an extreme form of hypothyroidism in which the body’s functions slow to a life-threatening point. In its common autoimmune form, the condition can progress over time, so a level that is only mildly abnormal today may fall further.
13 Hypothyroidism in the UAE
A Dubai primary care study published in BMC Public Health in 2025 reviewed 77,758 adults who attended Dubai Health primary healthcare centres for a thyroid function test between 2018 and 2020. The authors found hypothyroidism in 2.1% of them. Women made up 81.5% of those patients. The highest rate, 2.52%, was in the 35 to 44 age group. The authors note that the study included only patients referred for a thyroid test, which limits how far the figure applies to the wider population.
The Iodine Global Network classifies iodine intake in the UAE as adequate, based on a national survey of school-age children in 2008 to 2009. Iodine deficiency is therefore unlikely to be a common cause of an underactive thyroid here.
Ramadan raises a practical question each year. Meal times change during the fast, which affects when levothyroxine can be taken on an empty stomach. We recommend agreeing the timing of your dose with your endocrinologist before Ramadan begins.
14 Hypothyroidism and body weight
An underactive thyroid can slow the rate at which the body uses energy and can lead to some weight gain. The British Thyroid Foundation states that most of the extra weight gained with hypothyroidism is salt and water. The Dubai study found obesity in 47.0% of the patients with hypothyroidism and in 39.8% of those without it. This is an association, and it does not show that the thyroid caused the weight gain. Where weight remains a concern once your thyroid levels are stable, our endocrinologists can advise on losing weight with an underactive thyroid. They can also explain how thyroid disorders affect body weight in your own case.
15 What your care at Endocare involves
Your first appointment is a full medical assessment. Your endocrinologist will review your symptoms, your medical history and your thyroid blood tests, examine your neck, and explain what your results mean. Where possible, your first appointment takes place in person at Endocare’s Dubai clinic, as the physical examination and body composition analysis cannot be completed remotely.
Because thyroid hormone affects how the body uses energy, an underactive thyroid can change body composition as well as weight. At Endocare, body composition analysis is included free of charge at every consultation. Body composition analysis estimates body fat, muscle mass and body water. Repeated measurements help your endocrinologist understand how your body is changing beyond the number on the scale.
Follow-up appointments can be held in person at the clinic or online. Your endocrinologist will arrange the blood tests your treatment calls for.
16 FAQ
What is the most effective treatment for hypothyroidism?
NIDDK describes levothyroxine, which is identical to the natural thyroid hormone thyroxine (T4), as the recommended way to treat hypothyroidism. Your endocrinologist will adjust the dose until your TSH is within the reference range.
What is a normal TSH level?
There is no single figure that applies everywhere, because each laboratory publishes its own reference range and the range in pregnancy differs from the range outside it. Your endocrinologist reads your TSH against your own laboratory’s range and alongside your free T4.
How long does levothyroxine take to work?
NIDDK advises a blood test around six to eight weeks after starting treatment. Symptoms can improve gradually over the first weeks of treatment. In people who had a very high TSH before treatment, NICE notes that it can take up to six months to return to the reference range.
Do I have to take levothyroxine for life?
Often, yes, because the most common causes do not reverse. Hypothyroidism caused by a temporary thyroiditis can recover. Your endocrinologist can check for this with blood tests. NIDDK advises never stopping your thyroid medication without talking with your doctor first.
Does an underactive thyroid affect fertility or pregnancy?
It can. NIDDK lists heavy or irregular periods and fertility problems among the symptoms of hypothyroidism. We recommend speaking to your endocrinologist if you are planning a pregnancy, so that they can check your thyroid levels before you conceive.
Our Dubai clinic is located in Building 27, Block B, Unit 504 B, Dubai Healthcare City. Opening hours are Sunday 10:00-20:00, Monday 08:30-18:30, and Tuesday to Thursday 10:00-20:00. The clinic is closed on Fridays. Free parking is available in the building and on the surrounding streets. For patients using public transport, Dubai Healthcare City Metro Station on the Green Line is the nearest stop.
Bring your most recent thyroid blood tests to your appointment, and a list of every medication and supplement you take, because both can affect the dose your endocrinologist sets.
To book a consultation, call our Dubai clinic on +971 4 285 3885.
Book Your Consultation
- Specialist consultation
- Personalized Coaching
- Body Composition Analysis