What are the early warning signs of thyroid problems?

How does your body feel when you have thyroid problems? From lack of energy to mood changes, we explore the early signs of thyroid conditions.

One in 20 people in the UK have a thyroid condition, with women six times more likely to be affected than men [1]. Unfortunately, many cases go undiagnosed — sometimes because symptoms are missed or confused with other conditions.

There are 19 common signs linked to an overactive or underactive thyroid. Early symptoms including tiredness and feeling low are often put down to a recent illness or a busy lifestyle. Thyroid problems are also often mistaken for menopause as they share several symptoms.

In this article, we explore the early warning signs of thyroid conditions and offer advice on investigating your symptoms.

We cover:

What does the thyroid do?

The thyroid is a small, butterfly-shaped gland in your neck, which produces the thyroid hormones, T3 and T4. Thyroid hormones play an important role in metabolism and affect everything from your heartbeat to your energy levels, and even how you think and feel.

What can go wrong with the thyroid?

Sometimes the thyroid can be underactive, causing thyroid hormone levels to become too low. An underactive thyroid (known as hypothyroidism) makes your body systems slow down.

Conversely, your thyroid can be overactive, leading to higher-than-normal thyroid hormone levels. This is known as hyperthyroidism, and it makes your body’s cells work too quickly. These are the two main types of thyroid disorders.

Thyroid conditions have many causes, but the most common is autoimmune thyroid disease, where the immune system mistakenly attacks the thyroid.

What are the early warning signs of thyroid problems?

As thyroid hormones have far-reaching effects on the body, thyroid dysfunction can impact everything from digestion to your body temperature.

19 signs of thyroid problems:

1. Feeling tired all the time – fatigue has many causes, but it’s a very common symptom of hypothyroidism. So, if you’re feeling weary in the morning despite a good night’s sleep, it could be a sign of an underactive thyroid. An overactive thyroid can also leave you feeling exhausted and play havoc with your sleep pattern.

2. Mood changes — feeling unusually low and don’t know why? Depression is a symptom of hypothyroidism, thought to be linked to the effect of low thyroid hormone levels on serotonin — a chemical in your body that’s thought to be a natural mood stabiliser. Hyperthyroidism can also affect your mood and is associated with mood swings, irritability, and anxiety.

3. Weight changes – many people with hypothyroidism gain weight despite maintaining the same diet and exercise habits. This condition can also make it difficult to lose weight despite cutting the calories. Conversely, weight loss without any obvious explanation could signal an overactive thyroid.

4. A swelling in your neck – a swollen thyroid gland (known as a goitre) can be a sign of a thyroid problem. Check for any lumps or swelling around your thyroid gland using our thyroid check video. If you notice anything that looks unusual, check in with your doctor.




5. Your internal thermostat is on the blink – if you’ve constantly got the chills, an underactive thyroid could be to blame. When your system is on a slow-down, less energy is burnt by your cells, creating less heat. An overactive thyroid, on the other hand, puts your energy-producing cells into overdrive, so you might sometimes feel too warm or sweat profusely.

6. Dry skin – hypothyroidism can cause dry, itchy, flaky skin. This dryness is often due to reduced sweating, which robs the skin of natural moisture. Skin issues such as an itchy rash, hives, or changes to skin pigmentation can be a sign of an overactive thyroid.

7. Hair loss or thinning – dry, brittle, or thinning hair and diffuse hair loss are common signs of an underactive thyroid. Low thyroid hormone levels disrupt hair growth, putting follicles into resting mode. This can affect hair on the head and body, including hair loss from the outer third of the eyebrows (eyebrow hypotrichosis) — a classic sign of hypothyroidism. Hyperthyroidism can also affect your hair and is associated with patchy hair loss or thinning. Nails can also become dry and brittle and develop ridges.

8. Heartbeat changes – when your system speeds up, your heartbeat does too. Hyperthyroidism is linked to heart palpitations, so you may have an irregular and/or unusually fast heartbeat. In contrast, you might notice your heart rate has slowed down if your thyroid is underactive.

9. Loss of interest in sex – your sexual desire can take a hit when you have a thyroid problem. One aspect of this could be the effect of thyroid hormone levels on testosterone — a hormone that’s linked to libido in men and women. Other thyroid-related symptoms such as fatigue and low mood can also play a part.

10. High blood pressure – thyroid hormones are involved in regulating your heart rate and maintaining blood vessel health. Unusually high and low thyroid hormone levels are linked to an increased risk of hypertension. If left untreated, this can increase your risk of cardiovascular disease, such as heart attacks and strokes.

11. Unpredictable bowels – constipation is a common symptom of an underactive thyroid, while hyperthyroidism can cause loose bowel movements or diarrhoea. If your thyroid is overactive, you might also feel the urge to urinate more frequently.

12. Your brain feels fuzzy – your cognitive function can be affected when your thyroid isn’t working properly. Brain fog, including forgetfulness and slow thoughts, is linked to hypothyroidism, while hyperthyroidism can leave you feeling unfocused and finding it difficult to concentrate.

13. Sleep struggles – an overactive thyroid can make you feel constantly wired, impacting your chances of a good night’s rest — some people with hyperthyroidism have insomnia. On the other hand, you may constantly crave a daytime nap if your thyroid is underactive. This condition is also linked to sleep apnoea, where your breathing stops and starts while you sleep.




14. Changes to your periods – if your thyroid is underactive, your periods may be longer, heavier, and closer together (you may also get more cramps), whereas high levels of thyroid hormone are linked to shorter, lighter, less frequent periods.

15. Difficulty getting pregnant – as thyroid conditions can lead to menstrual irregularities and interfere with ovulation, they can impact women’s fertility.

16. Appetite changes – feeling hungry all the time is a clue that your body’s digestive system may be working overtime due to hyperthyroidism. You may also experience persistent thirst. Hypothyroidism can affect your sense of taste and smell, impacting your enjoyment of food.

17. You find it hard to relax – hyperactivity is a common sign of an overactive thyroid. So, if you have lots of nervous energy, and feel jittery, twitchy, or trembly, this could be the cause. Are your movements slower than usual? An underactive thyroid could be the culprit.

18. Painful extremities and muscles – tingling, numbness, or pain in your arms, legs, feet, and hands can signal an underactive thyroid. Over time, low thyroid hormone levels can cause nerve damage, resulting in these tingles and twinges. Muscle aches and weakness are also features of thyroid conditions.

19. High cholesterol – your body needs thyroid hormones to make cholesterol and get rid of cholesterol it doesn’t need. So, if your thyroid hormone levels are low, your level of bad cholesterol (known as low-density lipoprotein or LDL) can increase. If left untreated, this could put you at higher risk of heart problems.

The following table highlights some of the contrasting signs and symptoms of hypo- and hyperthyroidism.


Underactive thyroid (hypothyroidism)

Overactive thyroid (hyperthyroidism)



Weight gain

Weight loss

Slow movements


Slow heartbeat

Fast heartbeat

Raised cholesterol levels

Reduced cholesterol levels


All these signs and symptoms can have several causes. If you’re experiencing any of them, we recommend you speak to your doctor.

For some people, symptoms of a thyroid problem can be mild, while for others, they may be severe, impacting their quality of life. Depending on the cause, they may develop suddenly over days or gradually over many months or years. It’s also rare to experience all the symptoms of hyperthyroidism or hypothyroidism.

How can I check myself for thyroid conditions?

If you’re experiencing any thyroid-related symptoms, a blood test is usually the first step. A blood test can check whether your thyroid hormone levels are within the normal range.

A comprehensive thyroid check like our Advanced Thyroid Function Blood Test can also help rule out other issues that may be causing your symptoms, such as a vitamin deficiency. Check out our Thyroid Blood Test Buying Guide to help find the right test for you.


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How will I know if I have thyroid problems?

A diagnosis is based on your symptoms and blood test results. Your doctor may also request further blood tests and investigations such as a thyroid scan.

If you’re diagnosed with a thyroid condition, the good news is that many symptoms can be well-managed with treatment.

Learn more in our Thyroid Hub. Thyroid UK and the British Thyroid Foundation also have valuable resources and offer advice and support.



1. University of Aberdeen (2023) The majority of thyroid patients still suffering years on from diagnosis. Available at: https://www.abdn.ac.uk/news/17040/#:~:text=One%20in%2020%20people%20in,from%20the%20condition%20than%20men. (Accessed: 04 March 2024).

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