Underactive Thyroid: Symptoms, Tests, Treatment and Daily Support

Feeling tired all the time, cold when others are warm, gaining weight without a clear reason, or noticing dry skin and hair loss: these are common complaints, and many people blame stress or age. Sometimes the cause is an underactive thyroid, a very common and very treatable condition.

This guide explains what the thyroid does, what an underactive thyroid is, what the NHS says about symptoms, tests and treatment, and what daily habits can support you. It also looks at what Ayurveda and the old texts say about health, and where herbs and supplements can cause harm. It is education, not diagnosis.

What the thyroid does

The thyroid is a small butterfly-shaped gland at the front of your neck. It makes hormones that help control how your body uses energy. They affect your heartbeat, body temperature, digestion, weight, mood and more.

What an underactive thyroid is

The NHS describes an underactive thyroid, also called hypothyroidism, as a common condition in which the thyroid does not make enough hormones. It develops slowly, and it can be managed with treatment. Because the body slows down, many everyday functions slow down too.

Underactive Thyroid Symptoms

Symptoms can be mild and hard to notice, and they usually get worse over time. The NHS underactive thyroid page lists:

• extreme tiredness
• feeling cold more than usual
• weight gain
• constipation
• difficulty concentrating
• low mood or depression
• dry skin, dry hair or hair loss
• a hoarse voice
• irregular or heavy periods, if you have them

Many of these symptoms also have other causes. That is why a check is more reliable than guessing.

Underactive Thyroid Causes and Risk Factors

In the UK, the NHS says the main cause is Hashimoto’s disease, an autoimmune condition in which the immune system attacks the thyroid. Other causes include other thyroid conditions, surgery or radiotherapy on the neck, treatment for an overactive thyroid, and certain medicines. Iodine deficiency is a cause too, although the NHS says it is rare in the UK.

You are at higher risk if you:

• are a woman
• are aged about 30 to 50
• have a family history of thyroid or autoimmune conditions
• have had neck surgery, radiotherapy or treatment for an overactive thyroid

Anyone can develop it, so do not ignore symptoms because you do not fit this list.

Why tiredness needs a blood test

Tiredness is one of the most common symptoms in the world. It can come from poor sleep, stress, low iron, low vitamin D, depression, diabetes, thyroid problems and more. See our guides on why you may always feel tired and vitamin D in winter for other ideas.

The point is that you should not treat yourself with herbs or diets for months without finding the cause. A blood test is quick, and it can save you a lot of worry.

How an Underactive Thyroid Is Diagnosed (TSH Test)

The NHS says a doctor will ask about your symptoms, your family history of thyroid or autoimmune conditions, and any recent pregnancy, and may examine your neck. Blood tests measure thyroid-stimulating hormone (TSH) and thyroxine (T4). In some cases, you may be referred to a specialist.

Underactive Thyroid Treatment: Levothyroxine

The NHS says the usual treatment is levothyroxine tablets, which replace the missing hormone. They are typically taken for life. You will have regular blood tests to check the dose, because the wrong dose can cause side effects such as nausea, diarrhoea, headaches or sleep problems. Tell your doctor or pharmacist if you notice any.

• Take your tablet exactly as your doctor advises, usually at the same time each day.
• Ask your pharmacist whether to take it apart from certain foods, drinks or other medicines, as some can affect absorption.
• Do not stop or change the dose on your own.
• Keep up with your blood tests.

Untreated or poorly managed cases may raise the risk of heart problems and osteoporosis, says the NHS. Rarely, severe cases can lead to a life-threatening emergency called myxoedema coma, which is more common in older people. This is why treatment matters.

Daily habits that support you

Habits do not replace levothyroxine, but they help you feel better while treatment works:

• Keep a regular sleep schedule, and aim for 7 to 8 hours.
• Eat regular, balanced meals with plenty of vegetables, fruit, pulses and wholegrains.
• Add fibre and drink water, which helps with constipation.
• Walk or exercise gently most days, and build up slowly.
• Keep warm, and moisturise dry skin.
• Make time for rest and for people who support you.

Our guides to the Ayurvedic morning routine and natural daily energy without caffeine offer gentle ideas for energy.

Thyroid Diet: Food and Iodine, a Balanced View

Iodine helps the thyroid make hormones, but the NHS says deficiency is rare in the UK. In other parts of the world, iodised salt and diet matter more. It is not wise to take iodine or kelp supplements on your own, because too much iodine can also upset the thyroid. Ask your doctor first.

Some people ask about foods such as cabbage, cauliflower, broccoli and soy. In normal food amounts, these are healthy and do not need to be avoided by most people. If you have specific concerns, ask your doctor or a dietitian.

Movement, sleep and mood

Low mood and low energy are part of the condition for many people. Once treatment is stable, many feel better. In the meantime, gentle movement, daylight, and talking with a friend or counsellor can help. If you feel very low or hopeless, speak to your doctor. Our guide to why you may overthink may also be helpful.

What Ayurveda and the shastras say about health

Ayurveda does not describe the thyroid as modern medicine does, so we should not pretend that old texts diagnose it. But Ayurveda gives a beautiful, wide definition of a healthy person. The Sushruta Samhita says:

समदोषः समाग्निश्च समधातुमलक्रियः । प्रसन्नात्मेन्द्रियमनाः स्वस्थ इत्यभिधीयते ॥

samadoṣaḥ samāgniś ca samadhātu-malakriyaḥ | prasannātmendriya-manāḥ svastha ity abhidhīyate ||
Meaning: One whose bodily forces are in balance, whose digestion is balanced, whose tissues and waste functions are in order, and whose self, senses and mind are cheerful, is called healthy.

Sushruta Samhita, Sutrasthana 15.41

Notice that it includes the mind. Health is not only about lab numbers, but about energy, digestion, cheerfulness and balance. This is a lovely guide for daily living. It is not a way to diagnose or treat hypothyroidism, which needs a blood test and medicine. See our guide to Ayurveda and the Atharvaveda.

Herbs for Thyroid Problems: Take Care

Ashwagandha, guggul, kanchanar and other herbs are sometimes sold “for the thyroid”. Be careful:

• The NCCIH says there are few well-designed studies of Ayurvedic treatments, and some Ayurvedic products have been found to contain lead, mercury or arsenic.
• Some herbs and supplements can change thyroid hormone levels or affect how levothyroxine works.
• Never take them instead of prescribed medicine.
• Tell your doctor about everything you take, including our topic ashwagandha, before you start.

Pregnancy and thyroid

The NHS says that if you are pregnant or planning pregnancy, you should tell your doctor, because your dose may need to change. Thyroid hormones matter for a baby’s development, so regular checks are important. Never adjust the dose yourself.

When to see a doctor

See a doctor if you think you might have an underactive thyroid, as the NHS advises. Also see a doctor if you already take levothyroxine and your symptoms return, or you develop side effects. Get urgent help if someone with known thyroid disease becomes very drowsy, confused, very cold or unresponsive.

Common myths

• Myth: thyroid problems can be cured with diet alone. No diet replaces treatment.
• Myth: levothyroxine is addictive or harmful. It replaces a hormone your body needs, and it is safe when the dose is right.
• Myth: only overweight people have a slow thyroid. Many do not.
• Myth: a thyroid herb is better than a tablet. There is no proof of this.
• Myth: I can stop tablets when I feel well. You usually need them long term.

Living well with an underactive thyroid

Once your dose is right, many people feel much better, but the first months can be a time of adjustment. Be patient with yourself. Energy may return slowly, and you may need a few blood tests before your dose is settled.

• Keep a short diary of your symptoms, sleep and mood.
• Write down questions to ask at each check-up.
• Take your tablet at the same time each day, and set a reminder.
• Ask a family member to help you remember appointments.
• Do not compare yourself with others. Every body responds a little differently.

With care, most people with an underactive thyroid live full and active lives. It is a long-term condition, but not a limiting one.

Questions to ask at your thyroid check-up

A short list helps you get the most from your doctor’s time.

• What do my TSH and thyroxine results mean?
• Is my dose right, and when should I be tested again?
• Are my symptoms due to the thyroid, or could something else be involved?
• Should I take my tablet at a particular time or away from certain foods?
• Are any of my other medicines or supplements likely to interfere?
• Should any family members be checked?

Having clear answers helps you feel in control. If something is unclear, ask for it in writing.

Skin, hair and cold intolerance: practical help

Dry skin, hair thinning and feeling cold are common and can be upsetting. While treatment takes effect, some practical steps can help.

• Moisturise soon after washing, and use gentle, fragrance-free products.
• Wash hair with lukewarm water, and be gentle with brushing.
• Dress in layers, and keep your home comfortably warm.
• Eat enough protein, iron-rich foods and vitamin C, unless your doctor advises otherwise.
• Ask your doctor if hair loss continues after your thyroid levels are stable, as other causes may be involved.

These tips make daily life easier, but they do not replace correct treatment of the underlying condition.

Constipation and digestion

A slow thyroid can slow digestion, which causes constipation for many people. Tradition and modern advice agree on some simple steps:

• Eat more fibre from vegetables, fruit, pulses and wholegrains.
• Drink enough water through the day.
• Take a short walk after meals.
• Keep regular mealtimes and a regular toilet routine.
• Avoid harsh laxatives or herbal purgatives unless a doctor advises them.

If constipation is severe or sudden, or comes with pain, vomiting or blood, see a doctor promptly.

Mental wellbeing and an underactive thyroid

Low mood, poor concentration and anxiety can be part of thyroid problems, and living with a long-term condition can itself feel heavy. Talking to someone helps. You can speak to your doctor, a counsellor, or trusted friends and family.

Daily calm practices such as slow breathing, a short walk in daylight and a regular bedtime help many people. You can try our guides to alternate nostril breathing and yoga nidra as gentle supports. If your mood is very low, or you have thoughts of harming yourself, please reach out to a doctor or emergency services straight away.

Thyroid health and women’s life stages

The NHS notes that an underactive thyroid is more common in women, and it can affect periods, fertility and pregnancy. Heavy or irregular periods can be a sign. After pregnancy and around menopause, symptoms such as tiredness and low mood can overlap with thyroid problems, so it is worth asking about a check if you are unsure.

If you are trying to conceive, tell your doctor early. If you are already on levothyroxine and become pregnant, contact your doctor straight away, because the dose often needs changing. Do not wait for your next routine appointment.

Simple habits to start this week

If you have just been diagnosed or are waiting for results, here is a gentle plan for the next week. It does not replace medical care.

• Day 1: book your blood test or review appointment.
• Day 2: write down your symptoms and questions.
• Day 3: add a vegetable dish to your lunch and dinner.
• Day 4: take a 15-minute walk in daylight.
• Day 5: set a regular bedtime and a screen-free hour before it.
• Day 6: check any herbs or supplements you take, and list them for your doctor.
• Day 7: rest, and be kind to yourself.

Small steps taken calmly are more effective than a dramatic overhaul. If you want to read more on routines, try our guide to the Ayurvedic daily routine for immunity.

Putting tradition and science together

The best way to benefit from both Ayurveda and modern medicine is to give each its proper job. Use modern medicine to diagnose and treat the underactive thyroid. Use Ayurvedic ideas of regular routine, fresh food, early bedtime and calm to support your daily life.

Be wary of anyone who claims that a herb can “cure” an underactive thyroid, or tells you to stop tablets. Be equally open to the wisdom of a balanced, cheerful life that old texts describe. When the two are used together, with honesty and your doctor’s guidance, they can help you feel as well as possible.

Underactive Thyroid FAQs

What is an underactive thyroid?

It is when the thyroid gland does not make enough hormones, which slows many body functions.

What are the first signs of an underactive thyroid?

Tiredness, feeling cold, weight gain, constipation, low mood and dry skin are common. A blood test confirms it.

Can diet cure an underactive thyroid?

No. Healthy food supports wellbeing, but the NHS says treatment is usually levothyroxine.

Is it safe to take ashwagandha for thyroid problems?

Ask your doctor first. Herbs can affect thyroid levels and interact with medicine.

Can I lose weight with an underactive thyroid?

Yes, once treatment is stable and with healthy food and exercise. Ask your doctor for advice.

Further reading

• NHS: Underactive thyroid (hypothyroidism)
• NCCIH: Ayurvedic Medicine In Depth
• Our guide to why you may always feel tired

This article is for general education and cultural information, not medical advice. If symptoms persist or worry you, please speak with a qualified healthcare professional. Images on this page were created with AI.