Hypothyroidism Symptoms: The Signs That Should Make You Check
By the Mush n Go editorial team - 14 November 2026
By the Mush n Go editorial teamPublished 14 November 202611 min read
Thyroid
Hypothyroidism symptoms are those of a body running in slow motion: tiredness from the moment you wake, feeling the cold, moderate weight gain, dry skin, constipation, low mood, a duller memory, changes to your periods. No single sign is enough on its own: it is the combination, and above all a blood test measuring TSH, that makes the diagnosis.
The symptoms
Hypothyroidism symptoms, system by system.
The thyroid, a small gland at the base of the neck, makes the hormones T4 and T3, which set the speed at which every cell uses its energy. When it produces too little, everything slows down at once: body heat, heart, digestion, skin, mind. Tiredness almost always comes first. For the full approach, see our guide thyroid and fatigue: why you stay exhausted, even on treatment.
The signs of hypothyroidism creep in slowly, over months, sometimes years. They are easily put down to age, work or winter. The table below sorts them by system: the more rows you tick, the more justified a TSH test becomes.
| System | What you notice | What is going on |
|---|---|---|
| Energy | Tiredness from the moment you wake, needing more sleep, drowsiness | Cells produce less energy |
| Temperature | Feeling the cold, cold hands and feet | The body makes less heat |
| Weight | Moderate weight gain, puffy face and eyelids | Slower metabolism and water retention |
| Skin, hair, nails | Dry, pale skin, dry hair that falls out, brittle nails, thinning eyebrows | Tissue renewal slows down |
| Digestion | Constipation, bloating | The gut contracts less |
| Heart and muscles | Slow pulse, breathlessness on exertion, cramps, stiffness | The heart and muscles work in slow motion |
| Mood | Low mood, loss of drive, irritability | The nervous system is less stimulated |
| Memory | Forgetfulness, slowness, difficulty concentrating | The brain slows down too |
| Cycle | Heavier or irregular periods, lower libido | Thyroid hormones interact with sex hormones |
| Voice and neck | Lower or hoarse voice, sometimes a swollen neck (goitre) | Tissues become infiltrated and the gland may enlarge |
The blood test sometimes reveals other clues: cholesterol that rises for no reason, mild anaemia.
Hypothyroidism fatigue has a signature: it is there from the morning and barely eases with rest. Tiredness that comes and goes from day to day points more towards other causes, reviewed in our guide to persistent fatigue. As for slowness of thought, it has its own file: brain fog.
In women
Hypothyroidism symptoms in women: three key stages.
Hypothyroidism affects women far more often than men. In the large British Whickham survey, followed for twenty years, it appeared each year in 3.5 women per 1,000, against 0.6 men per 1,000. The most common cause is Hashimoto's thyroiditis, an autoimmune disease in which the immune system gradually attacks the gland.
In women, the general signs come with some of their own: heavier, longer or irregular periods, a lower libido, sometimes difficulty conceiving. Three stages of life deserve particular attention.
Planning a pregnancy and pregnancy
The need for thyroid hormones increases from the first trimester. Unusual tiredness, feeling the cold, irregular cycles before conception: talk to your doctor, who will measure your TSH.
After childbirth
Postpartum thyroiditis can occur in the year after birth. Tiredness, low mood, hair loss: it is easily mistaken for the exhaustion of the first months.
Perimenopause and beyond
Tiredness, weight gain, sleep and mood also change at this stage. The two pictures overlap, and hypothyroidism becomes more common with age.
At all three times, tiredness is quickly blamed on circumstances. A simple test sorts things out, especially if thyroid disease runs in the family. For your forties and beyond, our article on tiredness during the menopause continues this chapter.
The discreet form
Subclinical hypothyroidism: mild signs, a rising TSH.
Subclinical hypothyroidism, also called mild or early hypothyroidism, is the most common form. TSH is slightly high, but free T4 stays within the normal range: the thyroid is still doing its job, at the cost of greater effort. In the American NHANES III survey, 4.3% of the people examined were in this situation, against 0.3% for overt hypothyroidism.
The symptoms of subclinical hypothyroidism are mild or absent: a little tiredness, a new sensitivity to cold, drier skin. It is often discovered by chance, on a blood test ordered for another reason.
- First, confirm: a slightly high TSH is rechecked after a few weeks, because it varies from one sample to the next and sometimes returns to normal by itself.
- Look for the cause: the presence of anti-TPO antibodies points to autoimmune thyroiditis, with a greater likelihood of progressing to overt hypothyroidism.
- Decide case by case: European guidelines generally suggest treatment when TSH exceeds 10 mIU/L; below that, age, symptoms, antibodies and a plan to become pregnant guide the decision.
- Monitor: without treatment, TSH is rechecked at regular intervals, at the pace set by your doctor.
The TSH reference range also has to be read with age: it rises naturally over the decades, which your doctor takes into account after 65.
The comparison
Hypothyroidism or hyperthyroidism: two opposite pictures.
Both conditions cause tiredness, which feeds the confusion. But one puts the brakes on while the other speeds things up. In hypothyroidism, the gland produces too few hormones and TSH rises to stimulate it. In hyperthyroidism, it produces too many and TSH collapses.
| Sign | Hypothyroidism: everything slows down | Hyperthyroidism: everything speeds up |
|---|---|---|
| Tiredness | Heavy, from the moment you wake, with drowsiness | Jittery, with muscle weakness |
| Temperature | Feeling the cold | Heat poorly tolerated, sweating |
| Weight | Moderate weight gain | Weight loss despite a good appetite |
| Heart | Slow pulse | Palpitations, fast pulse |
| Digestion | Constipation | More frequent stools |
| Skin and hair | Dry skin, brittle hair | Warm, moist skin, fine hair |
| Mood | Low mood, slowness | Nervousness, irritability, tremor |
| Sleep | Needing more sleep | Insomnia |
| Cycle | Heavy periods | Light or infrequent periods |
| TSH | High | Low |
The same person can move from one picture to the other: some forms of thyroiditis begin with a phase of acceleration before slowing down, and an over-dosed treatment produces signs of hyperthyroidism. In every case, symptoms point the way and the blood test settles it.
What the studies say
Hypothyroidism symptoms: four studies worth knowing.
This research shows how common hypothyroidism is, which signs weigh the most and why the TSH test remains the referee. The full references are at the bottom of the page.
Canaris et al., 2000 · United States
25,862 participants in a health fair in Colorado. 9.5% had a raised TSH, most often without knowing it. People with hypothyroidism reported more symptoms than the others, and the number of associated signs counted for more than any single one.
Carlé et al., 2014 · Denmark
140 patients with newly diagnosed autoimmune hypothyroidism, compared with 560 controls on thirteen symptoms. Tiredness was the most frequently reported sign, and the likelihood of hypothyroidism rose with the number of symptoms present.
Vanderpump et al., 1995 · United Kingdom
Twenty years of follow-up of the people of Whickham. Hypothyroidism appeared each year in 3.5 women per 1,000 and 0.6 men per 1,000. An already raised TSH and the presence of antithyroid antibodies most often foreshadowed this progression.
Hollowell et al., 2002 · United States
The national NHANES III survey, more than 17,000 people aged 12 and over. 4.6% had hypothyroidism: 0.3% overt and 4.3% subclinical. The frequency increased with age and was higher in women.
The tests
TSH, free T4, anti-TPO antibodies: the tests that settle it.
The diagnosis rests on a blood test, prescribed by your GP. The French health authority HAS recommends starting with TSH alone. This hormone, sent by the pituitary gland, tells the thyroid to work: when the gland weakens, TSH rises, often before thyroid hormones fall.
TSH
The first test. When high, it signals a thyroid that is struggling to keep up. When normal, it effectively rules out hypothyroidism.
Free T4
Requested if TSH is high. Low: overt hypothyroidism. Normal: subclinical hypothyroidism.
Anti-TPO antibodies
They look for an autoimmune origin. Their presence points towards Hashimoto's thyroiditis.
A T3 test adds nothing to the diagnosis of hypothyroidism. A neck ultrasound is not routine: it is requested when the doctor feels a nodule or an enlarged gland on examination.
If tiredness dominates, the same blood test can explore the other common causes: blood count, ferritin, vitamin B12, vitamin D, blood sugar. In the cold season, our article on winter fatigue and vitamins goes through these benchmarks. Once levothyroxine treatment has started, TSH is rechecked after 6 to 8 weeks, the time it takes to stabilise.
When to see a doctor
Signs of hypothyroidism: when should you see a doctor?
Hypothyroidism is simple to diagnose and responds well to treatment. The first appointment is with your GP. Note down your symptoms, when they began, your family history and a list of what you take: medicines, supplements, iodine-rich products.
Book an appointment if:
- unusual tiredness has lasted several weeks, with feeling the cold, constipation or dry skin;
- you are gaining weight without any change in diet, or your face looks puffy;
- your periods change noticeably, or a plan to become pregnant is taking time;
- you are pregnant, or have just given birth, and the tiredness or your mood worries you;
- a lump appears in your neck, your voice stays hoarse or you have trouble swallowing;
- lasting sadness or a loss of motivation sets in;
- a relative has a thyroid disease or an autoimmune disease, and you recognise several signs from the table.
Extreme drowsiness, confusion or an abnormally cold body in an older person, or in someone with known hypothyroidism, warrants a call to 112. If you are having dark thoughts, call 116 123, a free helpline you can reach 24 hours a day.
Day to day
Living with hypothyroidism: energy, sleep, diet.
Once the diagnosis is made, levothyroxine replaces the missing hormone. Symptoms recede over a few weeks to a few months, as the dose finds its setting. Around the treatment, the day is built on a few simple markers.
On waking
The tablet on an empty stomach, with a glass of water, at least thirty minutes before breakfast and coffee. Then daylight, to set the body clock.
At breakfast
Protein and a proper meal: eggs, dairy, wholemeal bread, fruit. This is the time for supplements, once the tablet has been taken.
During the day
Twenty to thirty minutes of walking, broken up if need be. Breaks before exhaustion sets in, meals at regular times.
In the evening
A regular bedtime and seven to nine hours of sleep, the amount an adult needs.
On your plate, the thyroid needs iodine: fish, dairy, eggs and iodised salt supply enough in a varied diet. Fibre, water and movement help digestion. When tiredness pushes you towards snacking, complete meals space out the cravings: our guide to quitting sugar gives the method. Ask your doctor before taking any iodine or seaweed supplement, which act directly on the gland.
Our formula
For everyday tiredness: our Energy formula.
Your treatment remains the foundation. Around it, for everyday tiredness, we have designed Energy: cordyceps, maca, ginger and vitamin C, which contributes to the reduction of tiredness and fatigue. A capsule formula, caffeine-free, that slips into the morning routine described above: the tablet on an empty stomach first, the capsule at breakfast afterwards. Our file on the benefits of cordyceps presents the mushroom, its uses and the studies devoted to it.
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Thyroid and fatigue
Why fatigue sometimes persists on treatment, the five leads to check with your doctor, taking the tablet correctly and a 21-day plan.
Read the guide →Food supplement, to be used as part of a varied and balanced diet and a healthy lifestyle. If you are on thyroid treatment, talk to your doctor before starting a supplement.
Your questions
Hypothyroidism and symptoms: your questions.
What are the symptoms of hypothyroidism?
Hypothyroidism symptoms reflect a general slowing down: tiredness from the moment you wake, feeling the cold, moderate weight gain, dry skin, hair loss, constipation, a slow pulse, low mood, memory problems and heavier periods. They develop slowly, over several months. A TSH test, on a simple blood sample, confirms the diagnosis.
How can you tell whether you have hypothyroidism or hyperthyroidism?
Symptoms point the way: feeling the cold, slowness, weight gain and constipation in hypothyroidism; palpitations, heat, weight loss and nervousness in hyperthyroidism. The blood test settles it: a high TSH means hypothyroidism, a low TSH means hyperthyroidism. Free T4 then shows how marked it is.
What are the signs of Hashimoto's disease?
Hashimoto's disease stays silent for a long time. It then shows up as the signs of hypothyroidism: tiredness, feeling the cold, weight gain, dry skin, constipation, sometimes a neck swollen by a firm, painless goitre. The diagnosis rests on a high TSH and the presence of anti-TPO antibodies in the blood.
At what age can you have thyroid problems?
At any age. Congenital hypothyroidism is screened for in every newborn in France, and Hashimoto's disease most often appears in adulthood. The frequency of hypothyroidism then rises with age, especially in women. Pregnancy, the period after childbirth and the menopause are times when a TSH test is often worth discussing.
Can thyroid problems cause brain fog?
Yes. Slowness, forgetfulness, difficulty concentrating and finding words are common signs of hypothyroidism. They generally ease once treatment is well balanced. If they persist with a normal TSH, sleep, iron, vitamin B12 and mood are worth checking with your doctor.
Can hypothyroidism cause cravings?
Hypothyroidism tends to come with a lower appetite, with moderate weight gain linked to the slower metabolism and water retention. Cravings more often come from tiredness and lack of sleep, which push you towards sugar. Regular meals, with protein at breakfast, help space them out.
What are the symptoms of hypothyroidism in women?
On top of the general signs, tiredness, feeling the cold, weight gain, dry skin and constipation, women have signs of their own: heavier or irregular periods, a lower libido, sometimes difficulty conceiving. Hypothyroidism is markedly more common in women, particularly after childbirth and from the age of fifty.
What is subclinical hypothyroidism?
It is early or mild hypothyroidism: TSH is slightly high, but free T4 remains normal. Symptoms are mild or absent. The doctor confirms the result with a second test, looks for anti-TPO antibodies, then chooses between monitoring and treatment depending on the TSH level, age and circumstances, notably a plan to become pregnant.
Sources
- Haute Autorité de santé (2023). Management of hypothyroidism in adults. Good practice guideline.
- Agence nationale de sécurité du médicament (2017). Levothyrox: about 3 million patients treated with levothyroxine in France. Patient leaflet (taken on an empty stomach, before breakfast).
- Chaker L., Bianco A. C., Jonklaas J., Peeters R. P. (2017). Hypothyroidism. The Lancet, 390(10101), 1550-1562.
- Canaris G. J., Manowitz N. R., Mayor G., Ridgway E. C. (2000). The Colorado thyroid disease prevalence study. Archives of Internal Medicine, 160(4), 526-534.
- Carlé A. et al. (2014). Hypothyroid symptoms and the likelihood of overt thyroid failure: a population-based case-control study. European Journal of Endocrinology, 171(5), 593-602.
- Vanderpump M. P. J. et al. (1995). The incidence of thyroid disorders in the community: a twenty-year follow-up of the Whickham Survey. Clinical Endocrinology, 43(1), 55-68.
- Hollowell J. G. et al. (2002). Serum TSH, T4, and thyroid antibodies in the United States population (1988 to 1994): NHANES III. The Journal of Clinical Endocrinology & Metabolism, 87(2), 489-499.
- Pearce S. H. S. et al. (2013). 2013 ETA guideline: management of subclinical hypothyroidism. European Thyroid Journal, 2(4), 215-228.
- Jonklaas J. et al. (2014). Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid, 24(12), 1670-1751.
- Alexander E. K. et al. (2017). 2017 Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and the postpartum. Thyroid, 27(3), 315-389.
- Hirshkowitz M. et al. (2015). National Sleep Foundation's sleep time duration recommendations. Sleep Health, 1(1), 40-43.
- Commission Regulation (EU) No 432/2012: authorised health claims (vitamin C).
Keep reading
Further reading.
Now that the symptoms are identified, what follows plays out over time. Our guide thyroid and fatigue covers the treatment, taking the tablet and the 21-day plan; the articles below complete each sign in the table.
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