The overlooked symptoms of hypothyroidism

You’re tired all the time. Your skin feels dry, your hair’s thinning, and the number on the scale seems to be moving up even though nothing’s changed. It’s easy to chalk it all up to stress, age, or leading a busy life. But these seemingly unrelated symptoms may be connected by a common thread, and it might be your thyroid.

Hypothyroidism, or an underactive thyroid, affects up to 1 in 20 people in the UK.¹ It’s a condition where the thyroid gland doesn’t produce enough of the hormones that keep your body ticking over. These hormones influence everything from your metabolism and mood to your digestion, heart rate, and even fertility.²

And yet, for something so wide-reaching, hypothyroidism often flies under the radar.

When “just tired” might mean something more

The symptoms of hypothyroidism are frustratingly vague.² Fatigue. Feeling the cold more than usual. Weight gain. Constipation. Brain fog. Low mood. Dry skin. Hair loss. These are things many of us live with, often for years, without realising there might be a medical reason.

The thyroid slows down gradually, which means the signs often blend into the background. Many people only get a diagnosis after things have gone on for far too long. Women, in particular, are around 10 times more likely to be affected, and more likely to have their symptoms dismissed as hormonal, menopausal, or mental health-related.^1,3

Blood tests can provide a clearer picture

Because the symptoms are so non-specific, a blood test is the only reliable way to check if your thyroid is working properly. The key markers include:⁴

• TSH (thyroid-stimulating hormone): This hormone tells your thyroid when to produce more hormones. If your thyroid is underactive, TSH levels will usually be high – your body is shouting for more hormone, but the thyroid isn’t keeping up.

• Free T4 (thyroxine): This is one of the main hormones made by the thyroid. Low levels indicate the gland isn’t producing enough.

• Free T3 (triiodothyronine): This is the active form of thyroid hormone, and while it’s not always measured initially, it can help build a fuller picture.

• Thyroid antibodies: These can show whether your hypothyroidism is caused by an autoimmune condition.

Together, these markers help clinicians understand whether your symptoms are related to a thyroid issue and what kind of support you need.

Why early detection matters

Left untreated, hypothyroidism can lead to complications that affect almost every system in your body. It can increase your risk of heart disease, raise cholesterol, slow down digestion, and, in severe cases, lead to something called myxoedema, which is a rare but life-threatening condition.⁵

In pregnancy, untreated hypothyroidism can cause problems for both mother and baby, including preterm birth and developmental issues.⁵

Should you get tested?

If you’re experiencing persistent fatigue, weight gain, low mood, or any of the other common symptoms, a thyroid blood test is a sensible next step. It’s especially worth considering if you have:²

• A family history of thyroid problems

• Another autoimmune condition (like type 1 diabetes or coeliac disease)

• Recently given birth

• Unexplained fertility issues

• A history of neck surgery or radioiodine treatment

The numan take

Hypothyroidism isn’t always easy to spot, but it’s easier to treat than many people realise. If you’ve been brushing off persistent symptoms or just haven’t felt like yourself in a while, it’s worth checking if it could be down to your thyroid.

References 

1. Background information. Org.uk. https://cks.nice.org.uk/topics/hypothyroidism/background-information/prevalence/ [Accessed 26th June 2025].

2. Chaker L, Bianco AC, Jonklaas J, Peeters RP. Hypothyroidism. Lancet. 2017;390(10101): 1550–1562.

3. Women with underactive thyroids are being told they are menopausal or depressed. Women’s Health. https://www.womenshealthmag.com/uk/health/female-health/a60395043/underactive-thyroid-menopausal-depressed/ [Accessed 30th June 2025].

4. Miller GD, Rogers JC, DeGroote SL, Schmitz D. Clinical inquiries: which lab tests are best when you suspect hypothyroidism? The journal of family practice. 2008;57(9): 613–614.

5. Wiersinga WM. Adult hypothyroidism. In: Endotext. South Dartmouth (MA): MDText.com, Inc.; 2000.