What might a high TSH result mean? Your thyroid health and next steps

Are you feeling constantly tired? Gaining or losing weight without explanation? Or finding it hard to concentrate, no matter how much rest you get?

It’s easy to put these changes down to stress, ageing, or the demands of everyday life, and often, that’s true. But sometimes the underlying cause can be your thyroid.

The thyroid is a small gland in your neck, but it plays a significant role in how your body functions. It produces hormones that regulate your metabolism, influence your energy levels, and even affect your mood. When the thyroid slows down or struggles, the effects ripple across your whole body.

One of the main ways to check how well your thyroid is working is by measuring your TSH (thyroid-stimulating hormone). If your thyroid isn’t producing enough hormones, TSH levels usually rise as your body tries to give it a boost. That’s why a high TSH result is often an early sign of hypothyroidism, meaning an underactive thyroid.

According to NICE, around 1–2% of people in the UK live with hypothyroidism. Left untreated, it can affect energy, weight, mood, and overall well-being.

In this article, we explain what TSH is, why a high result matters, and how home testing can help you take charge of your health.

Questions we’ll answer in this blog:

• What is TSH, and why does it matter for your health?

• What are the symptoms of low thyroid function?
  

• What are the benefits of an at-home test?
  

• How does at-home thyroid testing work?
  

• Who is at risk of a low thyroid?
  

• Common thyroid questions
  

• What lifestyle tips can support thyroid and overall wellness?

What is TSH, and why does it matter?

As we’ve touched upon, TSH stands for Thyroid-stimulating Hormone. It’s one of the most important markers in a thyroid function test. Rather than being a thyroid hormone itself, it acts like a feedback signal that shows whether your thyroid is keeping up with your body’s needs. 

The thyroid’s main job is to release hormones that help regulate how your body uses energy. It produces thyroxine (T4), which is mostly converted in the liver and other organs into triiodothyronine (T3), the active hormone that drives your metabolism. 

The thyroid also makes a smaller hormone called calcitonin, which helps regulate calcium in the blood and supports strong, healthy bones. These hormones affect everything from how fast your body burns calories to how well your heart, muscles, and brain function.

A high TSH result often suggests your thyroid is underactive and not producing enough hormone. As thyroid hormones affect everything from your metabolism to your mood, even slight imbalances can have a big impact.

The challenge with an underactive thyroid is that symptoms often develop slowly and can easily be mistaken for other health problems.

What are the symptoms of low thyroid function?

The British Thyroid Foundation suggests that some common signs your thyroid might be underactive include:

• Ongoing tiredness or low energy
  

• Weight gain or difficulty losing weight
  

• Dry skin or brittle nails
  

• Feeling cold all the time
  

• Brain fog or trouble concentrating
  

• Mood changes, such as low mood or irritability
  

• Irregular periods or fertility issues
  

If these symptoms sound familiar, it may be worth checking your TSH levels.

What are the benefits of an at-home test?

If you're experiencing any of the symptoms above, an at-home test is a convenient way to check your TSH level. Our Underactive Thyroid (TSH) Rapid Test Kit provides a fast way to get an initial reading.

These tests are designed to be simple to use and give precise results within minutes. 

These tests use the same calibre of technology trusted by healthcare professionals. They undergo strict certification processes, giving you confidence in your results.

It’s about empowering yourself and taking control with clear, accessible information.

How does an at-home test work?

An at-home thyroid test lets you check your TSH levels from a simple finger-prick blood sample, all in the comfort of your own home. 

Once the sample is placed on the test cassette and mixed with a buffer solution, it naturally moves along the strip by capillary action, the same process that allows a paper towel to soak up liquid. The strip contains special antibodies that react to TSH in the blood.

If TSH is present above the detection threshold (5 μIU/mL), a coloured line will appear in the test window, alongside a control line that confirms the test has worked correctly. The whole process takes around 10 minutes.

This kind of rapid test is a screening tool, a quick and private way to get an initial sense of your thyroid function. However, it doesn’t replace a full thyroid panel, and any concerns or abnormal results should always be followed up with a healthcare professional.

Who is at risk of low thyroid function?

Before you test, it's worth trying to work out whether you're in a high-risk group for hypothyroidism. 

According to the NHS, groups who are more likely to develop hypothyroidism include:

• Those with a family history of thyroid conditions

• Having previously undergone surgery or radiotherapy in the neck region

• Individuals suffering from iodine deficiency 

• Those taking medication treatment for hyperthyroidism. 

For individuals at risk, regular thyroid monitoring can be a key step in identifying issues early.

Answers to common thyroid questions

Now that you know who might be more vulnerable, how to spot the signs, and when to test, here are some answers to the questions people often ask about thyroid health:

Can TSH levels affect my energy and mood?

Yes. TSH regulates your thyroid, which in turn influences metabolism and energy. When thyroid hormone is low, TSH rises, often leaving people feeling tired, sluggish, or low in mood.

TSH, or thyroid-stimulating hormone, helps control how much thyroxine (T4) and triiodothyronine (T3) your thyroid produces. These hormones act on nearly every tissue in the body, influencing how quickly cells use energy, how sensitive you are to other hormones, and even how your brain functions.

When your thyroid is underactive, TSH increases in an effort to stimulate more hormone production. With less T3 and T4 available, metabolism slows. This can lead to fatigue, low energy, difficulty concentrating, unexplained weight gain, sensitivity to cold, or what many describe as ‘brain fog’. In a study of around 1,200 individuals suffering from hypothyroidism, 89% experienced ‘abnormal’ levels of fatigue.

That’s why monitoring TSH is such an important window into your overall energy, mood, and well-being.

Can stress affect thyroid health?

Yes. Stress can disrupt hormone balance in the body and interfere with how well the thyroid functions. It doesn’t directly cause hypothyroidism, but it can make symptoms like fatigue, low mood, or brain fog worse.

When you experience long-term stress, your body produces higher levels of cortisol, often called the ‘stress hormone’. Elevated cortisol can affect how the thyroid gland works by:

• Slowing the conversion of thyroxine (T4) into its active form, triiodothyronine (T3)

• Making body tissues less responsive to thyroid hormones

• Placing extra strain on the immune system, which is relevant in autoimmune thyroid conditions like Hashimoto’s

As a result, people with thyroid issues may notice that stress worsens common symptoms such as tiredness, difficulty concentrating, or mood changes.

Does a high TSH result always mean I have hypothyroidism?

No. A single high TSH result doesn’t automatically mean you have hypothyroidism. It indicates your thyroid may not be working optimally, but it isn’t enough on its own to confirm a diagnosis.

TSH levels can fluctuate for a variety of reasons besides an underactive thyroid. These include:

• Stress or illness

• Certain medications (for example, some antidepressants or steroids)

• Natural fluctuations depending on the time of day the blood was taken

Because of these factors, doctors usually look at TSH alongside other thyroid hormone measurements to get a complete picture of thyroid function.

In short, a high TSH is a signal to investigate further, not a definitive diagnosis. If your test comes back elevated, the next step is to discuss your results with a healthcare provider, who can recommend additional tests or monitoring to determine whether treatment is needed.

How to support your overall well-being and thyroid health

Regardless of your thyroid function test results, focusing on overall well-being is always beneficial. 

Making healthy lifestyle choices helps your body function more effectively. It can support both emotional and physical well-being.

Here are some areas to consider:

Eat a healthy, balanced diet

Your thyroid gland benefits from essential nutrients to function effectively. Ensuring a balanced diet rich in vitamins and minerals is a cornerstone of general wellness.

The British Thyroid Foundation indicates that key nutrients supporting healthy thyroid function include iodine, selenium, and zinc. You can achieve a healthy level through a varied diet that includes foods such as seafood, lean proteins, nuts, seeds, and whole grains.

Exercise regularly

The NHS advises that physical activity is a powerful tool for supporting overall vitality. It can boost your mood and regulate energy levels.

The activities you choose don't have to be intense. Finding activities you genuinely enjoy and can do consistently is key.

Whether it's brisk walking, swimming, cycling, dancing, or strength training, being active supports circulation and metabolic health.

Focus on quality sleep

Sleep is a critical time for your body to rest, repair, and regulate many internal processes. A lack of sleep disrupts hormonal balance, affecting your energy and mood.  

Aim for consistent sleep patterns and create a calming bedtime routine to support restful sleep.

Key takeaways

• TSH is a key thyroid regulator: High TSH can indicate that your thyroid may not be producing enough hormones.
  

• Symptoms can develop gradually: Fatigue, weight changes, mood shifts, and low energy can all signal low thyroid function.
  

• Certain groups are at higher risk: Family history, previous neck surgery or radiotherapy, iodine deficiency, and hyperthyroidism treatment increase your likelihood.
  

• At-home testing is a proactive first step: Rapid test kits provide convenient, instant and reliable initial insights into your thyroid health.
  

• Lifestyle matters: Balanced nutrition, regular exercise, and quality sleep support thyroid function and overall well-being.

Empowering your health journey

Taking a thyroid function test provides valuable insights into your body.

A high TSH result is not necessarily a cause for alarm, but rather an invitation to pay closer attention and gather more information. 

At Rezure, we believe that understanding your health should be straightforward and accessible. Taking steps to confirm results and discussing them with a healthcare professional allows you to approach your health proactively and make informed decisions.

Could your symptoms be thyroid-related? Try our Underactive Thyroid Test today. Get fast, accurate results from the privacy of your home.