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What Is the Normal Thyroid TSH Level?

What Is the Normal Thyroid TSH Level?

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What Is the Normal Thyroid TSH Level?

The normal level of Thyroid Stimulating Hormone (TSH) expected to be found is between 0.45 and 4.5 milliunits per litre of blood, although many factors can affect your thyroid hormones temporarily as well as permanently. You can test your TSH levels with an Instant Thyroid Test, but what are you looking for and when do you need to take a thyroid test? Keep reading to find out.

What is the Thyroid and What Does it Do?

The thyroid is a small, butterfly-shaped gland in the throat, in front of the trachea, that changes the way our bodies produce fat, by controlling our metabolism. Thyroid Stimulating Hormone is produced by the pituitary gland to stimulate the thyroid into producing more thyroid hormones Thyroxine and Triiodothyronine, known as T4 and T3. When more thyroid hormones are needed, the pituitary gland produces more TSH to see more T4 and T3 in the blood, if there is too much of the thyroid hormones in the blood, the pituitary gland stops producing TSH until it’s needed again.

What Is the Normal Thyroid TSH Level?

Why Do TSH Levels Change?

Our TSH levels fluctuate throughout our lives, especially for women who see many thyroid changes through their menstrual cycle as well as having increased chances of developing an underactive thyroid compared to men. However, there are other factors that change TSH levels as well, including age and health conditions.


As we get older, our thyroids change and so do our TSH levels.

These are the normal TSH levels per age range:

  • 18 - 50: 0.5 - 4.1 mU/L
  • 50 - 70: 0.5 - 4.5 mU/L
  • 70 - 90: 0.4 - 5.2 mU/L

Having slightly higher TSH levels as you get older is not a cause for concern as it’s a normal part of life, however, even as you age, if your TSH levels greatly exceed or fall lower than the normal ranges, you should visit your doctor for a Thyroid check.

Children under 18 have even more fluctuating TSH levels, so it’s even more important to be wary of Thyroid symptoms as soon as they develop, as children’s normal TSH range differs from that of over 18s, especially as TSH levels decrease towards adulthood before steadily rising again once they reach 18.

Why Do TSH Levels Change?

Menstruation and Pregnancy

The thyroid gland has a direct effect on our reproductive systems in both men and women, however, women are more susceptible to developing thyroid conditions than men, as well as being prone to experience abnormal TSH levels during menstruation, pregnancy and after menopause.

Women with thyroid disease also experience irregular periods, problems with fertility and increased chances of miscarriage, with an underactive thyroid also causing heavy and painful periods, and an overactive thyroid causing lighter periods. With irregular periods, ovulation is also irregular which makes it more difficult to get pregnant, however, if you’re trying for a baby, you can take an instant ovulation test to find out straight away if you’re ovulating.

Other health conditions affect fertility, such as PCOS which also causes irregular menstrual cycles, so if you have irregular, heavy, light or painful periods, or you’re struggling to get pregnant, you should visit your doctor.

Health Conditions

Thyroid dysfunction can be caused by other illnesses, so it's important that your doctor does thorough thyroid testing if you present with symptoms. If you have a family history of thyroid disease, then it’s even more important to have regular testing and visit your doctor as soon as you develop any symptoms of an overactive or underactive thyroid or feel lumps, known as thyroid nodules, in your throat.

The most common cause of an overactive thyroid is Graves’ disease, an auto-immune disease that specifically attacks the thyroid causing it to overproduce T3 and T4. Similarly, Hashimoto's disease is a common cause of an underactive thyroid, mistakenly attacking the thyroid in an attempt to fight off bacteria and viruses in the system and causing it to function poorly.

Other autoimmune diseases affect different parts of the body, such as Lupus which attacks joints, the skin and organs, vitiligo attacking the skin pigment, and Type 1 diabetes which attacks the insulin-producing cells in the pancreas. While they don’t directly affect the thyroid, if your body is attacking itself, it may have a knock-on effect on thyroid function, so if these illnesses run in your family, it’s best to have regular thyroid checks.

Health Conditions


Having a healthy diet is important to have a healthy life, so whether you have a thyroid problem diagnosis or not, you should be eating a balanced diet for the sake of your physical and mental health.

If you’re worried about your thyroid, however, you should know that there is no specific diet that helps thyroid disease, or foods that can control your TSH levels. People with hypothyroidism or hyperthyroidism will be given a treatment plan by their medical practitioner which will usually include thyroid hormone replacement therapy i.e. taking medication such as levothyroxine to replace thyroxine (T4), or undergoing radioactive iodine treatment.

That said, since thyroid disease can cause weight changes, you may need to alter your diet if you notice a significant change in your weight, although this should be done with caution and under medical guidance.

Thyroid disease also causes fats to clog up the arteries in our bodies which is why we see an increased risk of heart conditions in hyperthyroidism patients, so people with thyroid disease should avoid saturated fats altogether, and limit their intake of other high-cholesterol or high-unsaturated fat products.

Saturated fats can be found in:

  • Dairy products
  • Animal fats
  • Products made with butter, ghee or lard
  • Coconut oil
  • Palm oil

Reducing intake of saturated fats is crucial for the heart health of people with thyroid disease, so they should replace the animal fats in their diets by eating more vegan and vegetarian dishes as well as choosing healthy alternatives like lean beef mince rather than full-fat.


How Do You Test TSH Levels?

Staying on top of your TSH levels is the best way to monitor your thyroid function, and can be especially helpful for people who have just begun a course of thyroid medication and need to see how well the medicine is working. The best way to check your TSH levels is by taking an instant thyroid test.

After you’ve chosen the best thyroid test to take, from reading excellent reviews to learning about the company’s mission, you can take instant thyroid tests at home by using the enclosed lancet to prick your finger and collect your blood sample in a small plastic tube, which you can then send off to the medical laboratory.

If the company has an expert management software for their medical laboratory like us, then you’ll receive your TSH results swiftly and securely via email, so you know exactly how much TSH your body is producing.

What to Do with Thyroid Test Results

When you receive your test results, you can have a rough idea of whether your TSH levels are within the normal range for your age group from the guidance given above, however, it’s best to take your thyroid test results to your doctor to have them interpreted by a medical expert who is aware of your and your family’s medical history. This way, they’re best equipped to interpret your thyroid results and suggest the best course of action to take regarding treating your thyroid.

Best Thyroid Tests to Take at Home

As levels of thyroid-stimulating hormone can fluctuate greatly and increase as we age and our bodies change, it’s important to have quick access to medical tests so you can monitor your thyroid levels without having to wait for doctors’ appointments.

Our instant thyroid test is simple and convenient, allowing you to test your TSH levels at home and get fast results. Order yours today, or visit one of our test centres for other medical tests.