• Levothyroxine
  • Levothyroxine


Medication features

  • Underactive thyroid treatment
  • Various strengths available
  • If you have a specific brand request please advise at time of ordering 


Order Levothyroxine Tablets Online

You can request to order Levothyroxine online from our UK registered online doctor and pharmacy service. We ask that you complete an online medical assessment as part of your order. Our doctors will use this assessment to make sure that it is safe and suitable to prescribe for you. 

If your order is approved, a prescription is sent to our online pharmacy team. From here, your medicine will be dispensed and dispatched to your delivery address. Please note, this service is only available for patients who are currently prescribed Levothyroxine on repeat by their GP.

What is Levothyroxine?

Levothyroxine is a medicine that is used to treat an underactive thyroid (hypothyroidism). The active ingredient is Levothyroxine sodium. It is a prescription-only medicine and is not available over the counter. It is a commonly prescribed medicine and is the main medicine used in the treatment of an underactive thyroid. It may also replace thyroid hormone for people who have to have their thyroid completely removed or damaged due to thyroid cancer.

How does Levothyroxine work?

In people with an underactive thyroid gland, the thyroid does not produce enough of the hormone thyroxine. This hormone is essential for normal bodily functions like growth and metabolism. Having lower levels of thyroxine can cause symptoms like tiredness (low energy levels), muscle aches, weight gain, and depression. 

Levothyroxine is a synthetic version of the hormone thyroxine and it works to replace the thyroxine that your thyroid gland isn’t producing. This helps to improve the symptoms of an underactive thyroid.

How to take Levothyroxine

You should take your Levothyroxine tablets exactly as your doctor has told you to. Your doctor will decide the most appropriate Levothyroxine starting dose for you based on a thyroid function blood test. The blood test tells your doctor what your thyroid hormone levels are. The test looks at serum TSH levels and T4 levels in the blood.

At the beginning of treatment, you may need frequent blood tests until your dose is right for you. When your dose is stable, you’ll usually have a blood test every year to monitor your dose.

You should swallow the tablets whole with water and usually your doctor will tell you to take the tablets before breakfast. It is best to take it on an empty stomach because some food or drinks can reduce the absorption of Levothyroxine.

People who take Levothyroxine usually have to take it for life.

Levothyroxine Summary


Take as directed before breakfast on an empty stomach

Type of medicine

Thyroid hormone


Replaces or supplements the thyroxine your thyroid gland is not producing

Available Size

28 - 84 tablets


12.5ug - 100ug

Active Ingredient

Levothyroxine sodium


From £35.99

Side Effects

Can include headaches, nausea, muscle cramps, feeling restless

Levothyroxine Side Effects

Most side effects that happen can happen because the dose is not quite right. Once you and your doctor have found the dose that suits you, most side effects tend to improve. 

The most common side effects are symptoms that are similar to an overactive thyroid. This may happen because the dose you take is too high. These side effects include muscle cramps, headaches, nausea, tremors, weight loss, and feeling restless. If you notice any of these side effects, contact your doctor because your dose may need to be changed.

Some people can have a severe reaction to high levels of thyroxine. If you notice symptoms such as a very high temperature, fast heart rate and confusion, speak to your doctor immediately.

See the patient information leaflet for further information on the side effects.


Hywel McGlinchy, Clinical Pharmacist


Hywel McGlinchy

RoleClinical Pharmacist
Qual.Masters of Pharmacy
AboutHywel started with Simple Online Pharmacy in 2020. He's responsible for helping author and review accurate site content. He also works with our GPs to make sure all aspects of patient safety are covered. 


How long does it take for Levothyroxine to work?

It starts to work immediately to increase your thyroid hormone levels. However, it might take some time for your doctor to find the most appropriate dose for you. It can still take several weeks of Levothyroxine treatment until your symptoms improve and you feel better.

What does Levothyroxine do to the body?

It is used to treat an underactive thyroid. An underactive thyroid doesn’t produce enough of the hormone thyroxine. Levothyroxine is a synthetic version of this hormone and helps to increase thyroxine levels in the body.

Is it better to take Levothyroxine in the morning or at night?

Levothyroxine should be taken in the morning. Ideally, it should be taken on an empty stomach with water around 30 minutes before food or caffeine-containing drinks. It should also be taken 30 minutes before any of your other medication.

Is Levothyroxine taken for life?

Hypothyroidism is usually a lifelong condition. This means that people who are prescribed it are usually prescribed it for life. Once the dose is suitable, you will usually have a blood test once a year to check your thyroxine levels are healthy.

Is 100mcg of Levothyroxine a high dose?

The most suitable dose varies from person to person and depends on their blood test results. The dose can range from around 25mcg a day to 200mcg a day. Your doctor will decide the most appropriate dose for you based on your blood test.

Can I take Levothyroxine with my other medications?

Some medicines can interact with Levothyroxine and they shouldn’t be taken together. Other medicines are okay to take with Levothyroxine but should be taken at different times. See the patient information leaflet for information on interacting medicines and speak to your pharmacist for advice if you are unsure.

Can I buy Levothyroxine over the counter?

Levothyroxine, in the UK, is not available to buy over the counter because it is a prescription-only medicine. You can request to order it from our UK registered online doctor and pharmacy service. You must complete an online assessment as part of your order. Buying levothyroxine online allows our doctors to check it is safe and suitable to prescribe for you. If your order is approved, our online pharmacy team will dispense and dispatch the medicine to your delivery address.


Info Leaflet

Before taking any medication, it is important to read the Patient Information Leaflet: 


Warnings & Precautions

Other conditions and Levothyroxine

Certain people should not take Levothyroxine. This includes people who have had an allergic reaction to it (or any of the ingredients in the tablets) in the past. It is not suitable for anyone who has an overactive thyroid (hyperthyroidism). People with adrenal gland problems should also not take Levothyroxine. 

The patient information leaflet contains more information. If you are unsure, speak to your doctor or pharmacist for advice.

Interactions with other medicines

A number of medicines can affect the way Levothyroxine works or vice versa. Common interacting medicines include anti-epileptic medicines, beta-blockers (for heart problems), certain medicines for high blood pressure, and corticosteroids. Some interacting medicines can still be taken with Levothyroxine but your dose may need to be adjusted.

Some people worry about hair loss as a result of this medication. The hair loss is usually a result of an underactive thyroid but the hair loss can continue for a while after starting the tablets. Hair usually regrows after you have treatment with Levothyroxine but it can take several months.

See the patient information leaflet or speak to your pharmacist if you are worried or unsure about drug interactions.

Content Reviewed: 24/12/21

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Medication Simple Online Pharmacy
12.5mcg x28 £35.99
12.5mcg x56 £55.99
25mcg x28 £35.99
25mcg x56 £45.99
50mcg x28 £35.99
50mcg x56 £45.99
75mcg x28 £35.99
75mcg x56 £45.99
100mcg x28 £35.99
100mcg x56 £45.99
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