How to take your thyroid tablet (levothyroxine) the right way

Levothyroxine (also called thyroxine or T4) is one of the most prescribed medicines in India, sold under many brand names. It replaces the hormone your thyroid cannot make. It is simple and very effective, but it is also fussy about how it is taken. Many cases of “my TSH will not settle” turn out to be about timing, tea, or iron tablets rather than the wrong strength.

This page is about how to take it. How much to take is decided only by your doctor, based on your TSH and your health. Please do not change your strength on your own.

Why does timing matter so much?

Levothyroxine is absorbed in the small intestine, and only part of each tablet gets into the blood even in ideal conditions. Food, drinks and other medicines in the stomach can bind to it or change the acidity it needs, so less is absorbed. If the amount absorbed changes from day to day, your TSH swings up and down, and your doctor may keep changing the strength without fixing the real problem.

What is the usual advice on an empty stomach?

Doctors usually advise:

• Swallowing the tablet with plain water, first thing in the morning, on an empty stomach.
• Waiting 30 to 60 minutes before breakfast. A study comparing timings found that TSH was lower and steadier when the tablet was taken an hour before breakfast than when it was taken with food.
• Keeping this the same every day.

For people who find mornings impossible, a bedtime routine is an accepted alternative, as long as it is at least three to four hours after the last meal. In a Dutch trial, taking the tablet at bedtime worked at least as well as in the morning. If you want to switch to bedtime, tell your doctor first, because your TSH will need to be rechecked.

Can I have tea or coffee after my thyroid tablet?

Not immediately. Coffee has been shown to reduce how much levothyroxine is absorbed when the two are taken close together. Tea and milk are likely to have a similar effect. The usual advice is to wait at least 30 to 60 minutes after the tablet before your morning chai or coffee. For more detail, see can I take my thyroid tablet with tea.

Which medicines and foods interfere?

Some things need a much longer gap, usually about four hours:

• Calcium tablets, and calcium with vitamin D
• Iron tablets, very commonly given to Indian women and in pregnancy
• Antacids and gels containing aluminium or magnesium
• Multivitamins and minerals
• Sucralfate and cholesterol-binding resins

Others work differently:

• Acid-reducing medicines such as pantoprazole, omeprazole and rabeprazole may reduce absorption over time. Tell your doctor if you take them daily.
• Soya products, very high-fibre meals and some herbal powders can reduce absorption.
• Some epilepsy medicines and rifampicin speed up the breakdown of thyroid hormone.
• Oestrogen, including the contraceptive pill and HRT, can increase the amount of thyroid hormone you need.

A simple routine many people follow: thyroid tablet on waking, breakfast and tea later, and calcium or iron with lunch or dinner. Your doctor can help you fit it around your other medicines.

What if I keep forgetting?

Consistency matters most. A few ideas:

• Keep the strip next to your toothbrush or water bottle.
• Set a phone alarm.
• Use a weekly calendar or tick box.

Levothyroxine stays in the body for a long time, so an occasional missed day is not dangerous. Ask your doctor what they want you to do when you miss one, and do not guess.

Does the brand matter?

All levothyroxine contains the same hormone, but small differences in how tablets are made can change how much is absorbed. For most people this does not matter much. For some, especially in pregnancy, after thyroid cancer, in older people or in those with heart disease, a brand change can shift TSH.

Practical points:

• Try to stay on the same brand and strength, and check the strip at the chemist.
• If you are switched to another brand or a generic, your doctor may suggest a TSH test after about six to eight weeks.
• Do not split or crush tablets unless your doctor or pharmacist says it is fine.

How should I store levothyroxine?

Thyroid tablets lose strength when exposed to heat, humidity and light, which is a real issue in Indian summers and monsoons.

• Keep tablets in their original strip or bottle, closed tightly.
• Store in a cool, dry place, away from the kitchen stove and bathroom.
• Do not keep them in a hot car or near a window.
• Check the expiry date.

When should TSH be checked?

After any change in strength or brand, TSH is usually checked again after about six to eight weeks, because that is how long it takes to settle. Once stable, many people need a test only once or twice a year. Try to give the sample at a similar time each time. You can make sense of the result with the thyroid report reader.

What if my TSH is still not normal?

If your TSH stays high despite taking the tablet regularly, doctors look at timing, food, other medicines, brand, storage and conditions that affect absorption, such as coeliac disease, low stomach acid or H. pylori infection. Only after these are checked is the strength usually changed. Read more about an underactive thyroid. A small group of people may be offered T3 as well. Read liothyronine (T3) tablets.

What should you ask your doctor?

• What time of day suits my routine best?
• How should I space my tablet from my other medicines?
• Should I stay on one brand?
• When is my next TSH test due?

If you are pregnant or planning a pregnancy, your thyroid needs change early. Read thyroid problems in pregnancy or book a consultation.