Levothyroxine in Australia: What It's For, Eltroxin vs Oroxine, and How to Take It

Levothyroxine is a synthetic version of thyroxine (T4), the main hormone your thyroid makes, and it is chemically identical to it. In Australia it is the standard tablet for an underactive thyroid, including Hashimoto's, and for life after a thyroidectomy. Eltroxin and Oroxine are two of several brands. They contain the same medicine but are not always swapped dose for dose. You take it with water on an empty stomach, at least 30 and preferably 60 minutes before food, at the same time each day.

If you have just been handed a script, or you have taken it for years and still have questions, this is the plain guide: what it is for, the Australian brands, what it costs on the PBS, how to take it, and how it is checked.

When to get help straight away

The Australian leaflet lists chest pain, an irregular heartbeat, shortness of breath, tremor and allergic reactions such as a skin rash as serious side effects. If you notice any of these, call your doctor straight away or go to your nearest emergency department. If chest pain is severe, getting worse or has lasted 10 minutes, healthdirect advises calling 000 for an ambulance.

If you, or a child, may have taken too much, phone the Poisons Information Centre on 13 11 26 or go to the emergency department, even if there are no signs of a problem yet.

What is levothyroxine?

Your thyroid makes two main hormones, T4 and T3. Most of what it releases is T4, also called thyroxine, and your body converts some of it to T3 as needed. Levothyroxine is T4 made in a laboratory. The American Thyroid Association describes it as identical to the molecule the body produces, and American labelling calls synthetic T4 chemically identical to the hormone from the human thyroid gland.

That is why the names overlap. "Thyroxine", "levothyroxine", "L-thyroxine" and "T4" all refer to the same hormone, and Australian product information uses "thyroxine" and "levothyroxine sodium" interchangeably. If your doctor says thyroxine and your box says levothyroxine, it is the same medicine.

It is a prescription-only medicine in Australia, so you need a script from your doctor at any pharmacy, including the big chains and online pharmacies. It comes as a small tablet you swallow once a day.

What is levothyroxine used for?

The Australian product information lists two uses: managing a confirmed lack of thyroid hormone, and lowering TSH (the signal from your pituitary gland) as part of managing certain thyroid cancers.

• Underactive thyroid (hypothyroidism): the most common cause in Australia is Hashimoto's, an autoimmune condition, according to healthdirect.
• After a thyroidectomy: once the whole thyroid is removed, levothyroxine replaces all of the hormone it used to make. After half a thyroidectomy, some people need it and some don't.
• After radioactive iodine: treatment for an overactive thyroid often leaves the gland underactive, and levothyroxine then replaces what is missing.
• After some thyroid cancers: specialists sometimes set the dose to keep TSH lower than usual for a period. The 2025 American Thyroid Association guideline no longer suggests long-term TSH suppression for most low or intermediate risk cancers without recurrence, so this is an individual decision your specialist makes.

What it is not for matters too. Every Australian label says levothyroxine should not be used for weight loss, and that larger doses can cause serious harm. The American Thyroid Association strongly recommends against prescribing it for tiredness or other general symptoms when thyroid tests are normal. If you feel unwell but your results are in range, that is worth investigating with your GP, but extra thyroid hormone is not the answer.

Levothyroxine brands in Australia: Eltroxin, Oroxine and the rest

Nine brands are listed on the PBS at the time of writing: Oroxine, Eutroxsig, Eltroxin, Levothox, APO-Levothyroxine, Levothyroxine Lup, Levothyroxine Sandoz, Levoxine and Thyrox. They all contain levothyroxine sodium, but the PBS places them in groups, and Eltroxin and Levothox are absorbed slightly differently from Oroxine and Eutroxsig. Every Australian leaflet says not to switch or interchange brands unless your doctor advises it.

In practice that means knowing your brand name and checking the box each time you collect it. Our guide to switching levothyroxine brands in Australia covers the two groups, how pharmacy substitution works and what to do if your brand changes.

Strengths. The PBS-listed tablets come in 50, 75, 100 and 200 microgram strengths, and Eltroxin is also listed at 125 micrograms. Some brands make other strengths, such as 25 micrograms, which are not on the PBS. Your doctor may combine whole tablets to reach your dose.

Storage. This is where Australian brands genuinely differ. Oroxine and Eutroxsig are stored in the fridge (2 to 8°C, not frozen) in their original blister strips. Their leaflets allow one strip out of the fridge, below 25°C, for up to 14 days, and Webster packs for 14 days below 25°C. The other brands are stored below 25°C. Whatever you take, keep it out of the bathroom and the car, and check the storage line on your own leaflet.

What levothyroxine costs on the PBS

All the brands above are PBS-listed. Each script is for a box of 200 tablets with one repeat. Under the 2026 PBS amounts, you pay no more than $25 for a box without a concession card, or $7.70 with one. Some brands, Oroxine among them, carry a small extra brand charge of about a dollar. Your pharmacist can tell you exactly what you'll pay.

How to take levothyroxine

The Australian leaflets all give the same instructions:

• First thing in the morning, on an empty stomach.
• Swallow it with a glass of water.
• Wait before eating: at least 30 minutes, and preferably 60 minutes, before any food or other medicines.
• Keep it consistent. The same routine each day helps keep your results steady.

Coffee counts as food here, and it can reduce how much of the tablet you absorb if it comes too soon. Our guide to coffee and levothyroxine explains how long to wait.

Calcium, iron and other mineral supplements need a longer gap. The Australian product information says to separate them by several hours, and American labelling says at least 4 hours. In small studies, taking calcium or iron at the same time as the tablet raised TSH, and with iron some people felt more symptoms. Breakfast itself only needs the 30 to 60 minutes. Our guide to supplements and levothyroxine timing goes through each one.

Night-time dosing is something some doctors suggest when mornings don't work. The American Thyroid Association lists bedtime, at least three hours after the evening meal, as an alternative, as long as it is consistent. In a Dutch trial, bedtime dosing gave slightly better results than morning; an American trial found the fasting morning dose gave the lowest and least variable results. Because changing your routine can shift your results, make that change with your doctor, and expect a test afterwards.

How levothyroxine is monitored

Levothyroxine works slowly. The Australian product information says its peak effect after starting comes at about three to four weeks, and levels take about six weeks to settle. So your first thyroid test usually comes about six weeks after you start or change a dose, with some guidance giving a range of four to eight weeks. Once your results are where your doctor wants them, the American Thyroid Association suggests a test four to six months later, then yearly.

It is common for the first dose to need adjusting. Your doctor may also look at your dose again if your weight changes a lot, as you get older, if you start certain medicines, or if you become pregnant. Our guide to how long a levothyroxine dose change takes explains the timeline.

How you feel can lag behind the numbers, and some people still don't feel right once their results are in range. That is a recognised situation, not a personal failing. Our guide to why levothyroxine doesn't always fix everything covers what to raise with your doctor.

Side effects are usually dose signs

Because levothyroxine is the same hormone your body makes, most side effects are signs that the dose is too high, such as a racing heart, shakiness, feeling hot and sweaty, poor sleep or anxiety. healthdirect says side effects are rare when you are on the correct dose. A dose that is too low tends to feel like the underactive thyroid itself. Don't adjust your own dose in either case: talk to your doctor and get a test. Our guide to levothyroxine side effects and dose signs sets out both lists.

Is levothyroxine for life?

For many people, yes. healthdirect says that in most cases of hypothyroidism you will need it for the rest of your life, and after a total thyroidectomy there is no gland left to take over. Hashimoto's is usually long-term too. The tablet doesn't switch your thyroid off for good; the underlying condition decides how long you need it. Our guide to whether thyroid medication stops your thyroid working explains why. Never stop it on your own; any change to your treatment belongs with your doctor.

Same tablet, same time, water only, then wait. Know your brand name, and check the box every time you collect it.

Frequently asked questions

Is Eltroxin the same as Oroxine?

Both contain levothyroxine, but they are not interchangeable dose for dose. Eltroxin is absorbed slightly differently from Oroxine and Eutroxsig, and Oroxine is stored in the fridge while Eltroxin is kept below 25°C. Only change brands if your doctor advises it, and expect a thyroid test about six weeks later.

Is thyroxine the same as levothyroxine?

Yes. Thyroxine, or T4, is the hormone your thyroid makes, and levothyroxine is the synthetic version, chemically identical to it. Doctors and Australian product leaflets use both names for the same medicine.

What happens if I miss a dose of levothyroxine?

The Australian leaflet says to take it as soon as you remember, unless it is almost time for your next dose, in which case skip the missed one. Don't take a double dose to make up for it. If you are unsure, ask your pharmacist.

Do I need a prescription for levothyroxine in Australia?

Yes. Levothyroxine is prescription only, so every pharmacy needs a script from your doctor. On the PBS, a box of 200 tablets costs no more than $25, or $7.70 with a concession card, plus a small brand charge for some brands.

What if I become pregnant while taking levothyroxine?

Tell your doctor as soon as you are pregnant or planning to be. The Australian leaflet says levels need to be watched carefully in pregnancy and the dose may need to be increased. Don't stop or change it yourself.

The honest takeaway

Levothyroxine is simply your own thyroid hormone in tablet form, and for most people it is a long-term, low-fuss medicine. The details that matter are practical: take it the same way every day on an empty stomach, keep food 30 to 60 minutes away and mineral supplements several hours away, know your brand, store it the way your leaflet says, and have your levels checked about six weeks after any change. If something doesn't feel right, raise it with your doctor rather than changing anything yourself.

ThyroBase is a nutritional supplement and is not intended to diagnose, treat, cure, or prevent any disease. It is designed to sit alongside your thyroid medication, not replace it. This article is general information, not medical advice. Never start, stop or change a supplement or prescription medication without speaking to your doctor or pharmacist first.

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