How Much Does A Hydrogen Breath Test Cost?

June 4, 2025

In the UK, a hydrogen breath test costs anything between nothing at all (on the NHS) to around £500 at a private clinic. Most options are somewhere in the middle.

If you’ve got IBS symptoms, and you’ve been trying to find out why, the chances are you’ve come across SIBO (small intestinal bacterial overgrowth) as a possible root cause.

SIBO is tricky to test for, but the best option we have right now is something called a hydrogen breath test. It’s known as the ‘gold standard’ SIBO test because experts all around the world agree that it’s the most accurate and reliable method.

But what is a hydrogen breath test, and why does the price vary so much? Read on to find out.

Cost of hydrogen breath test

If your GP agrees to test you for SIBO, you’ll be referred to a gastroenterologist at a hospital who will carry out the test. Because this will happen through the NHS, it’s free.

However, some doctors don’t accept that SIBO is a real condition. If your GP is one of them, it will be difficult to get a referral. On the other hand, many doctors today do recognise SIBO and more and more hospitals are offering the test.

If you’re having trouble getting the test through your GP, don’t worry. It happens a lot, and private testing is relatively inexpensive (compared to other kinds of private tests, like colonoscopies, for example). If you’d like to get a private test, you have two options:

Look for a private clinic that carries out SIBO testing and attend in person
Get a SIBO test sent to your address and complete it at home

Attending a clinic

If you choose to attend a clinic, it’s usually more expensive than an at-home test because you’re essentially paying for their overhead costs: the building and the staff, for example. But, you might feel more comfortable with a nurse or doctor on hand to make sure you’re doing the test properly.

One drawback is that you’ll have to take three hours out of your day to do the test, and factor in time travelling to and from the clinic too. Another drawback is the cost: clinics usually charge more than at-home testing providers.

Every clinic sets its own price, but they usually start at around £250, which doesn’t include any interpretation other than telling you whether you have a positive or negative result.

What is a hydrogen breath test?

Hydrogen breath tests are used to diagnose SIBO.

However, they’re also used to diagnose other conditions, like fructose or lactose intolerance. Confusingly, fructose or lactose intolerance can also be caused by SIBO.

It’s very important that your SIBO test analyses both hydrogen and methane levels, because both gases are involved in SIBO. If your test only looks for hydrogen, you could easily get a false negative.

To take a hydrogen breath test, you’ll need to drink a sugary solution called lactulose, after eating a special diet then fasting the day before. You’ll then breathe into bags supplied with the test kit every 20 minutes for three hours afterwards.

When you’re finished, you’ll send the bags off to a lab where technicians will analyse the levels of hydrogen (and hopefully methane) in your breath, which reflects the levels of bacteria in your small intestine.

Hydrogen breath test cost UK

The cost of a hydrogen breath test in the UK can be anything from nothing up to about £500.

They’re free on the NHS, and around £250 at a private clinic. If you want to attend a clinic in London, for example, the cost is likely to be more. At-home tests are usually cheaper.

Cost of private hydrogen breath test UK

If you want to attend a clinic for your hydrogen breath test, prices start at around £250, but this doesn’t include any advice or treatment protocol.

There are many clinics that offer hydrogen breath testing around the UK today, as SIBO becomes a more recognised condition. Each one sets its own price so it’s worth doing some research to find the best one in your area.

At-home tests are cheaper, and you’ll get exactly the same equipment in your test kit as the clinics use for their patients.

Accuracy of results

Leading practitioners use the hydrogen/methane breath test for SIBO because overall, it gives the most accurate and reliable results.

However, no test is perfect, and false negatives and false positives do happen. That means you could have SIBO, yet your test result is negative. Or, you could get a positive result when you don’t have SIBO. While this is unlikely to happen to you, it’s not impossible.

What do my results mean?

Your results will fall into one of four categories:

Negative for SIBO

If you test negative, it’s possible that you have dysbiosis lower down in your large intestine (also known as your colon), or a fungal overgrowth, which doesn’t show up on SIBO breath tests.

Positive for hydrogen overgrowth

Hydrogen is more likely to result in diarrhoea. Hydrogen SIBO has been shown to respond well to protocols using herbs like oregano or berberine. [1]

Positive for methane overgrowth

Methane is more likely to result in constipation. There’s evidence that allicin in garlic reduces the archaea that produce methane. This study was on sheep [2] but it’s part of a standard protocol used by naturopathic doctors and practitioners for methane SIBO.

Positive for hydrogen and methane overgrowth

It’s possible to have both hydrogen and methane overgrowth. An experienced practitioner can create a protocol to reduce the microbes responsible for both these gases.