Do You Really Need to Take a Probiotic?
If you've ever wandered down the supplement aisle, you will have seen that probiotics are everywhere. They're marketed for gut health, bloating, IBS, digestion, immunity and more. Some contain billions of bacteria and make impressive-sounding claims about “rebalancing” or “restoring” your gut microbiome.
What exactly is the gut microbiome you ask?
You gut microbiome is the collection of microscopic organisms that live in your gut and help your body function. Think of your gut as a garden - the microbes are the plants and other organisms living in your garden - the more variety of plants, the better. Our gut microbiome contains trillions of microbes that can:
Help break down food that your body can't digest on it's own
Help protect you from harmful germs
Produce useful substances, including some vitamins and other chemicals
Communicate with your immune system and influence other aspects of your health
It's understandable if you've wondered....do I actually need to take a probiotic? The short answer is: probably not…at least not simply because you want a "healthier gut".
That doesn't mean there's no place for probiotics. There are situations where a particular probiotic may be helpful. But whether a probiotic is worth taking depends on what you're hoping to achieve, which probiotic you're considering and what the evidence says about that particular use.
What is a probiotic?
A probiotic is a live microorganism that provides a health benefit when consumed in an adequate amount. You may recognise names such as Lactobacillus or Bifidobacterium on probiotic labels. But these names alone don't tell us whether a product will work for you. Different probiotic strains can have different effects. Evidence that one strain helps with a particular symptom doesn't automatically apply to another product containing the same species. Unfortunately, selecting a probiotic isn't as simple as choosing the product with the biggest number of bacteria. More bacteria do not necessarily mean more benefit. What matters is whether the specific strain, dose and combination have been studied for the health outcome you're interested in.
Do you need a probiotic for a healthy gut?
If you're generally well and don't have a particular gastrointestinal condition or symptom you're trying to manage, there isn't strong evidence that you need a probiotic supplement to maintain a healthy gut. Your gut is already home to a complex community of microorganisms. Taking a probiotic doesn't simply replace your existing bacteria with “good” bacteria, nor does it necessarily permanently change your microbiome.
A 2026 systematic review and meta-analysis of randomised controlled trials in healthy people found no significant improvement in several commonly measured measures of gut microbiome diversity following probiotic supplementation. Importantly, this doesn't mean probiotics can never have an effect. It means we shouldn't assume that taking one automatically makes your microbiome more diverse, more balanced or “healthier.”
We also don't currently have one simple definition of what the “perfect” gut microbiome looks like. Your microbiome is influenced by your diet, medications, age, environment and individual biology (and researchers are still working out which microbial changes actually matter for health). So, if you're taking a probiotic simply because you feel like you should, there's no good evidence that everyone benefits from doing so.
What if I have IBS?
This is where things get more interesting. Probiotics have been extensively studied in people with IBS, and some studies have found improvements in overall symptoms, abdominal pain or bloating. However, the results aren't consistent across all probiotic products. A 2023 systematic review and meta-analysis included 82 randomised controlled trials involving more than 10,000 people with IBS. Some probiotic interventions improved overall IBS symptoms and individual symptoms such as abdominal pain and bloating, but results varied substantially between strains and outcomes.
A 2026 umbrella review found a similar pattern: probiotics may provide modest improvements in some IBS symptoms, but the certainty of evidence was predominantly low or very low.
A particular probiotic may be worth trialling for some people, but it shouldn't replace an individualised approach to IBS management. As dietitians, we also need to consider the bigger picture…your usual eating pattern, fibre intake, bowel habits, meal patterns, symptom triggers and nutritional adequacy. There simply isn't one diet (or one supplement) that works for everyone with IBS.
What about bloating?
Bloating is one of the most common reasons people try a probiotic. What's important to remember here is that bloating is a symptom, not a diagnosis. It can occur alongside IBS and constipation, but there are many possible contributors. For some people, symptoms may relate to particular fermentable carbohydrates. For others, constipation, meal patterns or gut sensitivity may be more relevant. So simply adding a probiotic may not address why you're bloated in the first place. If you're regularly bloated, it can be more useful to ask “why?” rather than immediately asking “which probiotic should I buy?” And if symptoms are persistent, worsening or significantly affecting your quality of life, getting an appropriate assessment is more useful than trying supplement after supplement.
What about probiotics after antibiotics?
This is one situation where there is evidence that some probiotics can help. A 2021 systematic review and meta-analysis of 42 trials involving more than 11,000 adults found that probiotics taken alongside antibiotics reduced the relative risk of antibiotic-associated diarrhoea by approximately 37%. However, the effect varied depending on factors including the probiotic strain and dose. This doesn't mean that everyone taking antibiotics needs a probiotic, or that any probiotic will prevent diarrhoea. Rather, particular probiotic interventions may be useful in particular circumstances. If you've been prescribed antibiotics and are considering a probiotic, your doctor or pharmacist can help you decide whether it's appropriate for you.
If I want to try a probiotic, how should I choose one?
If you've decided with your healthcare professional that a probiotic is worth trying, don't let the marketing do the choosing for you!
Look for the specific strain. Ideally, the product should identify the microorganism down to the strain level, so you can compare
it with the evidence for the condition or symptom you're trying to manage.
1. Have a clear goal.
Instead of: “I'm taking this for gut health.”
Try: “I'm going to trial this to see whether it improves my IBS-related bloating.”
That's much more useful because you have something specific to monitor.
2. Give it a defined trial period.
For IBS, The National Institute for Health and Care Excellence (NICE) recommends taking the probiotic at the manufacturer's recommended dose for at least four weeks while monitoring your symptoms. And to be honest, in clinic, we often give a probiotic a crack for a good 12 weeks before making the call on whether or not we feel it's making any meaningful impact.
You don't need to keep taking a supplement indefinitely simply because the label says it's “supporting your gut”. What about yoghurt, kefir and fermented foods? You may have heard that foods such as yoghurt, kefir, kimchi and sauerkraut are “natural probiotics”. There's an important distinction here: some fermented foods contain live microorganisms, but not every fermented food is technically a probiotic. For a microorganism to meet the scientific definition of a probiotic, it needs to have demonstrated a health benefit when consumed in an adequate amount. So, think of fermented foods as nutritious foods that may also provide live microorganisms, rather than automatically as alternatives to probiotic supplements. Yoghurt with live cultures and kefir are examples of foods that can contain live microorganisms. Traditionally, fermented vegetables such as kimchi and sauerkraut can contain them too, although the types and amounts can vary between products.
What we really should be focusing on?
This is where nutrition really matters. A varied diet containing a range of plant foods (including vegetables, fruit, wholegrains, legumes, nuts and seeds) provides different types of fibre and other compounds that interact with your gut microbiome.
You don't need to follow a complicated “gut health diet”.
Variety is more important than perfection.
And if you have IBS, “eating more fibre” isn't necessarily the right advice for everyone...in fact, sometimes it can worsen symptoms! The type, amount and timing of fibre can all affect symptoms. It's about finding an eating pattern that supports your nutritional needs while also being comfortable, sustainable and realistic for you.
A dietitian can help you look at the bigger picture and work out whether a probiotic is appropriate…or whether another approach is likely to be more useful. Sometimes the best gut-health strategy isn't adding another supplement. It's getting the right nutrition advice for you.
The information in this article is intended for general education purposes only and is not a substitute for personalised medical or dietary advice. Always consult with your doctor, dietitian, or qualified health professional before making any changes to your health or nutrition plan.
