Best Prebiotic Supplements in Australia (2026)

Probiotics get most of the attention, but prebiotics — the fibres that feed the beneficial bacteria already living in your gut — are arguably just as important, and often overlooked entirely.

What Are Prebiotics, Exactly?

Prebiotics are types of fibre that your body can't digest, but that beneficial gut bacteria can ferment and use as fuel. Common prebiotic fibres include inulin, fructooligosaccharides (FOS), galactooligosaccharides (GOS), and resistant starch. As your gut bacteria ferment these fibres, they produce short-chain fatty acids that support gut lining health and reduce inflammation.

Prebiotics vs Probiotics: Working Together

Taking a probiotic without adequate prebiotic intake is a bit like introducing new bacteria into your gut without giving them anything to eat — they're less likely to thrive and establish themselves. This is why combination "synbiotic" products, which contain both, have become increasingly popular, and why pairing a probiotic supplement with prebiotic-rich foods or a standalone prebiotic tends to produce better results than either alone.

What to Look for in a Prebiotic Supplement

• Fibre type: Inulin and FOS are the most researched and widely available prebiotic fibres in supplement form.
• Dose: Effective doses in research typically range from 5-10g per day — check the label rather than assuming more is automatically better, since higher doses are more likely to cause bloating, especially when starting out.
• Minimal additives: Look for products without excessive added sugars or artificial sweeteners, which can undermine the gut benefits you're trying to achieve.

Resistant Starch: An Overlooked Prebiotic

Resistant starch, found in cooled cooked potatoes and rice, green bananas, and legumes, is a lesser-known but well-studied prebiotic fibre. Cooling starchy foods after cooking (even reheating them afterward) changes their starch structure, making more of it resistant to digestion and available to feed gut bacteria — a simple, low-cost way to boost prebiotic intake from foods you likely already eat.

Are Synbiotics Worth It?

Synbiotic products, which combine prebiotics and probiotics in one formula, are convenient and can work well, but it's worth checking that both components are present in meaningful, clearly labelled amounts rather than one being included in a token quantity mainly for marketing purposes. A well-formulated synbiotic can simplify your routine without sacrificing effectiveness compared to taking two separate products.

Our Pick

Swisse Ultiboost Gut Health combines a prebiotic and probiotic formula with soothing ingredients like slippery elm and aloe vera, making it a solid all-in-one option if you'd rather not manage separate prebiotic and probiotic products.

Food Sources vs Supplements

Garlic, onion, leeks, asparagus, and slightly under-ripe bananas are all naturally rich in prebiotic fibres. A supplement is useful for convenience and a guaranteed, consistent dose, but building prebiotic-rich foods into your regular diet is a reasonable complementary strategy rather than an either-or choice.

Potential Side Effects

Bloating and gas are common when starting a prebiotic supplement, particularly at higher doses, since you're essentially feeding a fermentation process in your gut. Starting with a lower dose and increasing gradually over 1-2 weeks significantly reduces this adjustment period for most people.

Building Tolerance Gradually

Nearly everyone who starts a prebiotic supplement experiences some initial adjustment period. Rather than avoiding prebiotics because of this, most people find that starting at roughly a quarter of the labelled dose for the first week, then gradually increasing every few days, avoids most of the discomfort while still building toward the full effective dose over 2-3 weeks.

The Bottom Line

A quality prebiotic supplement is a reasonable, often-overlooked complement to a probiotic routine, particularly if your diet is naturally low in prebiotic-rich foods like garlic, onion, and legumes. Start low, increase gradually, and consider a combination formula if you'd prefer a single, simpler product.