How we chose these products
We evaluated fibre supplements available on Amazon UK based on four criteria:
Evidence. Does peer-reviewed research support the fibre type for the claimed benefit? We prioritised fibres backed by systematic reviews and meta-analyses, not single small studies.
Dosing transparency. Does the product clearly state the fibre content per serving, and does that serving align with the doses used in clinical research?
Ingredient purity. We favoured products with minimal additives. A fibre supplement should contain fibre, not sweeteners, fillers, or proprietary blends that obscure the actual dose.
Value. We calculated cost per effective daily dose, not cost per gram. A cheap powder that requires 20g to hit the research threshold is not cheaper than a premium powder that works at 12g.
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What are the six fibre types worth knowing?
Before the product list, a quick orientation. Most fibre supplements sold in the UK fall into one of six categories. Each works differently. For a deeper look at how the European fibre gap affects supplement choices, start there.
Chicory inulin is a soluble prebiotic fibre fermented by gut bacteria to produce short-chain fatty acids, particularly butyrate. It is the only fibre with a proprietary EFSA Article 13.5 health claim: at 12g/day, chicory inulin from BENEO’s Orafti source “contributes to maintenance of normal defecation by increasing stool frequency” (EFSA, 2015).1 Note: chicory inulin is high-FODMAP and may cause bloating at higher doses, particularly if introduced too quickly. Start at 4g/day and ramp up over 2 weeks.
Psyllium husk (ispaghula) is a gel-forming soluble fibre that absorbs water and adds bulk to stool. It is the most widely recommended fibre for constipation by UK healthcare professionals and the active ingredient in Fybogel, an NHS-listed OTC product. Psyllium also has strong evidence for lowering LDL cholesterol (Wei et al., 2009, meta-analysis).2 Well tolerated when taken with adequate water (at least 250ml per serving). For a detailed comparison of these two fibres, see our chicory inulin vs. psyllium husk guide.
PHGG (partially hydrolysed guar gum) is a low-viscosity soluble fibre derived from guar beans. It dissolves completely in liquid, is tasteless, and produces minimal gas compared to other prebiotic fibres. Clinical evidence supports its use for IBS-related symptoms, both constipation-predominant and diarrhoea-predominant (Giannini et al., 2006).3 The gentlest option for people with sensitive digestion or those on GLP-1 medications with existing nausea.
Acacia fibre (gum arabic) is a slowly fermented soluble fibre that supports microbiome diversity without the rapid gas production of faster-fermenting fibres like inulin. Limited but promising research on its prebiotic effects (Calame et al., 2008). Good for people who experience bloating with inulin.
Wheat dextrin is a soluble fibre often sold as “Benefiber” in other markets. Lower clinical evidence base than psyllium or inulin. Functions as a bulk former. Gluten-free despite the wheat origin (the gluten is removed during processing), but may concern people with coeliac disease.
Blends combine two or more fibre types, typically inulin + acacia + FOS, or psyllium + inulin. These can offer broader microbiome support but make it harder to identify which fibre is responsible for any side effects. Best for people who already know their tolerance.
What are the 9 best fibre supplements available in the UK?
1. NKD Living Inulin High Grade Prebiotic Fibre Powder (1kg)
Fibre type: Chicory inulin Fibre per serving: 8.9g per 10g serving (89% fibre content) Price: ~£13 for 1kg (~100 servings) Cost per day at 12g dose: ~£0.16
The best-value chicory inulin on Amazon UK. Manufactured in Belgium (the European hub for chicory inulin production), packed in the UK. 89% pure fibre content is high for a consumer product. Mild sweet taste. Dissolves easily in hot drinks and smoothies. Over 1,400 reviews averaging 4.5 stars.
At the 12g/day dose needed for the EFSA health claim, one bag lasts about 83 days. That is roughly 16p per day for a clinically relevant prebiotic dose.
The trade-off: chicory inulin at 12g/day will cause gas and bloating if you jump straight to full dose. Start at 4g (half a tablespoon) for the first week.
2. Natures Aid Inulin Powder (250g)
Fibre type: Chicory root inulin with FOS Fibre per serving: ~9g per 10g serving Price: ~£8 for 250g (~25 servings) Cost per day at 12g dose: ~£0.38
A smaller-format option for people who want to test chicory inulin before committing to a kilo bag. Includes naturally occurring fructo-oligosaccharides (FOS) alongside the inulin, which adds shorter-chain prebiotic fibres. Vegan, non-GMO, gluten-free. 100% pure with no additives.
Higher per-gram cost than NKD Living, but the 250g format reduces the risk of wasting product if you discover inulin does not agree with your digestion.
3. Premium Inulin Powder (1kg) by The Pantry
Fibre type: Chicory root inulin Fibre per serving: ~9g per 10g serving Price: ~£13 for 1kg Cost per day at 12g dose: ~£0.16
Sourced from Belgium, packed in the UK. Comparable to NKD Living in purity and price. 100% recyclable packaging. Vegan, non-GMO, palm oil free. A solid alternative if NKD Living is out of stock.
4. KIKI Health Organic Psyllium Husk Powder (275g)
Fibre type: Psyllium husk (ispaghula) Fibre per serving: ~5g per 7g serving Price: ~£12 for 275g (~39 servings) Cost per day at 7g dose: ~£0.31
The highest-quality psyllium husk powder we found on Amazon UK. Organic, finely milled for easier mixing. KIKI Health is a UK-based brand with a reputation for clean formulations. Psyllium is the first-line recommendation for constipation from most UK pharmacists and dietitians.
Take with at least 250ml of water per serving. This is non-negotiable with psyllium: without adequate fluid, it can worsen constipation or cause intestinal blockage.
5. NKD Living Psyllium Husk Powder (500g)
Fibre type: Psyllium husk Fibre per serving: ~4g per 5g serving Price: ~£10 for 500g (~100 servings) Cost per day at 10g dose: ~£0.20
A better-value psyllium option than KIKI Health, though not organic. Tested for heavy metals, micro-organisms, and pesticides (stated on product page). 500g bag offers roughly 50 days at a 10g daily dose. Fine powder texture mixes reasonably well, though psyllium will always thicken liquid. Best mixed into a smoothie rather than plain water.
6. Fybogel Orange Sachets (30 pack)
Fibre type: Ispaghula husk (psyllium) Fibre per serving: 3.5g per sachet Price: ~£7 for 30 sachets Cost per day at 1-2 sachets: ~£0.23-0.47
The pharmacy standard. Fybogel is the most widely recognised fibre supplement in the UK, stocked by Boots, Superdrug, and every high-street pharmacy. Listed in the British National Formulary. Contains orange flavouring and sweetener (aspartame in some variants, so check the label if relevant).
The convenience trade-off: pre-portioned sachets are easy but more expensive per gram than bulk powder. Best for people who want a familiar, pharmacy-backed product and prefer not to measure their own dose.
7. OptiFibre (PHGG) Powder (250g)
Fibre type: Partially hydrolysed guar gum Fibre per serving: 5g per serving Price: ~£15 for 250g (~50 servings) Cost per day at 5-10g dose: ~£0.30-0.60
The best option in the UK for people with sensitive digestion, IBS, or GLP-1 medication users who experience nausea with other fibres. OptiFibre is made by Nestle Health Science and uses PHGG as its sole ingredient. Dissolves completely clear. No taste, no texture change in drinks or food. Low-FODMAP certified.
Clinical research on PHGG consistently shows improvements in stool frequency and consistency with significantly less gas production than inulin or psyllium (Takahashi et al., 2004). If you have tried other fibres and experienced bloating, PHGG is worth trying. For more on how GLP-1 medications create a fibre problem, see our detailed guide.
Higher cost per gram than psyllium or inulin, but for GLP-1 users managing nausea alongside constipation, the tolerability premium is justified.
8. Healthy Origins Healthy Fiber PHGG (225g)
Fibre type: Partially hydrolysed guar gum Fibre per serving: 6g per scoop Price: ~£18 for 225g (~30 servings) Cost per day at 6g dose: ~£0.60
An alternative PHGG option from a US brand with strong supplement credentials. Single ingredient. Dissolves clear. Slightly higher price point than OptiFibre for a smaller pack. Available on Amazon UK with Prime delivery.
Choose this over OptiFibre if you prefer a brand with a longer track record in the clinical supplement space, or if OptiFibre is out of stock.
9. Well Within 3-in-1 Soluble Fibre Powder (200g)
Fibre type: Inulin + acacia + FOS blend Fibre per serving: 6g per scoop (12g per 2-scoop serving) Price: ~£15 for 200g Cost per day at 12g dose: ~£0.90
A UK brand combining three complementary soluble fibres: chicory inulin for prebiotic support, acacia for slower fermentation and gentler tolerance, and FOS for short-chain prebiotic diversity. The blend approach means each fibre is present at a lower individual dose, which can reduce the gas production associated with high-dose inulin alone.
40% of the NHS daily fibre intake in two scoops. The trade-off: it is more expensive per day than single-ingredient powders, and if you experience side effects, you cannot isolate which fibre is the cause.
How do these products compare?
| Product | Fibre type | Daily dose | Cost/day | Best for |
|---|---|---|---|---|
| NKD Living Inulin 1kg | Chicory inulin | 12g | £0.16 | Prebiotic support (best value) |
| Natures Aid Inulin 250g | Chicory inulin + FOS | 12g | £0.38 | Testing inulin tolerance |
| Premium Inulin 1kg | Chicory inulin | 12g | £0.16 | Alternative to NKD Living |
| KIKI Health Psyllium 275g | Psyllium husk | 7-14g | £0.31 | Constipation relief (organic) |
| NKD Living Psyllium 500g | Psyllium husk | 10g | £0.20 | Constipation relief (value) |
| Fybogel Orange 30s | Ispaghula husk | 3.5-7g | £0.23-0.47 | Pharmacy convenience |
| OptiFibre PHGG 250g | PHGG | 5-10g | £0.30-0.60 | Sensitive digestion / IBS |
| Healthy Origins PHGG 225g | PHGG | 6g | £0.60 | PHGG alternative |
| Well Within 3-in-1 200g | Inulin + acacia + FOS | 12g | £0.90 | Broad prebiotic blend |
Which fibre type is right for you?
If your primary goal is constipation relief: Start with psyllium husk. It has the strongest evidence base for improving stool frequency and consistency. Take with 250ml+ of water.
If your primary goal is gut microbiome support: Chicory inulin at 12g/day has the strongest prebiotic evidence and the only proprietary EU health claim for bowel function. Ramp up slowly.
If you are on a GLP-1 medication (semaglutide, tirzepatide): Consider starting with PHGG or acacia fibre. GLP-1 medications slow gastric emptying, and faster-fermenting fibres like inulin can worsen nausea and bloating in the early weeks. Once your GI symptoms stabilise, you can gradually introduce inulin for its prebiotic benefits. If you are switching to the oral formulation, read our guide on how oral Wegovy’s fasting rule changes fibre timing.
If you have IBS or FODMAP sensitivity: PHGG is the safest starting point. It is low-FODMAP certified and produces less gas than other soluble fibres.
If you want both regularity and prebiotic support: A blend like Well Within 3-in-1, or combining psyllium (morning) with a lower dose of inulin (evening), gives you complementary mechanisms.
How should you start taking fibre supplements?
- Pick one fibre type. Do not combine multiple new fibres at once.
- Start at half the recommended dose (or less) for the first 5 to 7 days.
- Drink at least 250ml of water with every serving.
- Increase by 2 to 4g every few days until you reach your target dose.
- If bloating or gas become uncomfortable, hold at the current dose for another week before increasing.
- Take fibre supplements at least 1 hour before or 2 hours after medications to avoid absorption interference.
Which fibre should you choose?
If your main concern is constipation relief, look for psyllium husk powder. It is the most clinically studied fibre for improving stool frequency and consistency. Take it with at least 250ml of water per serving. Browse psyllium husk powder on Amazon
If you are starting a GLP-1 medication (Ozempic, Wegovy, Mounjaro, Zepbound), look for PHGG (partially hydrolysed guar gum) or Sunfiber. PHGG is the gentlest fibre for GLP-1 users because it produces minimal gas, dissolves completely, and is low-FODMAP certified. Avoid jumping straight to high-dose inulin in the first weeks. Browse PHGG / Sunfiber on Amazon
If you want prebiotic and microbiome support, look for chicory inulin powder. At 12g/day it carries the only proprietary EU health claim for bowel function. Start at 4g/day and ramp up over 2 weeks to avoid gas and bloating. Browse chicory inulin powder on Amazon
If you have IBS or FODMAP sensitivity, start with PHGG or acacia fibre. Both are slow-fermenting, low-FODMAP, and produce significantly less gas than inulin or psyllium. Browse acacia fibre on Amazon
If you already know your tolerance and want broader microbiome coverage, look for a fibre blend that combines two or more soluble fibres. Trade-off: if side effects occur, you cannot isolate which fibre is responsible. Browse prebiotic fibre blends on Amazon
Frequently asked questions
Can I take fibre supplements with GLP-1 medications like Ozempic or Wegovy?
Yes, but timing matters. Fibre supplements should be taken at least 1 hour before or 2 hours after your medication. For oral semaglutide (Rybelsus), the 30-minute empty-stomach fasting period means fibre must be taken at a separate meal entirely. Read more: Oral Wegovy and fibre: how the fasting rule changes everything.
How much fibre should I take per day?
The NHS recommends 30g per day from all sources (food + supplements). Most UK adults consume around 18g from food. A supplement providing 10 to 12g per day can close most of the gap.
Do fibre supplements cause bloating?
Some types more than others. Inulin and FOS ferment faster and produce more gas. PHGG and acacia fibre ferment slowly and cause less bloating. Ramping up gradually is the single most effective way to reduce side effects with any fibre type.
Is chicory inulin safe?
Yes. Chicory inulin has been consumed as a food ingredient for centuries and has GRAS (Generally Recognised As Safe) status. The EFSA authorised a specific health claim for chicory inulin at 12g/day.1 People with IBS or FODMAP sensitivity should introduce it cautiously.
What is the difference between inulin and psyllium?
Different mechanisms. Psyllium absorbs water and adds bulk to stool (mechanical action). Inulin feeds beneficial gut bacteria that produce short-chain fatty acids (prebiotic action). Both support regularity, but through different pathways. We compared them in detail: chicory inulin vs. psyllium husk.
Are fibre gummies effective?
Most fibre gummies provide 2 to 4g of fibre per serving. The clinical research on chicory inulin requires 12g/day. You would need 3 to 6 gummies to approach a meaningful dose, and the added sugars and flavourings add unnecessary ingredients. Powder is more effective and more cost-efficient.
* Affiliate link. See our disclosure for details.
This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting, stopping, or changing any medication or supplement regimen.
Last reviewed: April 7, 2026. Prices and availability are approximate and may change.
Footnotes
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EFSA Panel on Dietetic Products, Nutrition and Allergies (2015). Scientific Opinion on the substantiation of a health claim related to “native chicory inulin” and maintenance of normal defecation by increasing stool frequency. EFSA Journal, 13(1):3951. ↩ ↩2
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Wei ZH, Wang H, Chen XY, et al. (2009). Time- and dose-dependent effect of psyllium on serum lipids. European Journal of Clinical Nutrition, 63(7):821-827. ↩
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Giannini EG, Mansi C, Dulbecco P, Savarino V (2006). Role of partially hydrolyzed guar gum in the treatment of irritable bowel syndrome. Nutrition, 22(3):334-342. ↩