Clinical Probiotics UK: Evidence Guide — Symprove, Alflorex, Optibac, Bio-Kult & CDS22-formula Compared
Not all probiotics are equal — and in the UK market, the gap between a retail probiotic and a clinically evidenced one is significant. This guide explains what makes a probiotic "clinical grade," compares the five most-discussed options for UK consumers by strain identity and published trial data, and covers the signs probiotics are working.
Clinical probiotics are food supplements whose specific bacterial strains have been studied in published human randomised controlled trials — not a regulatory term, but a meaningful evidence distinction. In the UK, they are regulated by the Food Standards Agency (FSA) as food supplements, not medicines, and no prescription is required.
The De Simone Formulation — now sold in the UK as CDS22-formula (8 strains, 450 billion CFU per sachet, £19.50 for 12 sachets) — has the most extensive published evidence base of any probiotic available to UK consumers, referenced in over 200 scientific publications and named exclusively in the American Gastroenterological Association (AGA) 2024 pouchitis guideline (Barnes et al., PMID 38128971). Alflorex (B. infantis 35624) has strong evidence for IBS-D specifically.
CFU count is not a reliable indicator of efficacy — strain identity and evidence match to your situation matter more. Signs probiotics are working include reduced bloating and improved bowel regularity, typically appearing within 2–4 weeks. UK VAT on food supplements is 20%.
Clinical probiotic (definition): A probiotic supplement containing bacterial strains whose specific strain identities — confirmed by NCIMB, ATCC, or DSM codes — have been studied in at least one published human randomised controlled trial, distinguishing them from generic "multi-strain" products formulated without strain-specific evidence.
A clinical probiotic supplement in the UK is a food supplement containing bacterial strains with a published human trial evidence base — regulated by the FSA, not a medicine, and available without prescription. The term "clinical grade" is not a legal classification; it describes the depth of published evidence behind the specific strains in the product. The strongest human evidence for a UK-available probiotic formulation is held by the De Simone Formulation (CDS22-formula, £19.50, 450 billion CFU, cold-chain delivered by Probiotic.co.uk). No probiotic supplement is authorised under UK food supplement regulation to make disease treatment claims.
- What "clinical grade" means: Strains published in human RCTs — not a UK regulatory category
- FSA regulatory status: Food supplement — not a medicine, no prescription required
- UK VAT on supplements: 20%
- Most published evidence: De Simone Formulation (CDS22-formula) — 200+ publications, 80+ clinical studies
- AGA 2024 guideline (PMID 38128971): Evidence for pouchitis prevention "limited to the De Simone Formulation"
- Strongest IBS-D strain evidence: B. infantis 35624 (Alflorex) — Whorwell et al., 2006, PMID 16863564
- CFU is not a proxy for efficacy: Alflorex trials used 1×10⁸ CFU (1 billion) — lower doses outperformed higher in one arm
- Signs probiotics are working: Reduced bloating, more regular bowel movements — typically within 2–4 weeks
- CDS22-formula: 8 NCIMB-coded strains, 450B CFU per sachet, refrigerated, £19.50 / 12 sachets
- Not a regulatory term — the FSA does not classify supplements as "clinical grade"
- Not a medicine — no UK probiotic supplement has marketing authorisation as a medicinal product
- Not proven to treat, cure or prevent any disease — including IBS, UC, or pouchitis — as a food supplement claim
- Not determined by CFU count alone — higher CFU does not mean stronger evidence or better efficacy
- Not proven to benefit otherwise healthy people without digestive symptoms — evidence is population-specific
- Not interchangeable across products — evidence for one strain does not transfer to another product's strains
What is well-supported: Barnes et al. (AGA, Gastroenterology, 2024, PMID 38128971) identified the De Simone Formulation as the only probiotic with sufficient evidence for preventing pouchitis recurrence after colectomy; Gionchetti et al. (Gastroenterology, 2000, PMID 10930365) and Mimura et al. (Gut, 2004, PMID 14684584) showed the formulation maintained pouchitis remission at 1 year in RCTs. Whorwell et al. (Am J Gastroenterol, 2006, PMID 16863564) demonstrated B. infantis 35624 (Alflorex) significantly improved IBS global symptoms vs placebo.
What is not proven: No probiotic supplement is proven to treat, cure or prevent any gastrointestinal disease as a food supplement; evidence for probiotics in otherwise healthy UK adults without diagnosed conditions is limited; CFU superiority claims are not supported by head-to-head trial data.
Most relevant human dose range: De Simone Formulation: 450 billion CFU per day (1 sachet) in most published trials; B. infantis 35624: 1×10⁸ CFU per day in the pivotal Whorwell 2006 RCT.
Key safety note: Immunocompromised individuals should consult a GP before use; the NHS advises seeing a GP if digestive symptoms persist for more than 3 weeks.
| Feature | Specification | Evidence Level |
|---|---|---|
| De Simone Formulation (CDS22) | 8 strains, 450B CFU/sachet, NCIMB-coded | Strong — 80+ clinical studies |
| AGA guideline endorsement | Barnes et al. 2024 (PMID 38128971) — pouchitis only | Published guideline (AGA 2024) |
| B. infantis 35624 (Alflorex) | Single strain, ~1B CFU, IBS-D evidence | Strong — Whorwell 2006 RCT |
| Symprove | Liquid multi-strain, lower CFU | Limited — one published RCT |
| Optibac Everyday | Multi-strain capsule, accessible retail | Moderate — brand research, limited independent RCTs |
| Bio-Kult | 14-strain capsule, available in Boots and H&B | Moderate — some strain data, limited formulation RCTs |
| CFU as efficacy indicator | Not a reliable proxy | Not supported — dose-response not linear |
| UK regulatory status | FSA food supplement — not a medicine | Established — UK food supplement law |
| UK VAT on supplements | 20% | Confirmed — HMRC food supplement classification |
The clinical research discussed in this article describes the De Simone Formulation as a studied compound in specific populations (IBD, pouchitis, IBS). It should not be read as a claim that CDS22-formula treats any condition. CDS22-formula is a food supplement, not a medicine. No authorised UK health claim is made.
CDS22-formula — Original De Simone Formulation
The 8-strain, 450 billion CFU formulation. Cold-chain delivered across the UK.
Probiotic.co.uk — authorised UK retailer · Cold-chain delivery · Not a medicine · 20% VAT included
- What "clinical grade" actually means
- Why CFU count is not a measure of efficacy
- Comparing UK probiotic brands: evidence by evidence
- The De Simone Formulation — CDS22-formula
- Signs probiotics are working — what to expect and when
- The VSL#3 and Vivomixx lineage explained
- Clinical probiotics in the UK — FSA regulation and VAT
- Clinical evidence reviewed
- Frequently asked questions
What "clinical grade" actually means
The phrase "clinical grade" is used widely in UK supplement marketing but has no legal definition under FSA food supplement legislation. In practice, it describes one thing: whether the specific bacterial strains in a product have been studied in published human randomised controlled trials.
Strain identity is the key variable. A strain name is more than a species name — Lactobacillus acidophilus is a species; Lactobacillus acidophilus NCIMB 30442 is a specific strain whose identity can be matched to published literature. When a manufacturer lists strain codes (NCIMB, ATCC, or DSM designations), the product can in principle be cross-referenced against published trial data. When they do not, it cannot.
This distinction matters because evidence from one strain does not transfer to another. A trial showing that B. infantis 35624 improves IBS-D symptom scores tells you nothing about a different Bifidobacterium strain — even if the species name looks similar on a label.
Strain codes (NCIMB, ATCC, or DSM) — CFU at time of use, not manufacture — refrigerated or confirmed shelf-stable — published trial reference (not just "clinically studied"). If none of these appear, the evidence claim is unverifiable.
Why CFU count is not a measure of efficacy
Colony forming units (CFU) indicate how many live bacteria are present in a product, but the relationship between CFU count and clinical outcome is not linear — and in some cases is inverted.
The pivotal Alflorex trial by Whorwell et al. (American Journal of Gastroenterology, 2006, PMID 16863564) used 1×10⁸ CFU per day — 100 million, or 1 billion — and found significant improvement in IBS global symptom scores and abdominal pain versus placebo.1 The study tested three doses; the higher doses did not outperform the lowest dose tested.
The De Simone Formulation trials — using 450 billion CFU per day — were conducted in a different population with different clinical outcomes (IBD, pouchitis). The dose reflects what was used in the relevant trials, not a claim that higher CFU is inherently superior.2
- More CFU does not mean a more effective probiotic
- 50 billion CFU with published RCTs is more evidence-backed than 100 billion CFU without any
- CFU at manufacture is different from CFU at time of use — refrigeration and packaging matter
- "Billions" in marketing does not indicate clinical validation
Comparing UK probiotic brands: evidence by evidence
Five products dominate the clinical probiotic conversation for UK consumers: CDS22-formula (De Simone Formulation), Alflorex (Precision Biotics), Symprove, Optibac, and Bio-Kult. Each has a different evidence profile, different strains, and different clinical populations in its published research.
| Product | Strains / CFU | Published RCTs | Primary evidence population | Format | Where to buy |
|---|---|---|---|---|---|
| CDS22-formula (De Simone Formulation) | 8 NCIMB strains · 450B CFU/sachet | 80+ clinical studies; AGA 2024 guideline | IBD, UC, pouchitis, IBS | Sachet (refrigerated) | Probiotic.co.uk — £19.50 / 12 sachets |
| Alflorex (Precision Biotics) | B. infantis 35624 · ~1B CFU | Strong — Whorwell 2006 RCT (PMID 16863564); additional IBS trials | IBS-D specifically | Capsule (shelf-stable) | Boots, Holland & Barrett, online |
| Symprove | Multi-strain liquid · lower CFU | One published RCT (Sisson et al., BMJ Open Gastro, 2014) — IBS | IBS (limited) | Liquid (refrigerated) | Symprove.com, Boots |
| Optibac Everyday | Multi-strain · variable CFU | Brand-funded research; limited independent RCTs for the formulation | General gut health | Capsule (shelf-stable) | Holland & Barrett, Boots, Tesco |
| Bio-Kult | 14 strains · varied CFU | Some published strain data; limited formulation-specific RCTs | General gut health | Capsule (shelf-stable) | Holland & Barrett, Morrisons, online |
The comparison table reflects published evidence as of June 2026. It is a factual summary — not a claim that any product treats any condition. Each product's evidence applies to the population studied in the cited trials, which may not match your situation.
Key takeaway: While mainstream brands serve daily general wellness, the De Simone Formulation (CDS22-formula) carries the deepest peer-reviewed evidence base of any probiotic formulation available to UK consumers — 200+ scientific publications, 80+ clinical studies, and the only formulation named by name in the AGA 2024 clinical practice guideline.
Live bacteria are proposed to compete with pathogenic organisms for gut mucosal binding sites, reducing colonisation by unwanted bacteria.
Evidence: Established in vitro; variable human RCT dataCertain strains are proposed to support tight junction integrity in the intestinal epithelium, a mechanism studied in IBD contexts for the De Simone Formulation.
Evidence: Preclinical and early human data; not proven in healthy adultsBacterial strains interact with toll-like receptors and dendritic cells in gut-associated lymphoid tissue, proposed to influence local immune responses.
Evidence: Animal models and mechanistic studies; limited human RCT proofMulti-strain formulations are studied for their ability to alter the relative abundance of gut microbial populations, as measured by microbiome sequencing in clinical trials.
Evidence: Mixed human RCTs; effect size and durability vary by formulationPublished RCTs measure patient-reported symptom scores (bloating, stool form, pain) as primary endpoints — the most directly applicable evidence for consumer decision-making.
Evidence: Strong for De Simone Formulation in IBD/pouchitis; strong for B. infantis 35624 in IBS-DBifidobacteria and lactobacilli ferment dietary fibre to produce short-chain fatty acids (SCFAs) including butyrate, proposed to support colonocyte energy metabolism.
Evidence: Established biochemically; clinical relevance in healthy adults unprovenThe De Simone Formulation — CDS22-formula in the UK
The De Simone Formulation — available in the UK as CDS22-formula — is an 8-strain probiotic mixture developed by Professor Claudio De Simone of the University of L'Aquila, Italy. It is the most studied probiotic formulation by name in the peer-reviewed literature and the only formulation referenced by name in the 2024 American Gastroenterological Association (AGA) clinical practice guideline on probiotics.3
Barnes et al. (Gastroenterology, 2024;166(1):59-85, PMID 38128971) state explicitly that evidence supporting probiotics for preventing pouchitis recurrence is "limited to the De Simone Formulation." The guideline is an AGA guideline — not the ACG (American College of Gastroenterology). This distinction matters because older product pages and some third-party sources incorrectly attribute the guideline to the ACG.
In the UK, the formulation is supplied as CDS22-formula — 8 strains identified by NCIMB codes, 450 billion CFU per 4.4g sachet. It is refrigerated (+2–8°C), cold-chain delivered by Probiotic.co.uk, and shelf-stable at room temperature for up to 7 days per the manufacturer's storage leaflet.
| Strain | NCIMB Code | Per sachet |
|---|---|---|
| Streptococcus thermophilus | NCIMB 30438 | 226 billion CFU |
| Bifidobacterium breve | NCIMB 30441 | 24 billion CFU |
| Bifidobacterium animalis subsp. lactis | NCIMB 30435 | 24 billion CFU |
| Bifidobacterium animalis subsp. lactis | NCIMB 30436 | 24 billion CFU |
| Lactobacillus acidophilus | NCIMB 30442 | 38 billion CFU |
| Lactobacillus plantarum | NCIMB 30437 | 38 billion CFU |
| Lactobacillus paracasei | NCIMB 30439 | 38 billion CFU |
| Lactobacillus helveticus | NCIMB 30440 | 38 billion CFU |
Older clinical literature and the US Visbiome product list these strains under DSM codes (DSM 24731–24737). The organisms are the same; the current UK CDS22-formula label uses NCIMB designations. When cross-referencing published trials, both code systems map to the same strains.
Signs probiotics are working — what to expect and when
"Signs probiotics are working" is one of the highest-volume low-KD queries in this space (2,400 monthly UK searches, KD 16). The answer is grounded in trial durations from published research — not testimonials.
The timeline below is based on endpoint measurement points used in published RCTs for the De Simone Formulation and B. infantis 35624. Individual responses vary, and these signals do not constitute a guarantee of effect.
The NHS advises consulting a GP for persistent digestive symptoms lasting more than 3 weeks, blood in stool, unexplained weight loss, or any symptoms that worsen rather than improve. Probiotics are food supplements — they are not a substitute for medical assessment of persistent or worsening symptoms.
The VSL#3 and Vivomixx lineage — what UK buyers need to know
If you previously purchased VSL#3 or Vivomixx in the UK and are looking to continue the same formulation, the brand history is essential context.
The De Simone Formulation was sold under the VSL#3 brand (Actial Srl) until 2016. After a commercial dispute between Professor De Simone and Actial Srl, the formulation left the VSL#3 brand. Per the European Crohn's and Colitis Organisation (ECCO) official statement of October 2023, the product currently sold as VSL#3 no longer contains the De Simone Formulation.
From 2016, the formulation was sold as Vivomixx (Mendes SA) until 2025. It is now supplied as CDS22-formula. The formulation — the 8-strain combination at 450 billion CFU — has remained constant throughout these name changes. Most pre-2016 "VSL#3" clinical studies relate to the formulation now supplied as CDS22-formula.
| Period | Brand name | Contains De Simone Formulation? | Notes |
|---|---|---|---|
| Until 2016 | VSL#3 (Actial Srl) | Yes | Most pre-2016 trial literature relates to this formulation |
| After 2016 | VSL#3 (current) | No | Per ECCO Oct 2023 official statement |
| 2016–2025 | Vivomixx (Mendes SA) | Yes | Same 8 strains; Halkjær 2020 (PMID 32617453) names Vivomixx |
| Now (UK) | CDS22-formula | Yes | 8 NCIMB-coded strains, 450B CFU, £19.50/12 sachets |
Check the label for the 8 NCIMB strain codes listed above. A product containing the De Simone Formulation will list all 8 strains with their NCIMB designations. If the label lists DSM codes, these map to the same strains in older literature — but NCIMB is the current labelling standard for the UK product.
Clinical probiotics in the UK — FSA regulation, VAT, and what the law says
All probiotic supplements sold in the UK — regardless of their evidence base or CFU count — are regulated as food supplements by the Food Standards Agency (FSA). They are not medicines. No UK probiotic supplement holds marketing authorisation as a medicinal product. No prescription is required to purchase any of the products discussed in this guide.
Health claims for probiotics are governed by retained EU Regulation 1924/2006 as it applies in Great Britain. No authorised health claims for probiotic bacteria have been approved under this framework. This means that any UK product claiming that a specific probiotic "treats," "cures," "prevents," or "relieves" a named disease or condition would be making a claim that is not compliant with UK food supplement law.
The MHRA (Medicines and Healthcare products Regulatory Authority) regulates any product making medicinal claims. Clinical research framing — as used in this guide — refers to the existence of published trials about the studied compound, not a medicinal function claim about the product.
Regulator: Food Standards Agency (FSA) · Medicines regulator: MHRA · Health claim law: Retained EC Regulation 1924/2006 · VAT on supplements: 20% (HMRC) · NHS reference: See a GP if digestive symptoms persist more than 3 weeks · Source: FSA food supplement guidance
Clinical evidence reviewed
The American Gastroenterological Association (AGA) published a clinical practice guideline on the role of probiotics in gastrointestinal disorders (Gastroenterology, 2024;166(1):59-85). The guideline evaluated the evidence for probiotics across multiple GI conditions and concluded that evidence favouring probiotics for preventing pouchitis recurrence after colectomy — the context most relevant to the search query "best probiotic for pouchitis UK" — is limited to the De Simone Formulation.
This is a published clinical guideline from a major gastroenterology professional body — not a product claim. The guideline covers IBD management contexts; it does not endorse any probiotic for use in otherwise healthy adults.
Barnes EL et al. Gastroenterology. 2024;166(1):59-85. PMID 38128971. DOI: 10.1053/j.gastro.2023.11.003
Randomised, double-blind, placebo-controlled trial in 40 patients with chronic relapsing pouchitis who had achieved remission with antibiotics. Patients received the De Simone Formulation (as VSL#3, 6g/day, equivalent to 450B CFU) or placebo daily for 9 months. Remission was maintained in 85% of the active group vs 6% in placebo (p<0.001).
This is the foundational pouchitis maintenance trial for the formulation. Limitations: small sample size (n=40), single centre, and the outcome was maintenance of antibiotic-induced remission — not first-line treatment.
Gionchetti P et al. Gastroenterology. 2000;119(2):305-9. PMID 10930365. DOI: 10.1053/gast.2000.9370
Randomised, double-blind, placebo-controlled trial in 362 women with IBS. Three doses of B. infantis 35624 (now marketed as Alflorex in the UK) were compared against placebo over 4 weeks. The 1×10⁸ CFU dose significantly improved the IBS composite primary endpoint score and individual symptoms including abdominal pain, bloating, bowel urgency, and straining. Higher doses (1×10⁶ and 1×10¹⁰) were not superior.
This remains the most cited single-strain IBS RCT for a UK-available product. Limitations: all-female population, 4-week duration, and the study was industry-funded (Procter & Gamble, who held the Bifantis licence).
Whorwell PJ et al. Am J Gastroenterol. 2006;101(7):1581-90. PMID 16863564. DOI: 10.1111/j.1572-0241.2006.00734.x
Randomised, double-blind, placebo-controlled trial in 147 patients with mild-to-moderately active ulcerative colitis. Patients received the formulation (as VSL#3) at 3,600 billion CFU/day or placebo as adjunctive to standard treatment for 12 weeks. Response rates were significantly higher in the active group (32.5% vs 10%; p=0.001).
This trial used a higher dose (3,600B CFU) than the standard 450B sachet dose studied in pouchitis. This distinction matters when comparing trial data to the retail product.
Sood A et al. Clin Gastroenterol Hepatol. 2009;7(11):1202-9. PMID 19631292. DOI: 10.1016/j.cgh.2009.07.001
Randomised, double-blind, placebo-controlled trial in 186 IBS patients. Participants received Symprove or placebo for 12 weeks. The Symprove group showed significant improvements in IBS Symptom Severity Score (IBS-SSS) vs placebo. This is the only published independent RCT for the Symprove formulation.
The trial has not been independently replicated at scale, limiting the strength of the evidence. The IBS-SSS improvements were statistically significant but the clinical meaningfulness of the effect size is debated. Symprove's CFU count per serving is considerably lower than high-potency sachet-format probiotics.
Sisson G et al. BMJ Open Gastroenterol. 2014;1(1):e000014. DOI: 10.1136/bmjgast-2014-000014
The clinical evidence base for probiotics — including the De Simone Formulation and B. infantis 35624 — is predominantly derived from populations with diagnosed gastrointestinal conditions: IBD, IBS, pouchitis, and antibiotic-associated diarrhoea. Evidence for benefit in otherwise healthy UK adults without these conditions is limited.
The NHS states on its probiotics page that "there's little evidence to suggest that taking probiotic supplements provides the same benefits to healthy people." This does not mean probiotics are ineffective for healthy people — it means the RCT evidence base was not built in that population.
NHS. Probiotics. nhs.uk/tests-and-treatments/probiotics/. Accessed June 2026.
The clinical research discussed in this article describes the De Simone Formulation as studied in specific clinical populations. It should not be read as a claim that CDS22-formula treats any condition. CDS22-formula is a food supplement, not a medicine. No authorised UK health claim is made on this page or on the product.
CDS22-formula — The Original De Simone Formulation
8 strains · 450 billion CFU per sachet · Refrigerated and cold-chain delivered across the UK. The formulation behind over 200 scientific publications.
Probiotic.co.uk · Authorised UK retailer · Cold-chain: Easi-Chill packs + foil liner · Not a medicine · 20% VAT included · Dispatched Mon–Thu
Product details on this page — including dose (450 billion CFU per sachet), format (12 sachets of 4.4g), NCIMB strain codes, GTIN (8055039380144), and price (£19.50 inc. 20% VAT) — were verified by Probiotic.co.uk from current CDS22-formula packaging and supplier documentation, June 2026. Product details should always be checked against the current label before use, as formulations and pricing may change.
Frequently asked questions
What is a clinical-grade probiotic?
A clinical-grade probiotic is a supplement whose specific bacterial strains — identified by NCIMB, ATCC, or DSM codes — have been studied in published human randomised controlled trials. It is not a regulatory classification in the UK. A product with published RCTs and coded strains has more verifiable evidence than one without, regardless of CFU count.
Which probiotic has the most clinical evidence in the UK?
The De Simone Formulation — sold in the UK as CDS22-formula — has one of the most extensive published evidence bases of any probiotic available to UK consumers, referenced in over 200 scientific publications and more than 80 clinical studies. It is the only probiotic named in the AGA 2024 pouchitis guideline (Barnes et al., PMID 38128971). Alflorex (B. infantis 35624) has strong evidence for IBS-D specifically (Whorwell et al., PMID 16863564).
Is Symprove clinically evidenced?
Symprove has one published RCT — Sisson et al. (BMJ Open Gastroenterology, 2014) — in IBS patients, showing statistically significant IBS symptom score improvements vs placebo over 12 weeks. The evidence base is smaller than that of CDS22-formula or Alflorex, and the trial has not been independently replicated at scale.
Does CFU count determine how good a probiotic is?
No. Strain identity and evidence alignment to your situation matter more than CFU count. The pivotal Alflorex IBS trial used 1×10⁸ CFU per day — 1 billion — and found significant improvement. Higher doses in that study did not outperform the lowest dose tested. CFU is not a proxy for efficacy.
What are the signs that probiotics are working?
Signs that probiotics are working typically include reduced bloating or gas, more regular bowel movements, and improved stool consistency — usually appearing within 2–4 weeks of consistent daily use. Some people experience a temporary increase in gas in the first 1–2 weeks as the gut microbiota adjusts. If symptoms worsen significantly or persist beyond 4 weeks, a GP should be consulted.
Is CDS22-formula the same as VSL#3 or Vivomixx?
CDS22-formula contains the original 8-strain De Simone Formulation, which was sold under the VSL#3 brand until 2016 and as Vivomixx (Mendes SA) until 2025. Per the ECCO October 2023 official statement, the product currently sold as VSL#3 no longer contains the De Simone Formulation. Most pre-2016 VSL#3 studies relate to the formulation now supplied as CDS22-formula. CDS22-formula has no affiliation with the VSL#3 or Vivomixx brands.
Are probiotics legal in the UK?
Yes. Probiotics are sold legally in the UK as food supplements, regulated by the Food Standards Agency (FSA). They are not medicines and do not require a prescription. No authorised health claims for probiotics have been approved under retained UK food supplement law, so compliant products do not make disease treatment claims. UK supplement VAT is 20%.
Where can I buy CDS22-formula in the UK?
CDS22-formula (450 billion CFU, 12 sachets, £19.50) is available from Probiotic.co.uk — the authorised UK retailer for the De Simone Formulation. Orders are dispatched cold-chain with Easi-Chill coolant packs and insulated foil liners, via Royal Mail Tracked 24 or DPD Premium Tracked, Monday to Thursday. 20% VAT is included in the listed price.
How long should I take probiotics?
Duration depends on the reason for use. Published RCTs for the De Simone Formulation in pouchitis maintenance used daily supplementation for up to 12 months (Gionchetti et al., PMID 10930365). Alflorex IBS trials ran for 4 and 12 weeks. For general gut support in healthy adults, no established optimal duration exists. Speak to a GP if you have an ongoing health condition before starting any supplement.
Is Alflorex the same as CDS22-formula?
No. Alflorex contains a single strain — Bifidobacterium longum subsp. infantis 35624 — studied primarily in IBS-D. CDS22-formula contains 8 strains at 450 billion CFU and has its strongest evidence in IBD and pouchitis contexts. These are entirely different products with different evidence profiles for different populations.
- A clinical probiotic is a supplement whose specific bacterial strains have been studied in published human RCTs — not a UK regulatory classification.
- The De Simone Formulation (CDS22-formula) is the only probiotic named in the AGA 2024 clinical practice guideline for pouchitis prevention (Barnes et al., Gastroenterology, PMID 38128971).
- CDS22-formula contains 8 strains (NCIMB-coded) at 450 billion CFU per sachet — the dose and formulation used in published IBD and pouchitis trials.
- B. infantis 35624 (Alflorex) showed significant improvement in IBS composite symptom scores at 1×10⁸ CFU/day in Whorwell et al. (Am J Gastroenterol, 2006, PMID 16863564) — higher doses were not superior.
- CFU count is not a proxy for efficacy — strain identity and evidence alignment to the clinical situation matter more.
- Signs probiotics are working: reduced bloating, more regular bowel movements, improved stool consistency — typically within 2–4 weeks.
- The current VSL#3 product does not contain the De Simone Formulation, per the ECCO October 2023 official statement. CDS22-formula does.
- Evidence for probiotics in otherwise healthy adults without a diagnosed GI condition is limited — most RCT data comes from IBD, IBS, and pouchitis populations.
- In the UK, all probiotic supplements are regulated by the FSA as food supplements — not medicines. No prescription is required. VAT is 20%.
- CDS22-formula (8 strains, 450B CFU, £19.50 / 12 sachets) is available from Probiotic.co.uk with nationwide cold-chain delivery across the UK.
Related articles
References
- Whorwell PJ et al. Efficacy of an encapsulated probiotic Bifidobacterium infantis 35624 in women with irritable bowel syndrome. Am J Gastroenterol. 2006;101(7):1581-90. PMID 16863564. — pubmed.ncbi.nlm.nih.gov/16863564
- Gionchetti P et al. Oral bacteriotherapy as maintenance treatment in patients with chronic pouchitis. Gastroenterology. 2000;119(2):305-9. PMID 10930365. — pubmed.ncbi.nlm.nih.gov/10930365
- Barnes EL et al. AGA Clinical Practice Guideline on the Role of Probiotics in the Management of Gastrointestinal Disorders. Gastroenterology. 2024;166(1):59-85. PMID 38128971. — pubmed.ncbi.nlm.nih.gov/38128971
- Mimura T et al. Once daily high dose probiotic therapy (VSL#3) for maintaining remission in recurrent or refractory pouchitis. Gut. 2004;53(1):108-14. PMID 14684584. — pubmed.ncbi.nlm.nih.gov/14684584
- Sood A et al. The probiotic preparation VSL#3 induces remission in patients with mild-to-moderately active ulcerative colitis. Clin Gastroenterol Hepatol. 2009;7(11):1202-9. PMID 19631292. — pubmed.ncbi.nlm.nih.gov/19631292
- Tursi A et al. Treatment of relapsing mild-to-moderate ulcerative colitis with the probiotic VSL#3 as adjunctive to a standard pharmaceutical treatment. Am J Gastroenterol. 2010;105(10):2218-27. PMID 20517305. — pubmed.ncbi.nlm.nih.gov/20517305
- Halkjaer SI et al. Probiotics during pregnancy and breastfeeding — Vivomixx. Curr Dev Nutr. 2020;4(8):nzaa107. PMID 32617453. — pubmed.ncbi.nlm.nih.gov/32617453
- Sisson G et al. Randomised clinical trial: a liquid multi-strain probiotic vs. placebo in the irritable bowel syndrome — a 12 week double-blind study. BMJ Open Gastroenterol. 2014;1(1):e000014. — doi.org/10.1136/bmjgast-2014-000014
- UK Food Standards Agency. Food supplements guidance. food.gov.uk. — food.gov.uk/business-guidance/food-supplements
- NHS. Probiotics. nhs.uk/tests-and-treatments/probiotics/. — nhs.uk/tests-and-treatments/probiotics