Saccharomyces boulardii — Sources & Sourcing
Where to buy S. boulardii — and how to be sure you're getting the clinically-validated strain, not a generic look-alike. The trust question here isn't heavy metals; it's strain identity and viable CFU.
For what it does, see its role in the Deworming Protocol and Gut Reset. This page is purely about sourcing.
- It's a yeast, not a bacterium — a strain of Saccharomyces cerevisiae var. boulardii. This is why it's the probiotic used during antimicrobial/antiparasitic kill phases: antibiotics and antiparasitics don't kill yeast, so it survives to suppress Candida overgrowth and protect native flora.
- The strain that matters: CNCM I-745 — manufactured solely by Biocodex (a French company). 65+ years of use, 100+ clinical trials.
- Protocol dose: 250 mg 2×/day (≈5 billion CFU per 250 mg).
Bottom line up front
- You do not need to import "Florastor" from the US. Florastor is just the US brand name for Biocodex's CNCM I-745. The identical strain is sold across the UK and EU under other Biocodex brands — and Florastor itself is on Amazon.co.uk.
- Fastest UK route: order Florastor or Enterol (both CNCM I-745, 250 mg) on Amazon.co.uk / a UK pharmacy → next-day/2-day. No US import, no strain compromise.
- The only thing to verify: that "CNCM I-745" is printed on the label (see checklist).
The key insight: one strain, many brand names
The "only one manufacturer" claim your source made is true — but the manufacturer is Biocodex (France), present in 100+ countries. "Florastor" is only the American label. The same CNCM I-745 strain is sold worldwide:
| Brand | Region | Strain | Format / dose |
|---|---|---|---|
| Florastor | US — also on Amazon.co.uk | ✅ CNCM I-745 | Capsules, 250 mg |
| Enterol | UK / EU (Biocodex) | ✅ CNCM I-745 | Caps / sachets, 250 mg |
| Ultra-Levure | France / Belgium (OTC in pharmacies) | ✅ CNCM I-745 | Caps / sachets, ~200 mg |
| Ultra-Levura · Bioflor · Bioflora · Floratil · Biodermine | worldwide | ✅ CNCM I-745 | various |
So the "US-only" problem was really a brand-name problem, not a strain-availability problem.
What "trust" means for a probiotic (it's not heavy metals)
Unlike the peptides, these are legitimate over-the-counter supplements — and Enterol/Ultra-Levure are registered medicines in much of the EU. The verification questions are different:
- Strain identity — is it actually CNCM I-745, or an unspecified "S. boulardii"? Generic listings often don't say. If the strain code isn't on the label, you can't assume it's the studied one.
- Viable CFU at end of shelf life — not just "at time of manufacture." Reputable brands guarantee the count to expiry.
- Stability / storage — CNCM I-745 is lyophilised and shelf-stable (no fridge needed), which is part of why it travels and stores well.
- Authenticity — buy from the brand, a pharmacy, or a reputable retailer; avoid grey third-party marketplace sellers with broken cold-chain or near-expiry stock.
Sources — the validated strain (CNCM I-745) 🟢
All legitimate OTC supplements/registered medicines. Prices are indicative — verify live; one 250 mg cap = one protocol dose (take 2/day).
| Source | 🚦 | Ships / buy | Format | ≈ Price | ≈ /dose (250 mg) | UK / FR |
|---|---|---|---|---|---|---|
| Florastor (Amazon.co.uk) | 🟢 | Amazon Prime → next-day | 250 mg caps | ~£20–28 / ~50 caps | ~£0.45 | ✅ UK, fast |
| Enterol (Biocodex) | 🟢 | UK pharmacies / Elivera / iHerb | 250 mg caps or sachets | ~£10–16 / 30–50 | ~£0.30 | ✅ UK + EU |
| Ultra-Levure (Biocodex) | 🟢 | French pharmacies, OTC | ~200 mg caps/sachets | ~€5–8 / 20–30 | ~€0.25 | ✅ FR (walk-in) |
Reading this for your situation (5 days, then travelling)
- UK, before you fly: Florastor or Enterol on Amazon.co.uk — CNCM I-745, next-day/2-day, done. Enterol is usually the cheaper of the two for the same strain + dose.
- In France on holiday: walk into any pharmacie and ask for Ultra-Levure — same strain, over the counter, a few euros.
Other strains — honest comparison
| Strain / brand | 🚦 | Notes |
|---|---|---|
| CNCM I-745 (Florastor/Enterol/Ultra-Levure) | 🟢 | The evidence base. ~all major RCTs & meta-analyses (AAD, C. diff, H. pylori, Candida suppression, paediatric gastroenteritis) use this strain. Matches the protocol. |
| CNCM I-1079 (Optibac "Saccharomyces boulardii") | 🟢 | Different strain (Lallemand / Institut Rosell), 5 bn CFU/cap. UK's most-recommended brand, widely stocked (Boots, H&B, Amazon). Legitimate and researched — but far less studied for these specific uses. A reasonable fallback, not the protocol strain. |
| Generic "S. boulardii" (unspecified strain) | 🟡 | No strain code = unknown provenance. Effects plausibly similar at species level (it's the same yeast), but you're not buying the validated data. Avoid when CNCM I-745 is this easy to get. |
Are other strains "as effective"?
- Species-level, most S. boulardii preparations share the core properties — it's a yeast, so it survives the kill phase and antagonises Candida regardless of strain.
- Strain-level, the clinical proof sits almost entirely with CNCM I-745. That's what you're paying the small premium for.
- Practical verdict: since CNCM I-745 is available in the UK (Florastor/Enterol) and OTC in France (Ultra-Levure), there's no reason to gamble on an unspecified strain. If — and only if — I-745 were unavailable, Optibac's CNCM I-1079 is the most credible substitute (a real, researched strain), well ahead of a no-name generic.
Verification checklist
Before you buy any S. boulardii
- [ ] Label explicitly says "CNCM I-745" (or a known Biocodex brand: Florastor / Enterol / Ultra-Levure).
- [ ] 250 mg per capsule (≈5 bn CFU) to match the protocol dose (take 2/day).
- [ ] CFU guaranteed to end of shelf life, not just at manufacture.
- [ ] In-date, and (for marketplace sellers) sold by the brand or a reputable pharmacy — not near-expiry grey stock.
- [ ] Fallback only if I-745 unavailable: Optibac CNCM I-1079 (named strain) over any unnamed generic.
Caveats
- Prices/stock as researched July 2026 — verify live before ordering; the point of this page is strain and route, not exact pricing.
- Enterol / Ultra-Levure are registered medicines in parts of the EU; Florastor is sold as a supplement. Same strain, different regulatory label.
- Keep it lyophilised and in-date; CNCM I-745 is shelf-stable, but heat/humidity still degrade CFU over time.
- During a kill phase, run it throughout and pair with a broad-spectrum probiotic timed apart (per the Deworming Protocol).
- Not medical advice.