Saccharomyces Boulardii Probiotics: What to Check on the Label

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Updated Oct 2026: label, price and research checked on Oct 22, 2026.

If you want a probiotic with a short, clean ingredient list, Pure TheraPro Rx Saccharomyces Boulardii is my pick.

Why I like the label

Many probiotics pack billions of CFU of bacterial strains alongside fillers like potato starch, acacia fiber, gellan gum and magnesium stearate. Pure TheraPro keeps it simple:

• One ingredient: Saccharomyces boulardii (the Lynside® strain CNCM I-3799), 10 billion CFU per 2-capsule serving (500 mg)
• One “other ingredient”: hypromellose (HPMC), a plain plant-based capsule
• Shelf-stable: no refrigeration needed, stable for 24 months at room temperature
• Non-GMO, made in the USA; the maker says it follows FDA cGMP rules and is independently audited or certified to standards including NSF/ANSI 455-2 GMP

Suggested use on the label is 2 capsules once or twice a day.

What makes S. boulardii different

S. boulardii is a yeast, not a bacterium. Antibiotics target bacteria, which is one reason researchers often study it alongside an antibiotic course.

What the research says, in plain terms:

• Antibiotic research. Much of the published research on S. boulardii looks at people taking antibiotics, and most of it used a different strain (see the caveat below). I don’t treat it as a reason to buy this product.
• Gut lining. A 2019 review of how S. boulardii interacts with the intestinal barrier mixes lab, animal and human studies of the I-745 strain, and it received research funding from that strain’s maker. Interesting, but early.

An honest caveat on the strain. Most of the big human studies used a different S. boulardii strain, CNCM I-745 (the one sold as Florastor). Pure TheraPro uses Lesaffre’s CNCM I-3799. In 2012, Europe’s food-safety agency ruled there wasn’t enough evidence to treat the two strains as identical. Since then, the main human trial of CNCM I-3799 I found was a 2020 study of 100 young children, and several of its authors work for the strain’s maker. So the strain in my pick has less independent human research behind it than Florastor’s. I still prefer Pure TheraPro for the cleaner label and price, but you should know the tradeoff.

Bloating and tolerance

In my experience, a single-strain yeast is easier to tolerate than big multi-strain bacterial blends. That’s my opinion, not a proven fact; everyone’s gut is different. If something doesn’t agree with you, stop and talk to your doctor.

Who should skip it or ask first

S. boulardii is generally well tolerated, but there are rare reports of the yeast getting into the bloodstream (fungemia). A 2023 systematic review found the most common risk factors were intensive care stays and feeding tubes or IV nutrition, mostly in seriously ill hospital patients. The manufacturer says not to use it if you have severe immune suppression. Talk to your doctor first if you take medication, are pregnant or nursing, or are giving it to a child. If you take an antifungal, space them at least 2 hours apart.

Cost

• Pure TheraPro’s own site: $18.97 for 60 capsules (one-time purchase). At the minimum serving of 2 capsules a day, that’s a 30-day supply, about 63¢ a day. The 120-count is $28.97 (about 48¢ a day) and the 240-count is $44.97 (about 37¢ a day).
• Amazon: sold in 60, 120 and 240 capsule bottles. The 240-count was $45.97 when I checked (about 38¢ a day at 2 capsules). Either way, the 240-count bottle is the cheapest per day. Prices change often.

You can check out Pure TheraPro Rx Saccharomyces Boulardii here on Amazon.

Bottom line

If you’re tired of probiotics full of fillers, this single-strain yeast with nothing but a veggie capsule is a smart, clean choice. Just know the research caveat above, and run it by your doctor.

Ready to try it? Grab Pure TheraPro Rx Saccharomyces Boulardii on Amazon here.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Not medical advice; talk to your doctor.

Sources (accessed Oct 22, 2026)

• Pure TheraPro, Saccharomyces Boulardii product page (price, servings, safety notes, GMP): https://purethera.com/products/saccharomyces-boulardii (accessed 2026-10-22)
• Amazon listing B09BDJ87L6 (240-count variant: ingredients, directions, price, sizes): https://www.amazon.com/dp/B09BDJ87L6 (accessed 2026-10-22)
• Terciolo C, Dapoigny M, Andre F. Beneficial effects of Saccharomyces boulardii CNCM I-745 on clinical disorders associated with intestinal barrier disruption. Clin Exp Gastroenterol. 2019. PMID 30804678. https://pmc.ncbi.nlm.nih.gov/articles/PMC6375115/ (doi:10.2147/CEG.S181590) (accessed 2026-10-22)
• EFSA NDA Panel. Scientific Opinion on S. cerevisiae var. boulardii CNCM I-3799 and reducing gastro-intestinal discomfort. EFSA J. 2012;10(7):2801. https://doi.org/10.2903/j.efsa.2012.2801 (PMID 42016124) (accessed 2026-10-22)
• Vinayagamoorthy K, et al. Epidemiology of Saccharomyces fungemia: a systematic review. Med Mycol. 2023. PMID 36806741. https://doi.org/10.1093/mmy/myad014 (accessed 2026-10-22)