Lactobacillus casei vs Saccharomyces boulardii
Two forms of the same compound. What differs is how much of it your body absorbs, how well you tolerate it and what it costs per month.
Side by side
Green marks the better value| Lactobacillus casei | Saccharomyces boulardii | |
|---|---|---|
| Bioavailability | 85% | 80% |
| Safety rating | 10/10 | 9/10 |
| Cost per month | $25 | $40 |
| Daily dose | 1-20 billion CFU | 250-500mg |
| Best timing | With meals daily | With meals or during antibiotics |
| Evidence level | A | A |
Verdict
Lactobacillus casei wins on 3 of the measurable metrics.
It absorbs at 85% against 80%, which is the number that decides how much of the dose actually reaches you.
What actually differs
Lactobacillus casei
Versatile probiotic bacteria that supports digestive health, immune function, and may help regulate inflammatory responses and improve cholesterol levels
- Long research history
- Good survival
- Immune benefits
- Commercial availability
- Moderate adherence
- Limited specialty strains
- Quality variations
- Temperature sensitive
Saccharomyces boulardii
Beneficial probiotic yeast that supports digestive health, prevents antibiotic-associated diarrhea, and enhances immune function with unique resistance to antibiotics
- Antibiotic resistance
- Clinical validation
- Pathogen protection
- Immune support
- Higher cost
- Fungemia risk in immunocompromised
- Transient effects
- Heat sensitive
How these numbers are read
- Bioavailability is the share of the dose that reaches your bloodstream — the single most useful number when choosing a form.
- Safety rating reflects tolerance at normal doses, not toxicity risk.
- Cost is per month at the typical daily dose, so a cheaper form taken at double the dose is not cheaper.
- Evidence level A means the form itself was studied, not just the parent compound.
Where to buy
Both forms deliver the same compound — pick by the numbers above, then check the label matches.
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Common questions
Which is better, Lactobacillus casei or Saccharomyces boulardii?
Lactobacillus casei absorbs better — 85% against 80%. Absorption decides how much of the dose actually reaches you, so it usually matters more than the milligrams printed on the label.
What is the difference between Lactobacillus casei and Saccharomyces boulardii?
Both deliver the same active compound. They differ in how well the body takes them up, how they are tolerated and what a month costs: $25 against $40.
Can you take Lactobacillus casei and Saccharomyces boulardii together?
You can, but there is rarely a reason to. Two forms of the same compound stack the same active dose, so the usual approach is to pick the better absorbed one and dose it properly.