Skip to main content
Evidence-Based Supplement Research
Evidence-Based Supplement Research
Pillser
Search
Sign UpLog In

Lactobacillus reuteri

What does the research say about Lactobacillus reuteri?

4 health outcomes synthesised

Lactobacillus reuteri has been studied for four oral health outcomes, primarily in populations with periodontitis. The strongest evidence area is for reducing bleeding on probing (BOP), with 5 studies showing a predominantly beneficial direction, though the overall evidence strength is low. Across outcomes, the most consistent effective dose range is 1×10⁹ CFU/day, typically administered as one lozenge taken once or twice daily, with study durations ranging from 14 days to 12 months.

Strongest evidence: No outcomes reached high or moderate evidence strength. The most researched outcome, reduced bleeding on probing (BOP), had the largest number of studies (5) and showed a predominantly beneficial direction (3 of 5 studies beneficial), but the evidence strength is rated as low due to small sample sizes and mixed results. The effective dose range identified was 1–2 lozenges per day.

Mixed or weaker evidence: Three other outcomes—improved clinical attachment (4 studies), reduced probing depth (3 studies), and reduced plaque index (3 studies)—all have low evidence strength with mixed results. For improved clinical attachment, 2 of 4 studies reported benefit, but 1 reported harm in diabetic patients and 1 found no effect. For reduced probing depth, only 1 of 3 studies showed a large beneficial effect, while 2 longer studies (180 days) in diabetic patients found no benefit. For reduced plaque index, 2 of 3 studies showed small-to-moderate benefit, but the highest-quality study found no significant effect.

Effective dose patterns: Across outcomes, the most common effective dose was 1×10⁹ CFU/day or one lozenge taken 1–2 times daily, particularly for clinical attachment and probing depth. Studies using lozenges for 14 days to 12 months showed effects, but longer studies (180 days) in diabetic populations often yielded neutral results.

Population insights: Most studies focused on patients with periodontitis or gingivitis, with some including diabetic patients or adolescents with betel quid chewing habits. Neutral or harmful results were more common in diabetic populations, suggesting that L. reuteri may not benefit patients with diabetes and periodontitis, or may even worsen outcomes in that group.

Notable caveats: The evidence base is small across all outcomes (3–5 studies per outcome), and conclusions should be considered preliminary. Many individual studies did not reach statistical significance, and some of the highest-quality RCTs showed neutral or harmful effects, indicating that the overall effect may be smaller or less consistent than the predominant direction suggests. No outcomes achieved moderate or high evidence strength.

Frequently asked

  • What is Lactobacillus reuteri good for according to research?
    Research on Lactobacillus reuteri has focused on four oral health outcomes: reducing bleeding on probing (BOP), improving clinical attachment, reducing probing depth, and reducing plaque index. The strongest evidence is for reducing BOP, where 3 of 5 studies reported benefit, but the overall evidence strength is low. All outcomes are preliminary and should not be considered conclusive.
  • What dose of Lactobacillus reuteri is typically used in studies?
    The most common dose across studies is 1×10⁹ CFU per day, typically administered as 1–2 lozenges taken daily. Study durations ranged from 14 days to 12 months, with a median duration of about 101–180 days depending on the outcome.
  • Who benefits most from Lactobacillus reuteri?
    Most studies focused on patients with periodontitis or gingivitis, with some including adolescents with betel quid chewing habits. However, results in diabetic patients with periodontitis were less favorable: in one study on clinical attachment, diabetic patients experienced harm, and in two studies on probing depth, diabetic patients showed no benefit. This suggests that nondiabetic periodontitis patients may be more likely to benefit, though the evidence is still limited.
  • Are there caveats or limitations in the research on Lactobacillus reuteri?
    Yes, all four outcomes have low evidence strength, meaning the findings are preliminary. The evidence base is very small (3–5 studies per outcome), and many individual studies did not reach statistical significance. Some of the highest-quality RCTs (e.g., 2024 and 2025 studies) found neutral or harmful results, indicating the effect may not be consistent across all populations.
  • Does Lactobacillus reuteri help reduce bleeding on probing?
    Across 5 studies, 3 reported beneficial effects on reducing bleeding on probing, with 2 showing moderate or large effect sizes. However, the evidence is mixed: 2 studies found neutral results, and many studies did not reach statistical significance. The evidence strength is rated as low, so this effect should be considered preliminary.
  • Does Lactobacillus reuteri improve clinical attachment in periodontitis patients?
    The evidence is mixed: 2 of 4 studies found moderate beneficial effects on clinical attachment, but 1 study reported harm in diabetic patients and 1 systematic review found no significant benefit. The effective dose was 1×10⁹ CFU/day for 56–118 days, but the low evidence strength and conflicting results mean this outcome remains uncertain.

Most-studied combinations with Lactobacillus reuteri

most supplement research is combination research
Also studied with:Lactobacillus reuteri ATCC PTA 5289 (2)
Back to top