The Best-Researched Ingredients for Oral Health

How we ranked these ingredients

This guide ranks ingredients, not brands, by the strength and relevance of human evidence for teeth, gums and breath. We gave more weight to randomized controlled trials and systematic reviews, and we note when results come from a specific strain, a mouthwash or gel, or use alongside professional dental treatment. We only included ingredients that have a page on CapsReview. None of these replaces brushing twice daily with fluoride toothpaste, cleaning between teeth and regular dental care.

1. Lactobacillus reuteri

What it is: a probiotic bacterium found in the gut and mouth. What studies show: in a one-year randomized trial, L. reuteri lozenges after deep cleaning improved plaque, bleeding and pocket depth compared with placebo, and a meta-analysis found short-term benefits as an adjunct to periodontal therapy. For gingivitis alone, a 2020 meta-analysis found the evidence weak. Typical studied dose: specific strains in lozenges or gum, once or twice daily. Cautions: avoid without medical advice if immunocompromised. Read more about Lactobacillus reuteri.

2. Bifidobacterium lactis

What it is: a widely used probiotic species with many commercial strains. What studies show: the HN019 strain, in lozenges twice daily for 30 days after scaling and root planing, improved pocket depth and attachment in a randomized trial of 41 patients, and lowered plaque and bleeding in a second small trial. Other strains, such as BL-04, have been studied mainly for colds. Typical studied dose: HN019 lozenges twice daily. Cautions: results are strain-specific. Read more about Bifidobacterium lactis.

3. Xylitol

What it is: a sugar alcohol that cavity bacteria cannot ferment. What studies show: a Cochrane review of 10 studies found low-quality evidence that fluoride toothpaste with 10% xylitol may reduce cavities by about 13% in children compared with fluoride toothpaste alone, and insufficient evidence for other xylitol products. A 2024 review could not confirm a preventive effect. Typical studied dose: gram amounts spread through the day, or 10% in toothpaste. Cautions: can cause gas or loose stools; toxic to dogs. Read more about xylitol.

4. Peppermint and essential oils

What it is: menthol-rich peppermint is one of several essential oils used in antiseptic mouthrinses. What studies show: a meta-analysis of 29 long-term trials found that essential oil mouthrinses added to brushing and flossing increased healthy gum and plaque-free sites, and an independent review found lower plaque and gingivitis scores. These results apply to rinses with a specific multi-oil formula, not to peppermint in a tablet. Typical studied dose: rinse twice daily. Cautions: oral peppermint oil can cause heartburn. Read more about peppermint.

5. Turmeric (curcumin)

What it is: the yellow spice and its main compound, curcumin. What studies show: curcumin mouthwashes performed comparably to chlorhexidine for plaque and gum inflammation in a meta-analysis of six trials, and curcumin gels or rinses as adjuncts to deep cleaning performed similarly to chlorhexidine in a meta-analysis of nine trials. Evidence quality was low, and swallowed turmeric has not been tested for gums. Typical studied dose: local mouthwash or gel. Cautions: liver injury reported with high-bioavailability supplements; may be unsafe in pregnancy. Read more about turmeric.

6. Streptococcus salivarius

What it is: a normal tongue and throat bacterium; strains K12 and M18 are sold for breath. What studies show: probiotics including S. salivarius improved breath odor scores in the short term in a 2022 meta-analysis, but a small K12 trial found no difference from placebo when the tongue was not cleaned first. Typical studied dose: one K12 lozenge daily for a few weeks. Cautions: persistent bad breath needs a dental check. Read more about Streptococcus salivarius.

7. Lactobacillus paracasei

What it is: a common probiotic species. What studies show: the SD1 strain reduced cavity-linked bacteria and new cavities in high-risk children in a six-month trial, but the F19 strain showed no long-term effect in an infant study. Adult dental evidence is thin. Typical studied dose: strain-specific, daily for months. Cautions: avoid without medical advice if immunocompromised. Read more about Lactobacillus paracasei.

8. Zinc

What it is: an essential mineral. What studies show: zinc compounds are used in toothpastes and mouthwashes for plaque and odor control, as described in a review of oral care ingredients; that is a topical use. We found no good evidence that swallowed zinc supplements improve gums. Typical studied dose: in oral care products, not capsules. Cautions: adult upper limit is 40 mg a day, and long-term high intake can cause copper deficiency, according to the NIH Office of Dietary Supplements. Read more about zinc.

9. Calcium

What it is: the main structural mineral in bones and teeth. What studies show: calcium is essential, but in a survey of 6,150 adults, calcium intake was not significantly associated with gum disease. Small amounts in dental supplements are unlikely to matter. Typical studied dose: the adult RDA is 1,000 to 1,200 mg a day from all sources. Cautions: excess supplemental calcium may raise kidney stone risk and can interfere with some medicines, per the NIH Office of Dietary Supplements. Read more about calcium.

Ingredients that did not make the list

Several ingredients common in oral health supplements have no human oral health evidence we could find, including chlorophyllin (which failed to reduce garlic breath in one study), shilajit, boron, milk thistle, artichoke, chanca piedra and yarrow. Some have evidence for other uses, but not for teeth, gums or breath.

The takeaway

The best-researched options act locally in the mouth: specific probiotic strains in lozenges, xylitol in gum or toothpaste, and essential oil or curcumin rinses. Swallowed herbs and minerals have little support for oral health. Talk to your dentist before adding any of them, and keep the basics, fluoride toothpaste, daily cleaning between teeth and regular checkups, at the center of your routine.