Oral Probiotics for Halitosis in Healthy Adults

Efficacy of Oral Probiotics on Cysteine-Induced Halitosis in Healthy Adult Volunteers.

The aim of this study is to evaluate efficacy of a probiotic lozenge containing BLIS M18, BLIS K12 and a prebiotic in healthy adults.

Study Overview

• Status: Not yet recruiting
• Conditions: Halitosis
• Intervention / Treatment: Dietary supplement: In this study, a probiotic lozenge formulation containing S. salivarius K12, M18 and prebiotic will be evaluated for its potential to improve bad breath; Other: Placebo

Detailed Description

This is a double-blind, randomized controlled colonization pilot study with no crossover to evaluate the efficacy of probiotic lozenges on halitosis in healthy adults.

Participants will be randomly assigned to 2 groups consuming probiotic lozenge containing Streptococcus salivarius M18 and K12 and with prebiotic over a 13 day period. Breath scores will be measured at predetermined time points pre and post intervention.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: John D Hale, PhD; Phone Number: +6434740988; Email: john.hale@blis.co.nz
• Study Contact Backup: Name: Rohit Jain, PhD; Phone Number: +6434740988; Email: rohit.jain@blis.co.nz

Study Locations

• New Zealand
  • Otago
    • Dunedin, Otago, New Zealand, 9012
      • Blis Technologies Ltd

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Participants should be otherwise healthy,
• practice good oral hygiene,
• 18 - 70 years of age

Exclusion Criteria:

• on antibiotic therapy,
• immunocompromised (have a weakened immune system)
• history of autoimmune disease,
• allergy or sensitivity to dairy,
• have an active periodontal disease, any known allergy or sensitivity to components of the test product or cysteine solution.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Oral probiotic lozenges; Oral probiotic lozenges containing Streptococcus salivarius M18 and Streptococcus salivarius K12 and prebiotic	Dietary supplement: In this study, a probiotic lozenge formulation containing S. salivarius K12, M18 and prebiotic will be evaluated for its potential to improve bad breath; In this study, a probiotic-free lozenge formulation containing S. salivarius K12, M18 and prebiotic will be evaluated for its potential to improve bad breath as a comparator.
Placebo Comparator: Placebo lozenges; Oral lozenges	Other: Placebo; Probiotic free placebo lozenge

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of Volatile Sulphur Compounds in ppb between the active and placebo groups	Study will determine the change in Volatile Sulphur Compounds (VSCs) as measured in ppb, following application of probiotic lozenges containing Streptococcus salivarius K12, Streptococcus salivarius M18 and prebiotic compared with a placebo lozenge. Statistical analysis (e.g. Students t-test) will be carried out to compare the participants data from baseline to post cysteine mouthrinse before the lozenge application and 13 days after once a day lozenge application with the level of significance of p≤0.05 across the probiotic and placebo lozenge. Appropriate statistical analysis software (e.g. Microsoft Excel) will be used to analyse the data	13 days

Collaborators and Investigators

• Sponsor: John Hale
• Investigators: Principal Investigator: John R Tagg, PhD, Blis Technologies Ltd

Publications and helpful links

General Publications

• Burton JP, Drummond BK, Chilcott CN, Tagg JR, Thomson WM, Hale JDF, Wescombe PA. Influence of the probiotic Streptococcus salivarius strain M18 on indices of dental health in children: a randomized double-blind, placebo-controlled trial. J Med Microbiol. 2013 Jun;62(Pt 6):875-884. doi: 10.1099/jmm.0.056663-0. Epub 2013 Feb 28.

Study record dates

Study Major Dates

• Study Start (Estimated): March 15, 2026
• Primary Completion (Estimated): June 15, 2026
• Study Completion (Estimated): July 15, 2026

Study Registration Dates

• First Submitted: January 25, 2026
• First Submitted That Met QC Criteria: January 25, 2026
• First Posted (Actual): February 3, 2026

Study Record Updates

• Last Update Posted (Actual): February 4, 2026
• Last Update Submitted That Met QC Criteria: February 2, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: chewable tablet; Streptococcus salivarius M18; halitosis; Streptococcus salivarius K12; oral probiotic
• Additional Relevant MeSH Terms: Signs and Symptoms, Digestive; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Halitosis
• Other Study ID Numbers: BLTCT2025/1; 2025EXP24497 (Other Identifier: Health and Disabilities Ethics Committee MOH Wellington NZ)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Data and information included in the Protocol and Clinical Study Report will be shared to other researchers and/or in publications in due course.
• IPD Sharing Time Frame: Study report 3 months after the completion of the study
• IPD Sharing Access Criteria: Summary study report will be shared by Principal Investigator upon request if not published in public literature
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No