An interventional study of In this study, a probiotic lozenge formulation containing S. salivarius K12, M18 and prebiotic will be evaluated for its potential to improve bad breath and Placebo in Halitosis, sponsored by John Hale. Not yet recruiting at 1 site in New Zealand. Open to participants aged 18 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-04.
Sponsored by John Hale · Not applicable, Interventional, and Basic science
The aim of this study is to evaluate efficacy of a probiotic lozenge containing BLIS M18, BLIS K12 and a prebiotic in healthy adults.
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.
93 studies on the registry are indexed under Halitosis; 17 are open to participants now.
This study's planned enrollment of 40 is below the median of 45 across 79 interventional studies indexed under Halitosis.
Browse Halitosis studies →John Hale is the lead sponsor of 4 studies on the registry; 1 is open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
Oral lozenges
Other: Placebo
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.
Probiotic free placebo lozenge
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
Time frame: 13 days
Plan to share: Yes — Data and information included in the Protocol and Clinical Study Report will be shared to other researchers and/or in publications in due course.
Supporting information: Study protocol, Clinical study report
Time frame: Study report 3 months after the completion of the study
Access criteria: Summary study report will be shared by Principal Investigator upon request if not published in public literature
Start is estimated for Mar 2026; primary completion for Jun 2026, 3 months later.
Of 43 interventional studies with no phase under Halitosis, half reached primary completion within 10 months of starting (the median), counting those still running; a quarter within 3 and three quarters within 18. This study's planned 3 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Feb 2026. You cannot join it, but the record below documents what was studied.
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