The Effects of Nitrate-Rich Mouthwash on Vascular Tone (NITRATONE)

The Short-Term Effects of Nitrate-Rich Mouthwash on Oral Bacterial Nitrite Production, Blood Pressure, and Nitrate and Nitrite Concentrations in Plasma and Saliva of Healthy Adults

High blood pressure (hypertension) is a major risk factor for cardiovascular disease. One important contributing factor to high blood pressure is reduced availability of nitric oxide (NO). Therefore, NO is an important molecule in maintaining healthy blood vessel function.

Dietary nitrate, found in leafy greens, can serve as an alternative source of nitric oxide in the body. After ingestion, nitrate is converted to nitrite by bacteria residing in the oral cavity. Nitrite can subsequently be converted to NO when swallowed. Therefore, this nitrate-nitrite-nitric oxide pathway is dependent on oral bacteria.

This study aims to assess whether rinsing the mouth with a nitrate-rich mouth rinse influences blood pressure in healthy adults. Also, concentrations of nitrate and nitrite in plasma and saliva will be measured following the nitrate-mouth rinse exposure.

Study Overview

• Status: Not yet recruiting
• Conditions: Blood Pressure Regulation
• Intervention / Treatment: Dietary supplement: Nitrate-rich mouth rinse; Dietary supplement: Placebo; Dietary supplement: Placebo; Dietary supplement: Nitrate-rich drink

Detailed Description

This study investigates the potential acute blood pressure lowering effects of a simple nitrate-rich mouth rinse and drink, while also monitoring their effects on oral nitrite production capacity (NPC), plasma and salivary nitrate and nitrite levels, oral pH levels and the oral microbiology.

The study is a short-term, double-blind, randomized, placebo-controlled, crossover trial.

Participants will receive interventions and donate samples at four separate sessions. At session (i), baseline measurements are taken prior to intervention, and samples are subsequently taken (as described under outcome measures). At session (i) and (ii), the participants will rinse the oral cavity with a nitrate-rich fluid (or placebo). Similarly for sessions (iii) and (iv), the participants will drink the same fluid (or placebo). When donating samples, the participants will be in fasting condition. In total there will be four sessions per participant with wash-out periods in-between.

To elucidate the short-term effects of the above-described interventions, sampling will be performed in the clinic at multiple time points during the first 2 hours after each intervention, as well as at 24 hours. Participants will also monitor their blood pressure at home at four different time points for all four interventions. No sampling or measurements will be performed during night-time.

For both the intervention and the placebo, potassium (K) salts are used (KNO3 and KCl). For chairside measurement of NPC in oral samples, the rapid Griess assay (RGA) will be used. Blood pressure will be measured at the study facilities as clinic blood pressure and orthostatic blood pressure (CBP and OBP, respectively) using a clinically validated blood pressure monitor. The same device will be used by the participants for home blood pressure measurements (HBP). Saliva pH will be measured using pH-sticks or a pH-meter. Plasma and saliva nitrate- and nitrite levels are analyzed using commercial laboratory kits. Salivary secretion rate (SCR) is recorded during saliva donation, and measured as volume per unit time. Microbiological effects will be analyzed with appropriate methods in the laboratory.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Simeon KB Mavropoulos, DDS, MSc; Phone Number: +46766185930; Email: simeon.mavropoulos@gu.se
• Study Contact Backup: Name: Amina Basic, PhD, DDS; Phone Number: +46766185930; Email: amina.basic@gu.se

Study Locations

• Sweden
  • Västra Götaland County
    • Gothenburg, Västra Götaland County, Sweden, 41390
      • Odontologen, University of Gothenburg
      • Contact: Amina Basic, DDS, PhD; Phone Number: +46766185930; Email: amina.basic@gu.se

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• ≥18 years of age; and
• clinic blood pressure <140/<90 mmHg.

Exclusion criteria:

• hypertension;
• systemic medication (other than the oral contraceptive pill);
• antibiotic treatment within the last 3 months;
• active smoking status and BMI > 30;
• prior gastric by-pass surgery;
• self-reported use of antiseptic mouthwash or toothpaste;
• self-reported use of tongue scrapes; and
• active periodontal disease or caries that needs treatment.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Test mouth rinse; In this arm participants will receive nitrate rich-mouth rinse	Dietary supplement: Nitrate-rich mouth rinse; The oral cavity is rinsed with nitrate from mouth rinse, rather than ingested.; Other Names: Nitrate mouth rinse
Placebo Comparator: Placebo mouth rinse; In this arm participants will receive placebo mouth rinse	Dietary supplement: Placebo; This mouth rinse is devoid of nitrates; Dietary supplement: Placebo; This drink is devoid of nitrates
Active Comparator: Test drink; In this arm participants will receive nitrate-rich drink	Dietary supplement: Nitrate-rich drink; Nitrate is ingested, rather than rinsed and spit out; Other Names: Nitrate drink
Placebo Comparator: Placebo drink; In this arm participants will receive placebo drink	Dietary supplement: Placebo; This mouth rinse is devoid of nitrates; Dietary supplement: Placebo; This drink is devoid of nitrates

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure before and at regular intervals within the 24 hours after nitrate exposure.	Blood pressure will be measured before and with regular intervals after nitrate exposure. The measurements will be registered as systolic and diastolic measurements from clinic blood pressure and home blood pressure.	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.
Oral nitrite production before and at regular intervals within the 24 hours after nitrate exposure.	The nitrite production is measured using the rapid Griess assay (RGA) - a chairside semi-quantitative nitrite concentration estimation tool for use in several different oral samples. The RGA provides nitrite estimation on a grading scale of 0-5 with nitrite concentrations intervals.	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma and salivary nitrate and nitrite levels before and after nitrate exposure.	Blood samples are drawn from venous blood before and 1 hour after nitrate exposure, and plasma is separated. Saliva nitrate/nitrite is extracted from saliva samples donated before and 1 hour after nitrate exposure. Both are analyzed using commercial laboratory kits.	Baseline (prior to nitrate exposure) and 1 hour after nitrate exposure.
Salivary pH levels at regular intervals.	Salivary pH will be measured using a pH-stick at regular intervals before and after nitrate exposure.	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.
Orthostatic blood pressure before and at regular intervals within the 24 hours after nitrate exposure.	Orthostatic blood pressure will be measured at regular intervals before and after nitrate exposure and reported as systolic and diastolic blood pressure values in mmHg.	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.
Salivary secretion rate before and after nitrate exposure.	Salivary secretion rate will be registered as volume per unit time when donating saliva before and after nitrate exposure with regular intervals.	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.
Relative abundance in cultivable oral microbial composition after nitrate exposure	Microbial samples from multiple oral sites will be collected before and after nitrate exposure. Oral microbial composition will be analyzed and reported as the relative abundance (%).	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.
Absolute abundance in cultivable oral microbial composition after nitrate exposure	Microbial samples from multiple oral sites will be collected before and after nitrate exposure. Cultivable oral microbial composition will be analyzed and reported as absolute abundance and expressed as colony-forming units per milliliter (CFU/mL).	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.
PCR detection of specific oral bacterial after nitrate exposure	Microbial samples from multiple oral sites will be collected before and after nitrate exposure. Quantitative PCR analysis will be performed for selected oral bacterial species and reported as bacterial counts or copy numbers.	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.
Oral microbial metabolite concentrations after nitrate exposure	Microbial samples from multiple oral sites will be collected before and after nitrate exposure. Oral microbial metabolites will be analyzed and reported as metabolite concentration values.	Baseline (prior to nitrate exposure) and during the 24 hours after nitrate exposure.

Collaborators and Investigators

• Sponsor: Göteborg University
• Investigators: Principal Investigator: Amina Basic, PhD, DDS, Göteborg University

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: December 29, 2025
• First Submitted That Met QC Criteria: May 19, 2026
• First Posted (Actual): May 22, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Mouth rinse; Plasma nitrate; Blood pressure regulation; Nitrate supplement; Nitrate reduction; Plasma nitrite; Saliva nitrate; Saliva nitrite
• Other Study ID Numbers: 2025-02639-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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