Some people claim fluoride destroys the beneficial bacteria your body needs to produce nitric oxide, while others say there’s no evidence to support the concern. So, what’s the truth?
Because one important pathway for producing nitric oxide depends on beneficial bacteria in the mouth, some people have questioned whether fluoride toothpaste, fluoride mouthwash, or fluoridated drinking water could interfere with this process.
This article examines what the research says about fluoride, the oral microbiome, and nitric oxide production
Does Fluoride Destroy Nitric Oxide?
Probably not with routine use.
Current evidence does not show that fluoride toothpaste, fluoride mouthwash, or fluoridated drinking water impair nitric oxide production in healthy people.
The concern stems from two different ideas:
- First, an animal study found that mice exposed to very high concentrations of fluoride had lower blood nitric oxide levels, increased oxidative stress, and reduced antioxidant activity. However, the fluoride concentrations used were far higher than those associated with everyday exposure, so the findings cannot be directly applied to routine fluoride use in humans.
- Second, some people worry that fluoride might reduce the beneficial oral bacteria involved in converting dietary nitrate into nitrite, an important step in nitric oxide production.
Most human research linking reduced nitric oxide production to changes in the oral microbiome has focused on strong antiseptic mouthwashes rather than fluoride products.
Why Nitric Oxide Is Important
Nitric oxide (NO) is a gas that your body naturally produces. Although it exists for only a few seconds before breaking down, it has a powerful effect on nearly every organ system.
One of its primary jobs is helping blood vessels relax and widen. This process, known as vasodilation, improves blood flow throughout the body.
Healthy nitric oxide levels help support:
- Healthy blood pressure
- Efficient blood circulation
- Delivery of oxygen and nutrients to tissues
- Heart and blood vessel function
- Exercise performance and endurance
- Healthy erectile function
- Brain function
- Immune responses
As we age, the body’s ability to produce nitric oxide naturally declines. Conditions such as diabetes, obesity, smoking, high blood pressure, and chronic inflammation can reduce nitric oxide even further.
How the Oral Microbiome Produces Nitric Oxide
Many people assume nitric oxide is made only inside blood vessels. While that’s true, there is another equally important pathway that depends on the bacteria living in your mouth.
Here’s how it works:
Step 1: Eat nitrate-rich vegetables
Foods naturally high in nitrates include:
- Beets
- Arugula
- Spinach
- Lettuce
- Celery
- Swiss chard
Step 2: Oral bacteria convert nitrate into nitrite
After eating these foods, nitrate enters your saliva.
Beneficial bacteria living mainly on the back of the tongue convert nitrate into nitrite.
Step 3: Nitrite becomes nitric oxide
When swallowed, nitrite is converted into nitric oxide in the stomach and bloodstream, especially in areas where oxygen levels are low.
Without these beneficial oral bacteria, this nitrate-nitrite-nitric oxide pathway becomes much less efficient.
This explains why researchers have become interested in anything that could disrupt the oral microbiome.
Does Fluoride Affect Oral Bacteria?
This question has generated considerable debate because fluoride can affect oral bacteria, but not all bacteria play the same role.
A 2022 study found that brushing with a 1,450 ppm fluoride toothpaste for three months changed the oral microbiome without reducing its overall diversity. This suggests that routine fluoride use does not broadly disrupt oral bacterial communities.
Some oral bacteria, particularly Neisseria and Rothia, help convert dietary nitrate into nitrite, an important step in nitric oxide production. A 2024 review found that dietary nitrate increased these beneficial bacteria while reducing bacteria associated with cavities and gum disease.
However, there is currently little direct evidence that routine fluoride use affects the nitrate-reducing bacteria involved in nitric oxide production.
Fluoride vs. Antibacterial Mouthwash: What’s the Difference?
People often confuse fluoride mouthwash with antiseptic mouthwash, but they work very differently.
Fluoride Mouthwash | Antibacterial Mouthwash |
|---|---|
Strengthens enamel | Kills bacteria |
Helps prevent cavities | Reduces bacterial growth throughout the mouth |
Not intended to sterilize the mouth | Broad-spectrum antimicrobial action |
Little evidence it significantly reduces nitrate-reducing bacteria | Can reduce nitrate-reducing bacteria and temporarily decrease nitric oxide production |
A human study found that a chlorhexidine-containing antiseptic mouthwash reduced the oral bacteria responsible for converting nitrate into nitrite. As a result, salivary and plasma nitrite levels decreased, and participants experienced a small increase in blood pressure.
However, a 2025 review found that any increase in blood pressure from chlorhexidine mouthwash is generally very small or clinically insignificant.
Most of the evidence linking these effects comes from antiseptic mouthwashes rather than routine fluoride mouthwash use.
Should You Stop Using Fluoride Toothpaste or Mouthwash?
For most people, no.
The benefits of fluoride for preventing tooth decay are well established, while evidence linking normal fluoride use to impaired nitric oxide production remains lacking.
If your goal is to support nitric oxide production, you’re likely to see much greater benefits from focusing on proven lifestyle habits than eliminating fluoride.
That said, you may want to be mindful of frequent use of strong antibacterial mouthwashes, especially if they contain ingredients known to broadly suppress oral bacteria. These products may temporarily reduce the nitrate-to-nitrite conversion that contributes to nitric oxide production.
If you have concerns about fluoride exposure due to naturally high-fluoride well water, occupational exposure, or fluoride supplements, it’s worth discussing them with your healthcare provider.
Ways to Support Healthy Nitric Oxide Production
Rather than worrying about fluoride, focus on habits that are known to support nitric oxide:
Eat more nitrate-rich vegetables
Leafy greens and beets provide the raw materials needed for nitric oxide production.
Exercise regularly
Aerobic and resistance exercise stimulate the enzyme responsible for producing nitric oxide inside blood vessels.
Don’t overuse antibacterial mouthwash
Occasional use is unlikely to cause lasting problems, but frequent use of strong antiseptic mouthwashes may reduce beneficial nitrate-reducing bacteria.
Avoid smoking
Smoking damages blood vessels and significantly lowers nitric oxide availability.
Get enough sleep
Poor sleep is associated with impaired endothelial function and reduced nitric oxide production.
Eat antioxidant-rich foods
Fruits, vegetables, nuts, seeds, and legumes provide antioxidants that help protect nitric oxide from being broken down by free radicals.
Manage cardiovascular risk factors
Keeping blood pressure, cholesterol, blood sugar, and body weight within healthy ranges supports the cells that produce nitric oxide.
The Bottom Line
Current human evidence does not support the claim that routine fluoride use destroys nitric oxide.
Most concerns come from high-dose laboratory and animal studies, while human research has primarily linked reduced nitric oxide production to strong antiseptic mouthwashes rather than fluoride products.
For most people, using fluoride products as directed while maintaining a healthy diet and lifestyle remains an evidence-based approach to supporting both oral health and nitric oxide production.