Is it safe to take nitric oxide every day? A comprehensive guide to risks and benefits

December 26, 2025 •

3 min read

Nitric oxide is a crucial signaling molecule in the human body, helping to relax blood vessels and improve blood flow. While supplements containing precursors like L-arginine, L-citrulline, and nitrates have grown popular for enhancing athletic performance and supporting heart health, a common question remains: is it safe to take nitric oxide every day?

Quick Summary

This guide evaluates the safety of daily nitric oxide supplementation by detailing potential side effects, identifying high-risk individuals, and outlining important medication interactions, highlighting the need for professional medical advice.

Key Points

Generally Safe for Healthy Adults: Daily nitric oxide supplementation is likely safe for most healthy individuals when following recommended dosages.
Not for Everyone: Individuals with heart conditions, low blood pressure, liver or kidney disease should not take these supplements without strict medical supervision.
Medication Interactions: There is a risk of dangerous interactions with blood pressure, erectile dysfunction, and heart medications.
Consider Cycling: To prevent the body from building a tolerance, a regimen of cycling the supplement (e.g., 4-8 weeks on, 2-4 weeks off) may be beneficial.
Natural Alternatives are Safer: Boosting nitric oxide through a diet rich in nitrates (beets, leafy greens) and regular exercise is a safer and reliable long-term strategy.
L-Citrulline is More Bioavailable: L-citrulline is often preferred over L-arginine due to its superior absorption and longer-lasting effects.
Consult a Doctor: Always talk to a healthcare provider before starting any new supplement, especially if you have pre-existing health issues or take medication.

What is Nitric Oxide and How Do Supplements Work?

Nitric oxide (NO) is a simple but vital gas produced naturally by the body. Its primary function is vasodilation, the widening of blood vessels, which improves circulation and oxygen delivery to muscles and organs. Supplements do not contain pure nitric oxide. Instead, they contain precursors, substances the body converts into NO. The most common precursors are the amino acids L-arginine and L-citrulline, and nitrates derived from foods like beetroot. Daily supplementation is intended to maintain elevated levels of these precursors to support nitric oxide production.

L-Arginine vs. L-Citrulline

When it comes to supplementing with amino acid precursors, L-arginine and L-citrulline are the two main contenders. While both serve the same ultimate purpose, they differ in how efficiently they raise plasma arginine and, subsequently, nitric oxide levels.


Feature	L-Arginine	L-Citrulline
Mechanism	Converted directly to NO via the enzyme NOS.	Converted to L-arginine in the kidneys before being used for NO synthesis.
Absorption	Lower bioavailability due to metabolism in the intestines and liver (first-pass metabolism).	Superior bioavailability; it bypasses first-pass metabolism, leading to more sustained and higher plasma L-arginine levels.
Daily Dosage	Typically requires lower doses (e.g., 2–6g).	Typically requires higher doses (e.g., 3–8g).
Side Effects	More prone to causing digestive issues like diarrhea at higher doses (>9g).	Generally better tolerated with fewer gastrointestinal complaints.
Effect Profile	Provides a quicker, but shorter-lasting, boost.	Creates a more sustained release and longer-lasting effect.

Potential Benefits of Daily Nitric Oxide Supplementation

For healthy individuals, especially recreational athletes, daily intake may offer several benefits, although the evidence is sometimes mixed, especially for elite athletes. Daily supplementation may offer benefits like enhanced exercise performance, cardiovascular support by helping to lower blood pressure, reduced muscle soreness, and support for erectile function.

Side Effects and Risks of Daily Supplementation

While generally considered safe for most healthy adults, daily use is not without potential downsides. Side effects are often mild but can be more serious for certain individuals.

Common Mild Side Effects

Common mild side effects can include gastrointestinal issues such as nausea, diarrhea, and stomach pain, particularly with high doses of L-arginine. Headaches and dizziness may also occur due to vasodilation, especially in those with low blood pressure. Beetroot-based supplements can cause harmless beeturia.

Significant Health Risks and Contraindications

Daily nitric oxide supplementation can pose serious risks for people with certain health conditions or those taking specific medications. Individuals with low blood pressure risk a dangerous drop. Those with heart conditions, especially post-heart attack patients, may face increased risks, as seen in studies on L-arginine. Dangerous interactions can occur with medications for blood pressure, erectile dysfunction, and chest pain. Risks are also associated with liver and kidney disease, potentially worsening function. L-arginine may also trigger herpes outbreaks.

The Role of Cycling and Natural Alternatives

Some experts recommend cycling intake to avoid tolerance and long-term side effects, suggesting cycles like 4–8 weeks on followed by 2–4 weeks off. Natural alternatives like diet and exercise are highly effective and safer. Regular physical activity stimulates the enzyme that produces NO, while nitrate-rich foods also boost levels without high-dose supplements.

Foods that naturally boost nitric oxide:

Leafy green vegetables (spinach, arugula, kale)
Beets and beetroot juice
Celery
Watermelon
Garlic
Pomegranate

Conclusion: So, Is It Safe to Take Nitric Oxide Every Day?

For a healthy individual without underlying conditions, daily nitric oxide supplementation at recommended doses is likely safe, though long-term data is limited. However, it's not universally safe and carries significant risks for those with pre-existing heart, liver, or kidney problems, or those on certain medications. Benefits may be marginal for some, particularly highly-trained athletes. Consulting a doctor is essential before starting daily supplements to assess individual risks, interactions, and contraindications. Prioritizing nitrate-rich foods and consistent exercise is generally a safer and more beneficial long-term approach to increasing nitric oxide levels.

Authoritative Source

For information on the general safety and efficacy of dietary supplements, consult resources from the National Institutes of Health. National Institutes of Health Office of Dietary Supplements

Frequently Asked Questions

The most common side effects are mild and include gastrointestinal issues like nausea, diarrhea, and stomach pain. Some people may also experience headaches or dizziness, especially if they have low blood pressure.

Yes, it can be dangerous. Individuals with certain heart conditions, particularly those who have had a recent heart attack, face a higher risk of adverse cardiovascular events with some nitric oxide precursors like L-arginine.

For most individuals, obtaining nitric oxide through nitrate-rich foods like beets and leafy greens is a safer and more reliable option, as it avoids the potential side effects and risks associated with concentrated supplements.

Yes, some experts recommend cycling nitric oxide supplements to prevent the body from building a tolerance. A common cycling regimen is taking the supplement for 4–8 weeks, followed by a 2–4 week break.

People with low blood pressure, heart disease, recent heart attacks, liver cirrhosis, kidney disease, or herpes should avoid daily nitric oxide supplementation without strict medical approval.

L-citrulline is generally considered more effective for daily use due to its superior bioavailability. It is converted to L-arginine in the body, leading to more sustained and higher nitric oxide levels compared to L-arginine, which is often metabolized too quickly.

Most healthy women can safely take nitric oxide supplements, but there is limited research on supplementation during pregnancy or breastfeeding. It is recommended that pregnant or nursing women avoid them unless specifically advised by a doctor.