Do Nitric Oxide Supplements Actually Work?

Experts also weigh in on their safety.By Erica Sweeney, Lisa MulcahyPublished: Jun 01, 2026 5:33 PM EDTSave ArticleShare Article

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Key Points

• Nitric oxide supplements work by increasing vasodilation, delivering more oxygen and nutrients to muscles while exercising. However, experts say the research supporting claims of improved fitness performance and endurance are mixed.
• Except for potential vomiting and diarrhea, nitric oxide supplements are “generally harmless.” While there is no official dosage recommendation, experts say 6 to 13 grams appears to be most tolerable.
• Food sources are always preferred to supplements since they come with additional ingredients such as antioxidants and vitamins. Some examples are beets and leafy greens since they are high in nitrates.

IF BOOSTING YOUR endurance at the gym (and in the bedroom) are on the top of your list of health goals, you might have heard about nitric oxide supplements. Along with the above, the popular supplement is linked to a number of other health benefits. But does it actually work?

First things first: nitric oxide isn’t the same as nitrous oxide, also known as laughing gas, or the stuff that gets you a little high at the dentist. So, what exactly is nitric oxide?

What Is Nitric Oxide?

“NITRIC OXIDE IS a gas and free radical that’s recognized to play a role in several physiological systems,” says Alex Rothstein, MS, instructor in the exercise science program at the New York Institute of Technology. It’s synthesized from L-arginine, an essential amino acid.

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Nitric oxide acts as a vasodilator, which means it helps open blood vessels. As a result, many people take the precursor L-arginine for issues like erectile dysfunction and to improve heart health.

Nitric oxide’s role in vasodilation is also important for regulating blood pressure, says William Workman, MD, orthopedic surgeon and sports medicine expert at DISC Sports & Spine Center in Walnut Creek, California.

Many small blood vessels and capillaries sit dormant until you get your heart rate up during exercise, and nitric oxide enables blood to flow to these areas to allow your muscles to work, hence its reputation as a substance that can help your fitness performance.