NO, the Facts: An Insider’s Guide to Nitric Oxide

NO, the Facts: An Insider’s Guide to Nitric Oxide

Arnold Schwarzenegger once said that getting pumped at the gym feels as good as an orgasm. While we can’t confirm or dispute that claim (to each their own, Arnie), we can say this: A good pump—that swollen feeling you get when you lift weights as your muscles engorge with blood—has benefits beyond vanity. Indeed, it can help you build more muscle by increasing protein synthesis and decreasing muscle breakdown, according to a recent review in the Strength and Conditioning Journal.

That’s just one more reason to give nitric oxide boosters like arginine, citruline, and even beets and leafy greens a try—by relaxing blood vessels, they can help facilitate the pump and all of its associated benefits. “Nitric oxide boosting is one of the only reliable ergogenic [performance enhancing] aids aside from creatine,” says Kamal Patel, MPH, director of, an independent resource for supplement information. “Plus there are clear cardiovascular perks [such as improved blood flow].” Here’s what you need to know to optimize your results.


What is nitric oxide?

Often referred to by its molecular shorthand, NO, nitric oxide is a gas composed of nitrogen and oxygen that’s primarily used to deliver messages between cells. But it also functions as a “vasodilator,” helping blood vessels open up (i.e., dilate) by relaxing their walls. Why is that important? Because relaxed vessels can deliver more oxygen and nutrients—including glucose and amino acids—to working muscles. And as the study above points out, as muscles swell with blood, the pressure within them increases, forcing cells to adapt by reinforcing their walls. The combined effect: Bigger, thicker, stronger muscles.

Increasing nitric oxide production can also raise your body’s production of growth hormone, according to a study in the journal Endocrine. Growth hormone (GH) is a key player in your body’s ability to not only strengthen and build muscle, but also burn fat.


What’s the best way to boost nitric oxide levels?

The most potent method is to eat more beets and leafy greens like kale, Swiss chard, arugula, and spinach, which are rich in nitrates and nitrites—compounds known to stimulate the production of nitric oxide. In a recent British study, recreational athletes who consumed beetroot juice before a tough workout boosted performance by more than 4 percent compared to those who did not. “The mechanism for nitric oxide production from veggies is different than that for straight amino acids like arginine or citruline,” says Patel. “And eating dietary sources pre-workout can increase nitric oxide production to higher levels.”

A salad with any (or all) of the above greens (and reds) will do. So will a similarly composed smoothie. But here’s the thing: You need to allow at least 60 (and preferably more) minutes between your salad or smoothie and your workout in order for your body to digest the food and ramp up nitric oxide production. “And if you decide to go the dietary route, avoid using antiseptic mouthwash right after you eat,” says Patel. “It kills oral bacteria, which are needed for the conversion.”

Which brings us back to supplements like citruline and arginine: Although not as potent as food-based NO boosters, they offer a more immediate effect, making them more convenient. Whatever supplement you choose, take it 15 to 30 minutes pre-workout. “Make sure your stomach is empty,” says Patel. “You want the effects kick in at the right time [read: during your workout], and eating food will blunt or prevent them.”