If protein and caffeine are the basics of fueling for performance, nitric oxide boosters are the next level. Yeah, nitric oxide sounds like something that’d make your car fast and furious, but this naturally-produced chemical can actually help you get your butt in gear, too.

How Nitric Oxide Works

Nitric oxide, or N.O., stimulates hormones in your body involved in your blood circulation and blood vessel relaxation, explains Brian Tanzer, M.S., nutritionist and manager of scientific affairs for The Vitamin Shoppe. Our body produces N.O. when a lot of blood is trying to get through our blood vessels. The chemical then dilates those blood vessels (called ‘vasodilation’) to make it easier for the blood to get through, according to the University of Michigan. Because our blood transports oxygen and nutrients throughout the body, better blood flow is good news for all of your system’s major players, like your heart and brain.

And when you’re exercising, better circulation means more blood—plus oxygen, protein, and nutrients—gets to your working muscles. This, in turn, helps your cells churn out more energy.

Here’s how: These tiny powerhouses in your cells, called mitochondria, create energy called ATP that your body uses to chug through whatever it’s doing. Oxygen is one of the ‘ingredients’ in ATP, so by boosting your circulation—and oxygen flow to your muscles—N.O. helps fire up your energy production, according to a review published in Sports Medicine.

“So whether you’re strength-training or doing cardio like running or swimming, that extra flow of blood and oxygen into the muscles can boost performance,” Tanzer says. And, in case you were wondering—yes, dilated blood vessels may also mean getting that super ‘vascular’ look where your veins really pop.

Plus, in theory, the extra blood and nutrients flowing to your muscles can also promote recovery after you finish lifting or pounding pavement, according to the University of Michigan.

Boosting Your N.O.

So yeah, we’ll take one nitric oxide power-up, please. Our bodies produce a bit of nitric oxide on their own to help support our working muscles when we exercise, and the more we train, the better our bodies become at making N.O., according to a review published in the Strength and Conditioning Journal. But there are other ways we can boost our production even more, says Tanzer.

Amino acids (the molecules that build protein) contain the nitrogen our bodies need to produce nitric oxide. Protein is your only food source of nitrogen, explains Tanzer, but you can also get that nitrogen from an amino acid supplement

Related: Could Creatine Take Your Fitness To The Next Level?

Two aminos in particular, citrulline and arginine, are best known for their nitric oxide-producing abilities. Arginine was the original all-star for boosting nitric oxide, though citrulline now seems to be the more effective of the two, Tanzer says.

One study published in the Journal of the International Society of Sports Nutrition, for example, found that cyclists who supplemented with citrulline regularly performed better on a time trial test and reported feeling less fatigued afterward as compared to those who took a placebo.

This is why you’ll see citrulline in tons of pre-workout formulas—and even as a supplement on its own. Tanzer recommends about six grams before you exercise, though you’ll still benefit from the smaller amounts found in pre-workouts.

Another way to pump up that nitric oxide production: dietary nitrates. These compounds can also be used to create N.O. and are found in a bunch of fruits and veggies (often because of the fertilizer used). Beets, in particular, are high in nitrates and quite trendy as a performance booster.