When you hear about body builders using NO – or nitric oxide – to enhance their gains at the gym, you can be forgiven for mistaking nitric oxide for the dental anesthetic nitrous oxide, sometimes called “laughing gas.” Although nitrous (N20) has been around since 1844, the importance of NO as a biological signal molecule was only discovered recently.

What does NO do?

NO is responsible for “the pump,” that way your muscles get full of blood and tight after a really great workout.It does this by signaling the smooth muscle cells of the small blood vessels to relax and open up, allowing more blood to pass through.


Here are a few benefits athletes get from a nitric oxide supplement. For one thing, NO improves post-workout recovery. After a serious workout, you probably find that you are tired the next day or two. That’s when your body rebuilds and when your gains in muscle mass happen. NO improves blood flow to the overworked muscle, delivering more oxygen and nutrients and thereby speeding up the recovery process. Over time, you can get in more workouts and build muscle faster.

NO supplementation will also lower your level of fatigue during endurance or high repetition sessions. If fatigue limits how much you can do, NO may help. You should see both an increase in the number of reps and in the number of sets you can put into a resistance workout. Your ability to handle higher levels of resistance for longer times on the aerobic machines should also measurably improve.

High repetition exercise will also generate a buildup of lactic acid, causing muscle soreness afterward along with fatigue. Lactic acid has to be converted in the liver to be recycled as acetyl CoA and to do that, you need to wash it out of the overworked tissue. Improving microcirculation with NO can help with that.


NO is not just a supplement for strength training. It is also beneficial to endurance athletes – marathoners and triathletes. This makes sense, since the benefit of NO is to deliver more oxygen to the tissues.

Related to that, people who must perform at altitude, like mountain climbers, may find NO beneficial as well. Indeed, endurance athletes sometimes train at altitude in order to stress their oxygen carrying capacity and improve their aerobic fitness.


An often-overlooked aspect of fitness is temperature regulation. We are warm-blooded animals and must keep our core temperatures within a narrow range. When we exercise, we generate more heat and must get rid of it before it raises our temperatures beyond a range compatible with life. We do this by dissipating energy through the skin. The blood carries the heat to the periphery and, through NO signaling, the small blood vessels open up, allowing this heat transfer to take place.

More efficient thermal regulation means better results, especially in seasons and climates where heat is a problem.

Weight loss

NO also appears to have some application to reducing body fat. Muscles run on fatty acids most of the time, but when they spring into action, glucose is the preferred source of immediate energy. You can use up all available ATP (the energy molecule inside the cells) in a few seconds of sprinting. After that, it has to be replaced by breaking down glucose, which it gets from the blood and ultimately from supplies of glycogen stored in the liver. After about 40 minutes of running, that’s all used up and the body converts to reliance on fat burning. Studies have shown that you can speed up the process of burning off the glucose and getting down to burning fat faster with NO supplementation.