Muscle for life

Do Nitric Oxide Supplements Work? An Evidence-Based Review

Do Nitric Oxide Supplements Work? An Evidence-Based Review

Nitric oxide supplements are sold like they’re as good as steroids but what does the research say? Worthwhile or worthless? Read on to find out.


Do you want rock-freaking-hard biceps and boners!?

How about shirt-ripping workout pumps that make the ladies squirm and fellas burn!?!

And what about massive, heard-turning muscles that pulsate with veins so thick you could use them for surgical tubing!?!?!?!

Well, today’s your lucky day, Broseidon. A bunch of super-powerful scientists have descended from the heavens to deliver the secret to swole to us musclebound idiots.

It’s called nitric mothafuckinoxide and it’s so damn good at hacking your biology and force-feeding your muscles nutrients and hormones and shit that it was given a Nobel Prize!

That was basically copy and pasted from a sales page for a popular nitric oxide supplement.

Okay…I…touched it up a little. But not much.

Shenanigans aside, there’s no denying that nitric oxide supplements are extremely popular. Guys and gals spend tens of millions of dollars on them every year in hopes of building muscle and strength faster.

But do they work? Or are they a waste of money like most other bodybuilding supplements?

Let’s find out. Bro.

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What Are Nitric Oxide Supplements?

The first thing you need to know about these supplements is they don’t contain nitric oxide, which is a gas.

Instead, most contain as their primary ingredients one or more forms of the amino acid arginine (with arginine alpha-ketoglutarate being the most popular).

This amino acid is supposed to boost nitric oxide levels in the blood, which in turn is supposed to increase your muscle growth, strength, and performance.

What does the research say, though?

The (Apparent) Benefits of Nitric Oxide Supplements

Most nitric oxide supplements are sold first and foremost as potent muscle builders.

To that end, supplement marketers often cite research showing that arginine supplementation can raise nitric oxide levels in the body, which widens blood vessels and improves blood flow.

This blood flow mechanism has been shown to improve exercise performance in patients with cardiovascular disease and improve endothelial health (the endothelium is the lining of the blood vessels).

Increasing blood flow to the muscles also increases nutrient delivery, which has been shown to elevate protein synthesis rates. This is why arginine and nitric oxide supplements in general are often marketed like they’re natural steroids.

Another mechanism of arginine touted as a clincher is its ability to raise growth hormone production in response to exercise. This is music to the average consumer’s ears, who is indoctrinated to believe that more growth hormone of any kind and amount is going to help them build more muscle.

This all sounds pretty sexy, but look a bit closer and you start noticing flies in the soup.

Let’s tackle the growth hormone claims first because they’re 100% bogus.

Yes, supplements that increase nitric oxide levels like arginine and citrulline can increase growth hormone levels when you exercise, but no, this isn’t going to help you build more muscle.

The long story short is this: growth hormone has potent anticatabolic effects but doesn’t stimulate the growth of skeletal muscle and doesn’t increase strength. And I’m referring to dramatically spiking hormone levels by directly injecting GH, not taking a supplement that weakly augments natural production for an hour or less.

And just to drive a final nail in the growth hormone coffin, let’s take a look at an interesting study conducted by scientists at McMaster University with young, resistance trained men.

The subjects lifted 5 times per week for 12 weeks and followed a standard dietary protocol (high-protein intake, post-workout nutrition, etc.).

The primary finding of the study was that the exercise-induced spikes in anabolic hormones like testosterone, growth hormone, and IGF-1, which all remained within physiological normal ranges, had no effect on overall muscle growth and strength gains.

That is, all subjects made gains in muscle, but the variations in the size of the hormone spikes among them had no bearing on the results.

The key takeaway here is not that you should take steroids, but that things you can do to naturally raise your anabolic hormone levels are unlikely to affect your muscle growth.

And in case you’re wondering why growth hormone has become so popular in the world of bodybuilding if it doesn’t help you build muscle, it seems to greatly enhance muscle growth when combined with regular (and dangerous) use of insulin and large doses of anabolic steroids.

So, with nitric oxide’s growth hormone mechanisms brought into line, let’s move on.

The big problem with arginine as a nitric oxide booster and ergogenic aid is its unreliability. That is, it works for some people but not others.

This explains why nitric oxide supplements are very hit-and-miss–some swear by the bigger pumps and better workouts and others notice absolutely nothing.

The best that can be said about arginine is if you take enough (6 to 10 grams), it may or may not help you get more out of your workouts.

Not very exciting, I know. And that’s why I don’t recommend arginine supplementation for workout purposes.

Instead, I recommend and personally use the amino acid citrulline instead.

Citrulline is turned into arginine in the kidneys and results in larger and longer elevations of plasma arginine levels than supplementation with L-arginine itself. It also elevates plasma levels of another amino acid, ornithine, which reduces exercise-induced fatigue.

This is why research shows citrulline can reliably improve exercise performance and reduce fatigue and muscle soreness.

If you want to try citrulline for yourself, check out my 100% natural pre-workout supplement PULSE. It contains 8 grams of citrulline malate in every serving along with clinically effective dosages of 5 other ingredients proven to increase physical and mental performance.

The Bottom Line on Nitric Oxide Supplements

Research clearly shows that raising plasma nitric oxide levels can improve workout performance. Supplements that accomplish this are worthwhile additions to your regimen if you’re looking to maximize performance.

That said, the benefits of nitric oxide supplements are often oversold. They aren’t going to skyrocket strength or help you pack on mass like steroids.

A more realistic view is if a nitric oxide supplement can help you train harder over many workouts, and if you actually take advantage of this by pushing yourself in your training, you can make more progress than if you hadn’t taken it.

If you want to see what a nitric oxide supplement can do for you, go with citrulline instead of arginine. Take a clinically effective dosage of 6 to 8 grams per day and you should improvements in your workouts within a week.


What’s your take on nitric oxide supplements? Have anything else to share? Let me know in the comments below!

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I'm Mike and I'm the creator of Muscle for Life and Legion Athletics, and I believe that EVERYONE can achieve the body of their dreams.

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  • Pingback: Do Nitric Oxide Supplements Work? An Evidence-Based Review | georgeherman205()

  • Greg Groves

    Hey Mike, I’ve taking critulline for about 3 months now (about 7 – 8 g a day), and haven’t noticed anything different at all in my lifts. do you think I should just drop it?

    • Maybe. Are you noticing better pumps while training? Anything at all?

      • Greg Groves

        A little, yes. But I’m just over 4 weeks into a reverse diet, and I always feel better pumps at this point

        • True. Well if you aren’t noticing anything after several months I would cut it and replace with something like beta-alanine or betaine. I’m sure you’re already taking creatine?

  • MsJadensDad .

    I want heard turning muscles–who doesn’t?


    • Gary

      Nice muscles,not huge gross ones

  • I’d really like to try your line of supplements, but the shipping cost to Canada is still pretty high. Isn’t there a cheaper shipping option available?

    • Greg Groves

      I was wondering the same thing (also from Canada)

    • Unfortunately not yet. Shipping out of the country is expensive, even with USPS. But we will be working more on this later in the year. There are solutions but we have to be willing to risk a fair amount of money to see how they go.

  • Zsolt

    It is not clear from your article if I should take citrulline every day or only just before workouts. I’m training 3 times a week, so there is a difference 🙂

    Until now I thought that if I take citrulline before the workout it will improve that workout, but now it seems that I need to take it regularly to have any effect at all.

    Could you please clarify?


    • Noob

      wondering the same thing

    • Good question. Just before working out is fine. You’re not causing anything to accumulate in muscles like with creatine or beta-alanine.

      • Zsolt

        What confused me was that you wrote that you should see improvements within a week. 🙂

        • Sometimes the improvements are subtle but many people notice a significant increase in endurance and muscle pumps.

  • Mark Duddridge

    Lol… Love the intro paragraph, Mike. Better be careful… You’re gonna start getting job offers from supp companies 😉

  • Ollie

    Hey Mike,

    I’m on the last week of my cut at the moment and I was just wondering if it’s ok to do all your cardio sessions each day after each other? I ask because I’ve been doing this (so I have 2-3 days rest before squats) and I know you say you lose a few reps in the last couple weeks of your cut but my squats seem to be a lot harder to hit than my other lifts, I’m just wondering if this is because of the 4 cardio sessions I’m doing a week?



    • Squatting at the end of a cut sucks. No doubt about it. But I don’t quite understand your question. Could you elaborate?

      • Ollie

        Ok so this is what I’m currently doing with cardio and legs:

        Monday: Rest
        Thursday: Rest
        Wednesday: Leg day
        Thursday: HIIT
        Friday: HIIT
        Saturday: HIIT
        Sunday: HIIT

        Basically is it okay for me to do cardio 4 days in a row or should I spread it out more?

        I feel like through working my legs ever day I might be breaking down my muscles at a faster rate then they are able to repair which may be why my squats are getting a lot harder and I’m not able to do the same weight, could this be true?

        • Interesting schedule. It depends what types of HIIT you’re doing and how long the sessions are…?

          • Ollie

            I scheduled it this way because I thought it would be best to let my legs rest 2 days before squats and also to make sure there are not sore.

            I do the HIIT you recommend, 25 minutes on the bikes at a moderately high intensity (keeping my RPM above 100), 30 seconds followed by a minute rest.

          • Makes sense. That’s good on the HIIT. I was afraid you were doing way too much but this should be fine.

          • Ollie

            Just an update I think it was due to a little lack of sleep and it being the end of my cut, got more sleep and started reverse dieting now and it’s got started feeling better.

            Good to know they way I organised HIIT is fine as well thanks!

          • Perfect. Glad to hear that.

  • Zeppelin

    Strong opening paragraph.

  • Bogdan

    This is my body after 1 week of cutting. I’m 6’1 and i have 168 lbs. Should i cut more or bulk? I’m felling very skinny and flat.

  • Richard N

    If an effect is increased blood flow/pump, might it not be better to take after a workout to help drive nutrients into the cells?

    • It can improve workout performance, which is what you really want. That’s why it’s best for pre-workout use.

  • “Do you want rock-freaking-hard biceps and boners!?”
    Ahahahahahahahaha (deep breath) ahhahahahahahahaha 🙂

  • Sara

    I just did a paper regarding nitric oxide and found that it can be incredibly dangerous. Possible strokes and heart attacks can come from too much nitric oxide usage. And that to me seems… idiotic just for a possible benefit to lifting. Good article!

    • Overdosing on anything can be harmful but in moderate dosages NO-boosting supplements are often used to prevent heart attacks and strokes.

  • Nina

    THANK YOU!!!!!!!!!!!! You have no idea how many times I have tried to Google this, only to find articles kind of along the lines of “Nitric Oxide is the best. Just take it. Don’t question it. Oh research, what’s that bro?” Appreciate the studies to back things up here, it really answered a lot of my questions. On a side note, I did take an L-Argignine supplement for several weeks and I never really noticed a significant difference in anything, so I see what you mean here it works for some but not all. Sticking to your “Bigger, Leaner, Stronger” lifting routine is working great for me! Thanks again!!

    • Thanks Nina! Glad you liked the article.

      Yup I’ve taken AAKG in the past and actually noticed a difference so I’m one of the “responders.”

      Keep up the good work and keep me posted!

  • Ahmed

    Take AAKG, it’s like arginine on steroids. Stupid pump bro!


    • Ahmed

      Arginine gives you pumps. If didn’t feel the pump then you didn’t work hard. #marriedtothepumpbro
      Muscleville that’s my home town xD

    • Hahah

  • Mike

    Great article Mike! Thanks for the info. I’m actually in the process of becoming a certified trainer. I hope you don’t mind me using what I learn for you. It’s sad that trainers sell garbage that doesn’t work. Thanks again for the info and inspiration.

  • Brian Giffin

    Mike I’ve been into making my own supliment stacks lately, buying most of my stuff from bulk supliments.
    Have had improvement with 8gms of Citrulline and 5gms of Beta alaine daily.
    I just bought Synephrine and yohimbine for my next cut. Should I continue the Citrulline and Beta alaine as well. Or is that just good when working in a surplus?

    How about Betaine for this as well?


    • Nice! Glad they’ve been working well for you.

      Good call on picking up synephrine and yohimbine for the cut. They’ll definitely help.

      Yep, no need to stop supplementing with citrulline or beta alanine while cutting. They’ll still help! Same as with betaine.

      My pleasure!

  • Benjamin

    Do the nitric oxide patches work? Does the 6-8 gr/ day give your energy? Thank you.

  • zblacktt

    I absolutely positively have MUCH better workouts while taking this supplement. I take 3 pills an hour before my workout and start drinking a NO energy drink 30 mins before and during the workout. As a person that does not do a lot of cardio. I never find myself out of breath or run down. It’s a great pump and continuous flow of energy. I’ve tried a lot over the last 30 years in the gym. If something sucks or does not work. I’d be the first to say it.

  • Precious

    It looks like Nitric Oxide supplement is for the body builders but am not! Just 58 years old woman & I just want to get rid of this fatigue business, should I buy this nitric oxide supplement?

  • Shobhit Raina

    Dude this was a great article. So funny and informative at the same time. Loved it 🙂

  • Mikeg Angelina

    Hi Mike, just wondering Which ratio of citruiline / Malate you recommend, 1:1 or 2:1 ?

  • Spratley Bagweede

    Glad to see someone debunking some aspects of the easy availability of Nitric oxide through dietary supplementation . My insight into the topic is through medical nitric oxide. As a health care provider nitric oxide we use through the inhaled route ONLY. It is a very very controlled manner down to parts per million, through a ventilator. A side effect of the inhaled route is that when it is combined with oxygen there can be can be very toxic NO2 produced. To be more accurate NO2 is always produced because NO is very unstable when mixed with o2.
    So why inhaled ? to reduce the resistance in the pulmonary vasculature.
    So first off, its not easy to get NO to your cells. Second, even if you do , it does not always work. Yup you get it to the cells and nada. And this is with a proven route , through high tech delivery systems.
    Why would it be so easy then with injested supplements?

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