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• Nitric oxide is a vasodilator — it increases blood flow by relaxing the inner muscles of your blood vessels, allowing them to widen and let more blood through. Blood carries oxygen and nutrients, and increasing blood flow throughout your body has major effects on your performance.
• Boosting nitric oxide increases exercise capacity for both endurance training and weightlifting. Nitric oxide supplements can also speed up muscle recovery by up to 40 percent.
• Nitric oxide supplements decrease blood pressure, too. They can make a big difference in cardiovascular performance if you have hypertension.
• Erectile dysfunction medication like Viagra works by increasing nitric oxide levels to stimulate blood flow. If you want firmer erections, you don’t need a prescription; research shows that nitric oxide-boosting supplements have similar effects on erection quality.
• Read below for ways to increase nitric oxide levels naturally, plus a list of nitric oxide supplements and dosages.

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Nitric oxide supplements have been hugely popular in the bodybuilding community for more than two decades. You can feel them working — increased blood flow, a better “pump” in your muscles while you lift, and faster recovery all make nitric oxide a valuable addition to your pre-workout routine.

Nitric oxide has benefits in the bedroom, too. Increased blood flow can make a big difference in sexual performance.

Here’s everything you need to know about nitric oxide: what it is, how it benefits you, and the best ways to boost it for better performance.

Related: Upgrade Your Energy, Optimize Your Supplements

What is nitric oxide?

Nitric oxide is a vasodilator — it increases blood flow by relaxing the muscles along the inside wall of your blood vessels, allowing the vessels to widen.

Blood carries nutrients and oxygen, so increased blood flow often provides your cells with precious raw materials and improves performance. Nearly every cell in your body can produce nitric oxide. Your muscles, heart, and penis (if you have one) are all particularly sensitive to nitric oxide, and derive a lot of benefit from increased blood flow.

Nitric oxide benefits 

Increasing nitric oxide can give you a boost in the gym, help your muscle recover faster, normalize blood pressure, and make sex more enjoyable. Here’s a closer look at each of the benefits of nitric oxide.

Nitric oxide increases exercise capacity

There’s a reason nitric oxide supplements have been popular with bodybuilders for more than 20 years — they’re some of the few workout supplements that actually work. Boosting nitric oxide carries more oxygen to your muscles, increasing their ability to make ATP (energy) and giving you more physical endurance[ref url=”https://journals.lww.com/nsca-jscr/Citation/2018/06000/The_Effect_of_Nitrate_Supplementation_on_Exercise.38.aspx”][ref url=”https://www.ncbi.nlm.nih.gov/pubmed/23580439″]. Nitric oxide is good for  both aerobic training like running[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/27600147″] and brief, intense exercise like weight lifting or sprinting[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/20386132″][ref url=”https://www.ncbi.nlm.nih.gov/pubmed/26023227″].

Enhances muscle recovery (a lot)

Nitric oxide also speeds up recovery and prevents muscle soreness. People who took L-citrulline, a compound that increases nitric oxide production, saw a 40 percent decrease in muscle soreness after an intense weight-training session, compared to people who took placebo[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/20386132″]. You’ll read more about L-citrulline below; it’s one of the best supplements to increase nitric oxide.

Nitric oxide for high blood pressure

Low nitric oxide can be a cause of hypertension (high blood pressure)[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/17170603″] — without enough nitric oxide, your blood vessels stay more constricted, which increases pressure inside the vessels (the same way narrowing a hose increases water pressure).

Boosting your nitric oxide levels relaxes your blood vessels and allows them to widen, which can bring your blood pressure back to normal[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/25421976″][ref url=”https://www.ncbi.nlm.nih.gov/pubmed/25683748″][ref url=”https://www.ncbi.nlm.nih.gov/pubmed/26023227″].  

Nitric oxide for stronger erections

If you’re a guy, boosting nitric oxide can improve your erection quality. In fact, Viagra and Cialis, the two most popular erectile dysfunction medications, both work by stimulating nitric oxide pathways in the penis, relaxing blood vessel muscles so more blood can flow through.

Good news: if you have occasional trouble in the bedroom, you don’t need a prescription to get a stronger erection. A lot of men with erectile dysfunction have low L-arginine or L-citrulline, two amino acids that increase nitric oxide production[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/28178400″]. Supplementing with either one (or both) can improve erection quality and duration[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/21195829″][ref url=”https://www.ncbi.nlm.nih.gov/pubmed/12851125″]. You may also be able to get firmer erections by eating more foods that contain L-citrulline or L-arginine[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/27934657″]. Good options are listed below.

How to increase nitric oxide

There are a lot of different ways to increase nitric oxide levels in your blood. Beets are rich in nitrates (precursors to nitric oxide), and beetroot juice is one of the most popular choices to increase nitric oxide. But beets contain a high amount of sugar, so they’re classified as a “suspect” food on the Bulletproof Diet. You’re better off choosing one of these options instead.

Sun exposure

Direct sunlight on your skin triggers bodywide nitric oxide production[ref url=”https://www.jidonline.org/article/S0022-202X(15)36878-0/abstract”]. Spend 15-30 minutes in the sun with as much skin exposed as possible. Make sure you stop before you burn; the right amount of sunlight is amazing for you in all kinds of ways, but if you push it to the point where you get a sunburn, you increase your risk of skin cancer by a lot.

L-citrulline

L-citrulline is an amino acid (a building block of proteins) that increases blood nitric oxide levels. Studies have looked specifically at using L-citrulline to increase erection firmness[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/21195829″] and muscle recovery[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/20386132″], with excellent results for both. Take 1000-2000 mg of L-citrulline for erectile dysfunction, or 3000-5000 mg of L-citrulline for enhanced exercise performance and recovery.

L-arginine

This is another amino acid that may increase nitric oxide. Note that results are mixed when it comes to L-arginine — while many studies say it does increase nitric oxide levels[ref url=”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2860344/”][ref url=”https://www.ncbi.nlm.nih.gov/pubmed/15638817″], a few studies have found no effect[ref url=”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3489573/”], or that L-citrulline works better[ref url=”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5368575/”]. Most studies suggest 2000-3000 mg of L-arginine, taken two to three times a day.

Pycnogenol

Pycnogenol is an extract from pine trees that increases nitric oxide levels[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/12851125″][ref url=”https://www.ncbi.nlm.nih.gov/pubmed/14659974″]. It also improves attention and overall mental performance[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/22108481″]. Studies use a dose of 100-200 mg, taken twice daily.

Nitrate oxide foods

Nitrate is a precursor to nitric oxide, and eating foods high in nitrates can increase nitric oxide levels throughout the body[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/23596162″][ref url=”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5350612″]. A lot of vegetables are rich in nitrate. Some of the best sources are celery, spinach, chard, arugula, and cabbage[ref url=”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5412236/”]. Cured meats are also a good source of nitrates, although you always want to get nitrates alongside antioxidants, because nitrates can degrade into carcinogens called N-nitroso compounds[ref url=”https://www.ncbi.nlm.nih.gov/pubmed/10415436″]. Fortunately, vegetables are high in antioxidants, so if you get your nitrates from vegetables, you’re fine. If you eat cured meats, get some veggies alongside them.

Increasing nitric oxide is a powerful way to get more out of your workouts and recover faster, and to enhance your sex life. Give it a try and see how you feel.

Read next: 6 Workout Supplements That Actually Work