From sham honey-based erectile dysfunction fighters to legit testosterone boosters—like ashwagandha—there’s no dearth of supplements that claim to boost your libido, better your sex life, and supercharge your erections.
The latest contender: Nitric oxide (NO). And while it’s tempting to dismiss anything lauded by DIY testers on Reddit, there’s credible research that NO can help with your sex life by strengthening your erections and improving your libido.
Your body naturally produces nitric oxide, but like other biological compounds and chemicals (like testosterone, NAD, and glutathione), production declines with age. “By 40 years old, you lose 50 percent of your nitric oxide levels”, says Erich Acebedo, M.D.
That means poorer blood flow, which can equal weaker erections and a lackluster libido.
If you’re looking to give nitric oxide a try (and btw, it’s different from nitrous oxide, the whip-its gas Bob Saget and John Stamos used to get high while filming Full House), here’s everything you need to know.
What Does Nitric Oxide Do?
NO is a molecule that’s produced naturally by your body. Its main role is a vasodilator; it relaxes the inner muscles of your blood vessels (including the ones in your penis) allowing them to widen. This increases blood flow and reduces blood pressure, Acebedo says.
NO also increases oxygen to your brain—both your big one and your little one, which makes it key for sexual arousal.
Signs you’re not getting enough NO
There are no outward signs of low nitric oxide levels. But over time, depleted NO levels can manifest as chronic diseases, like high blood pressure, Alzheimer’s, and erectile dysfunction, says Acebedo.
The root cause of low NO levels is damage to the endothelial lining—a thin membrane inside your blood vessels—says Acebedo. “A sedentary lifestyle and eating too much processed foods and sugar can destroy your lining. Environmental toxins and infections, like COVID, also cause damage,” he says.
“You can take an at-home saliva test to check your levels,” he says. His pick: the Berkeley Life Nitric Oxide Saliva Test Strips.
Does Nitric Oxide Help Sexually?
Nitric oxide acts on your body via three pathways to improve blood flow, desire, and arousal, says Acebedo: the arginine pathway, the neuronal pathway, and the endothelial pathway.
Let’s start with your arginine pathway.
When you take in L-citrulline—a non-essential amino acid found in foods like watermelon, or from supplements—your body turns it into an amino acid called L-arginine.
L-arginine combines with oxygen in your bloodstream to create nitric oxide, Acebedo says. (One 2019 study actually found arginine supplements were effective for treating mild to moderate ED (1)).
Your brain also creates nitric oxide via the neuronal pathway. It’s complicated business, but in a nutshell: nerve receptors that send signals from one part of your brain to the other release calcium which triggers the production of nitric oxide in your blood, which increases libido and stimulates sexual desire.
Your endothelial pathway, which lines your blood vessels and increases blood flow is also responsible for increasing the elasticity of your penis’s dorsal artery—a major source of blood for erectile tissue—to help with ED and provide stronger erections, Acebedo says.
Can nitric oxide supplements treat premature ejaculation?
Yes, says Acebedo. Researchers haven’t sussed out exactly how yet but one study published in the journal Andrologia confirms that premature ejaculation is linked to lower levels of nitric oxide (2).
That suggests getting more NO could combat the problem, says Acebedo.
Nitric Oxide and Low T
It’s common to think that nitric oxide boosts your testosterone levels, but it’s actually reverse, Acebedo says. Testosterone can boost your NO levels.
“Higher levels of testosterone repair the cell lining of your blood vessels,” he says. (Remember, damage to your blood vessels lowers nitric oxide.)
If you have low T, “testosterone replacement therapy will increase your testosterone levels and in turn, increase your levels of nitric oxide,” Acebedo says.
But don’t rely on TRT alone. “Making lifestyle changes in tandem with TRT, like getting more exercise and eating less processed food, give you the biggest NO increase,” Acebedo says.
How to Increase Nitric Oxide in Your Body
Eat nitrate-rich foods
Kale, cabbage, spinach, and beets are rich in nitrates, which, via the nitrate-nitrite pathway, help your body produce nitric oxide and widen your blood vessels, Acebedo says. The wider your blood vessels are, the more blood can flow to your genitals for better erections.
Aim for five servings of green vegetables per day, says Acebedo.
Feel free to go with the cheaper option: Organic vegetables have lower nitric oxide levels than conventionally-grown veggies, Acebedo says. Researchers suspect the soil quality is lower with not enough nitrates.
Exercise stimulates your endothelial lining for increased blood flow, says Acebedo. One 2022 study found exercise can significantly increase nitric oxide levels regardless of how long you work out for you and whether you do aerobic training (AT) or high-intensity interval training (HIIT) (3).
A review published in The Journal of Sports Medicine and Physical Fitness found concrete evidence that physical activity enhances nitric oxide production and could increase NO (4). While the study didn’t examine whether this could help your erections, because exercise increases blood flow, it has both cardiovascular and sexual benefits, says Acebedo.
Take NO supplements
Nitric oxide supplements are effective, Acebedo says, but it’s important to find reputable ones and to limit the dose to 2,000 mg of nitrate per day.
Here’s the ones he offers patients—and uses himself.
HumanN Super Beets
Dr. Acebedo mixes HumanN Super Beets with Legion Pulse pre-workout to increase blood flow to his muscles during exercise.
Getting a better workout may strengthen erections. One 2018 study found 160 minutes of weekly exercise over six months decreases erectile problems in men with ED caused by inactivity, and health conditions including obesity and hypertension (5).
HumanN Neo40 and Berkeley Life Professional Nitric Oxide Support
Take these before bed. “NO supplements can improve your sleep because they stimulate blood flow to your brain to release melatonin,” Acebedo says.
Why that’s good for your penis: Poor sleep may put you at a higher risk for ED. One 2020 review found poor sleep in men negatively impacts symptoms of erectile dysfunction, hypogonadism, and infertility (6).
Bask in infrared light
Infrared light activates your blood vessel cells within your endothelial lining to stimulate nitric oxide production, Acebedo says.
Research suggests red light may also help curb inflammation and improve your immune response. Inflammation has been tied to an increased risk of erectile dysfunction as well as endothelial dysfunction—a type of coronary artery disease—caused by ED (7), while studies suggest increasing your immune system could improve sexual dysfunction (8).
When you kill germs that cause bad breath, they can annihilate good bacteria in your mouth that convert nitrate to nitrite (which your stomach breaks down into nitric oxide).
Take deep breaths through your nose
Inhale. And exhale. You just increased nitric oxide production.
Researchers suspect that deep breaths through your nose can stimulate neuronal passages to boost nitric oxide, says Acebedo.
Deep breaths also increase the amount of oxygen you take in. And remember, oxygen is needed to convert citrulline to arginine to then produce nitric oxide, Acebedo says.
The Bottom Line
Nitric oxide is produced through complex pathways in your body to stimulate libido and improve erections. Despite its stark decline after 40, there are plenty of ways to increase NO in your body including exercise, leafy greens, supplements, and deep breathing.