Nitric Oxide Supplements for Erections: Do L-Arginine and Beetroot Work?
An erection depends on blood flow, and blood flow depends on nitric oxide, the molecule that tells your arteries to relax and open. That is why so many men's supplements list L-arginine, L-citrulline and beetroot. The question is whether the versions in a capsule or gummy do anything, and the honest answer comes down to dose.
How nitric oxide drives an erection
When you are aroused, the nerves and the lining of the penile arteries release nitric oxide. That relaxes the smooth muscle in the artery walls, the arteries widen, and blood fills the penis faster than it can drain. As men age, the artery lining makes less nitric oxide on demand, which is a big part of why erections get softer. The idea behind these supplements is to feed that pathway more raw material.
Does L-arginine work for ED?
Short answer: at gram level doses there is human evidence. At the amounts in most blends there is not.
L-arginine is the direct precursor your body uses to make nitric oxide. A 2019 systematic review and meta analysis of randomized trials in men with mild to moderate erectile dysfunction (PubMed 30770070) found that arginine supplements at 1,500 to 5,000 mg a day improved erectile function compared with placebo or no treatment. A separate 2021 meta analysis of four trials (PubMed 33587304) compared L-arginine with prescription options and found that a prescription option alone worked better than L-arginine alone, and that combining the two worked better than either one. The catch is the dose. The trials that worked used 1500 to 5000 mg a day. A blend that lists 50 or 100 mg is not in the same conversation.
L-citrulline: the more efficient route
Taken by mouth, a lot of L-arginine is broken down in the gut and liver before it reaches the bloodstream. L-citrulline sidesteps that. It is absorbed well, then converted to arginine in the kidneys, so it raises blood arginine levels more reliably than arginine itself. A small 2011 single blind trial in 24 men with mild ED (PubMed 21195829) gave them a placebo for a month and then 1500 mg of L-citrulline a day for a month. Erection hardness improved from mild ED to normal in 12 of the 24 men on citrulline, against 2 of the 24 on placebo, and the number of intercourses per month went up, with no adverse events. It is a small study and the placebo month was not randomized, but it points the same direction as the arginine data, with a more practical dose.
Does beetroot help erections?
Beetroot is one of the richest food sources of dietary nitrate, which gut bacteria and the body convert into nitric oxide by a separate route from arginine. Beetroot supplementation reliably improves blood flow, lowers blood pressure a little, and improves exercise endurance. It has not been tested directly for erections, so applying it there is reasonable but unproven. What is clear is the amount. The blood flow studies use beetroot juice or concentrate equal to a large glass, delivering hundreds of milligrams of nitrate. The 50 mg of beet root powder in a typical gummy is a rounding error next to that.
The dose problem, in one paragraph
Every supplement in this category leans on the nitric oxide story, and the science behind the story is sound. The problem is that products routinely list these ingredients at 50 to 100 mg when the research used 1.5 to 5 grams, which is 15 to 100 times more. That is not an accident. Grams of arginine or citrulline do not fit in a gummy alongside six other ingredients. So if boosting nitric oxide is your goal, a single ingredient powder at a researched dose, or actual beetroot in your diet, will do more than a multi ingredient blend.
Looking at a specific product? The IronPulseX gummy is one of the few that prints its doses, so you can see exactly how its 50 mg of L-arginine and 50 mg of beet root stack up against the research above. Our review breaks down all seven ingredients.
For the herbal side of these formulas, maca, ginseng, tongkat ali and horny goat weed, see the ingredient breakdown. And if the underlying issue is firmness, start with why erections get softer after 40.
If you came here after seeing the viral "blue salt trick," the nitric oxide story above is why some blue salt supplements list beetroot or amino acids alongside the salt. See the blue salt trick for men: what it claims and what the research says.
Common questions
Does L-arginine work for ED?
For mild to moderate erectile dysfunction, a 2019 meta analysis of randomized trials found that arginine supplements at 1,500 to 5,000 mg a day improved erectile function compared with placebo or no treatment. A 2021 meta analysis found that a prescription option alone worked better than L-arginine alone. Amounts under about 1500 mg a day, which is what most blends contain, do not have the same support.
Is L-arginine or L-citrulline better for erections?
L-citrulline is absorbed better and raises blood arginine levels more reliably than L-arginine itself. A small 2011 trial found that 1500 mg of L-citrulline a day improved erection hardness in men with mild ED. If you are choosing one, citrulline is the more efficient route to the same nitric oxide pathway.
Does beetroot help erections?
Beetroot is high in nitrate, which the body converts to nitric oxide, and it measurably improves blood flow and exercise performance. It has not been tested directly for erections, so the link is reasonable but unproven. The servings used in blood flow studies are far larger than the 50 mg of beet root found in a typical gummy.
Medical note. This article is general information, not medical advice. L-arginine can lower blood pressure and interact with blood pressure and heart medication. Talk to your doctor before starting a supplement, especially at gram level doses.
Affiliate disclosure. If you buy through links to a product on this site, we may earn a commission from the seller. You pay the same price, and it does not change what we write.
References
Rhim HC, Kim MS, Park YJ, et al. The Potential Role of Arginine Supplements on Erectile
Dysfunction: A Systemic Review and Meta-Analysis. The Journal of Sexual Medicine,
2019.
PubMed 30770070
Xu Z, et al. Comparison of efficacy and safety of daily oral L-arginine and PDE5Is alone
or combination in treating erectile dysfunction: a systematic review and meta-analysis of
randomised controlled trials. Andrologia, 2021.
PubMed 33587304
Cormio L, et al. Oral L-citrulline supplementation improves erection hardness in men
with mild erectile dysfunction. Urology, 2011.
PubMed 21195829