L-arginine is an amino acid produced by the body and derived from foods. It has been popularized as a supplement in the past few decades as a way to boost cardiovascular and fertility. But does the research back the hype?
In this guide, we’ve laid out the best l-arginine supplements. Farther down, we’ve summarized the research on l-arginine’s benefits and common dosages.
|Best Overall: NOW Supplements – Pure L-Arginine Capsules||$12.83 Buy on Amazon|
|Best Cream: BulkSupplements – Pure L-Arginine Powder (1 kg)||$27.96 Buy on Amazon|
|Best Value: Preventix – Magnesium L-Arginine Cream||$29.95 Buy on Amazon|
Top 3 L-Arginine Supplements
Best L-Arginine Supplement Overall
This is the go-to l-arginine supplement. NOW Foods is a reputable health supplement brand, and this pick is no different. It’s one of the most popular and highly-reviewed l-arginine supplements on Amazon.
Best Value L-Arginine Supplement
If you’re looking for the most bang for your buck, this is it. This pure l-arginine powder is available in bulk, making it one of the most inexpensive options per serving.
Best L-Arginine Cream
Some people prefer to apply l-arginine topically, and this l-arginine cream does just the trick. It’s made with magnesium harvested from the Dead Sea to support healthy skin. It’s soothing to the skin and scent-free.
Studies have found correlations between l-arginine supplementation benefits like reduced blood pressure and improve fertility. We’ve summarized the research below.
- L-Arginine Blood Pressure Effects
Research has shown that l-arginine may be effective in lowering blood pressure.
In the early 1990s, it was discovered that taking l-arginine leads to increased production of nitric oxide inside the blood vessels.1The L-Arginine-Nitric Oxide Pathway Nitric oxide, in turn, causes vascular tissue (such as veins and arteries) to relax.2Vascular endothelial cells synthesize nitric oxide from L-arginine This process alone indicates that l-arginine may have an impact on blood pressure.
One study examined the cardiovascular effects of l-arginine on fifteen patients with sepsis syndrome, a condition characterized by inflammation following extreme infection.3L-arginine pathway in the sepsis syndrome. When each group was administered l-arginine, researchers noted a short-term decrease in blood pressure. They also noted an increase in cardiac output, the measure of blood volume pumped in liters per minute.
Another study demonstrated the mechanisms by which l-arginine reduces blood platelet aggregation.4An L-arginine/nitric oxide pathway present in human platelets regulates aggregation In plain English, the study indicates that l-arginine may help reduce the risk of blood clots by inhibiting certain blood-clotting mechanisms.
- Immune System Support
Research has shown that l-arginine supplementation can support T cell function.5Regulation of immune responses by L-arginine metabolism T cells are a type of white blood cell that play a role in the immune system. The cited study shows that supplementing l-arginine may lead to an increase in immune system function.
- L-Arginine Fertility Improvement
One study sought to examine the effects of l-arginine and pycnogenol in men with mild erectile dysfunction and low sperm count and motility.6Improvement of seminal quality and sexual function of men with oligoasthenoteratozoospermia syndrome following supplementation with L-arginine and Pycnogenol® At two months of treatment, the researchers measured significantly increased sperm concentration. They also noted a significant reduction in erectile dysfunction.
- L-Arginine Weight Loss Impact
One study performed on pigs provides some promising insight into l-arginine’s weight loss effects.7Dietary l-arginine supplementation increases muscle gain and reduces body fat mass in growing-finishing pigs The study found that after 60 days of supplementation, pigs that were given l-arginine demonstrated a 5.5% increase in muscle mass and an 11% decrease in fat mass compared to a control. These findings indicate that l-arginine may be effective in promoting weight loss (specifically, fat loss).
Unfortunately, we need more human studies on l-arginine and weight loss. Further research is needed before we can know with more certainty whether l-arginine may be effective for weight loss.
L-Arginine and Pycnogenol
Several studies have demonstrated that l-arginine and pycnogenol may be effective reducing erectile dysfunction and improving fertility.
L-arginine and pycnogenol together have been studied as a means to affect erectile dysfunction.8Treatment of Erectile Dysfunction with Pycnogenol and L-arginine Proper erectile function is supported by nitric oxide, which can be increased by both l-arginine and pycnogenol individually. The study found that supplementing l-arginine and pycnogenol together may significantly improve sexual function in men with erectile dysfunction.
A slew of other studies have similarly found that supplementing l-arginine and pycnogenol together may be effective in men with mild to moderate erectile dysfunction.9Clinical Assessment of a Supplement of Pycnogenol® and l‐arginine in Japanese Patients with Mild to Moderate Erectile Dysfunction
As mentioned above, one study found that l-arginine and pycnogenol together may improve sperm count.10Improvement of seminal quality and sexual function of men with oligoasthenoteratozoospermia syndrome following supplementation with L-arginine and Pycnogenol The study noted a significant improvement in sperm concentration and erectile function after two months of supplementation.
For more information on pycnogenol, refer to our complete pycnogenol guide.
This is a top-notch blend of l-arginine, citrulline, and pine bark extract (which is similar in composition to pycnogenol).
Pine bark extract
L-Arginine and Alpha-Ketoglutarate
L-arginine and alpha-ketoglutarate are sometimes marketed as fitness and/or athletic performance enhancers, but there is currently not enough evidence to support this. One study did find that l-arginine and alpha-ketoglutarate supplementation resulted increased bench press one-rep-max.11Pharmacokinetics, safety, and effects on exercise performance of l-arginine α-ketoglutarate in trained adult men However, other research has found no impact of l-arginine and alpha-ketoglutarate on muscle performance or cardiovascular condition.12Acute L-arginine alpha ketoglutarate supplementation fails to improve muscular performance in resistance trained and untrained men13Effects of 7 Days of Arginine-Alpha-Ketoglutarate Supplementation on Blood Flow, Plasma L-Arginine, Nitric Oxide Metabolites, and Asymmetric Dimethyl Arginine After Resistance Exercise
L-Arginine and L-Citrulline
One study looked at the effects of pycnogenol, l-arginine, and l-citrulline on sperm quality.14Sperm quality in men is improved by supplementation with a combination of L-arginine, L-citrullin, roburins and Pycnogenol®. The study examined the effects of these substances on 50 men with poor sperm quality over one month of supplementation. At the end of the trial, sperm volume, concentration, motility, and vitality were significantly improve compared to placebo. These findings indicate that l-arginine and l-citrulline together with pycnogenol may be effective in improving sperm quality.
Each twp-capsule dose contains a 400 milligrams of l-arginine and l-citrulline each. Perfect for taking both supplements together.
Beet root powder
There is currently no officially recommended l-arginine dosage.
Some of the above-cited research used an l-arginine dosage of roughly 700 milligrams daily. Many users take up to 2 or 3 grams daily with no notable side effects, but little research has been performed on doses that high.
Research has shown that l-arginine may be effective in improving a handful of health factors, including blood pressure and fertility. In particular, studies have shown l-arginine and pycnogenol together can be effective in improve fertility and erectile function.
For further reading, our complete pycnogenol guide details a slew of research-backed health benefits of the ancient Indian herb, including cardiovascular, skin, and brain support.