Updated December 2021
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Buying guide for best l-arginine supplements

L-arginine is an amino acid that your body uses to produce proteins. It’s naturally found in poultry, fish, dairy, and red meat. You may be looking for a supplement if you suffer from cardiovascular health problems, erectile dysfunction, or even diabetes. Since L-arginine dilates blood vessels, you can find plenty of uses for the supplement.

Before you add a bottle to your cart, however, don't forget to consider some key factors. If you don't like swallowing pills, you might opt for a powder supplement over pills or capsules. It’s also important to keep taste, natural ingredients, and the potential for stomach upset in mind. Those with particular medical conditions will want to avoid this supplement entirely. Certain medications react poorly with L-arginine, and certain foods can negate its effects (or vice-versa).

L-arginine deficiency is typically detected at birth. But life circumstances may create a need for an L-arginine supplement. If you’re interested in taking a supplement, do consult a physician first. Then, feel free to take a peek at our shopping guide below, so you can make the best-informed purchase.

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Preliminary studies show that L-arginine may be an overall libido booster. It’s often paired with libido-boosting herbs like yohimbe in libido supplements.

Key considerations

As mentioned earlier, L-arginine is an amino acid that the body uses to biosynthesize proteins. It's an essential amino acid, meaning the body does not produce it. Most of us get L-arginine from foods such as chicken, beef, poultry, chickpeas, pumpkin seeds, lentils, and spirulina.

In the body, L-arginine converts to nitric oxide, a neurotransmitter that opens blood vessels and improves circulation to organs throughout the body. L-arginine is also a critical part of the urea cycle, a process through which the body converts ammonia into urea for excretion. For this reason, L-arginine has become a popular supplement for weight lifters and athletes, as increased blood flow means more oxygen reaches the lungs. Those suffering from erectile dysfunction may benefit from L-argnine’s circulation-enhancing properties, too.


L-arginine supplements come in capsule or powder form. While both contain the same product and have roughly the same effectiveness, each has its pros and cons. Powders typically require one dosage per day. This dosage can easily mix into the food or drink of your choice. The average pill requires two to three doses a day, sometimes twice a day. Powders also deliver results more quickly, since L-arginine is easily digested in powder form. Powders are slightly more cost-effective. At a glance, they’re more expensive, but if you’re doing a “per dose” breakdown, pills are more expensive by a few dollars. You don’t need to mix them with water to ingest. And it’s worth mentioning that powders aren’t available in a travel size.

Whether you choose powders or capsules boils down to one factor: personal preference.


It’s safe to say that the average person doesn’t take supplements for the taste. Because L-arginine is particularly alkaline, its taste is rather bitter. The taste is more likely to be noticed in a powder than a capsule, but it’s easy to mask the taste by mixing the powder into juice, smoothies, or other foods.

There are some flavored L-arginine powders available. Citrus is a common additive for taste. Then again, some L-arginine users say the powders taste like nothing at all. If bad taste is a significant deterrent, stick with L-arginine in capsule form.

Free form, HCI, and AAKG

Free form L-arginine is the closest replica of the amino acid found in food. L-arginine isn’t attached to a protein, unlike some amino acids.

L-Arginine HCL combines the amino acid with hydrogen chloride. Hydrogen chloride molecules produce a neutral pH, which helps bitter L-arginine easier on the taste buds. HCl also enhances the ease with which L-arginine is digested in the body.

L-Arginine Alpha Ketoglutarate (also known as AAKG) is a salt of L-arginine and alpha ketoglutaric acid. Alpha ketoglutarate, like K-arginine, is naturally found in the human body, and many believe it supports enhanced athletic performance. AAKG is of particular interest to bodybuilders.


Avoid L-arginine supplements that include preservatives and sugar, which may be unwanted additions to your diet. Several supplements include citrulline, another amino acid that enhances L-arginine’s properties. If the supplement is sold as an overall dietary supplement, it will certainly include extra vitamins like C, D, and K, or folate.

Note that capsules often — but not always — include gelatin. L-arginine supplements should be wheat-, dairy-, and gluten-free unless processed in a factory that houses those products.

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Did you know?
Are you wondering about the difference between arginine and L-arginine? L-arginine is a specific variation of the amino acid, which has over 20 different varieties. The “L” form is arginine as it’s found in the body and in food.

L-arginine supplement prices

As is the case with all vitamins, you truly get what you pay for. L-arginine supplements vary widely in price, from $6 to $35.

Inexpensive: Supplements in the $6 to $10 price range are less likely to have the USDA stamp of approval. The supplement is usually free form and unflavored. You'd be hard-pressed to find a powder in this price bracket. Bottles, on average, include 90 capsules. Keep in mind that if you're taking two to three a day, a bottle should last a month.

Mid-range: L-arginine sold in the $10 to $20 range is more likely to have the organic seal. You can find higher quality 90-capsule bottles and even quantities up to 500. There are some powders in this price range, and there are more supplements that include additional nutrients like citrulline and vitamin D.

Expensive: The $20+ price range begets the best of the best. Here, you'll find flavored supplements, AAKG supplements, supplements with hydrogen chloride, and supplements with a higher concentration of L-arginine.

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  • If you're trying to boost your lysine intake, avoid taking L-arginine simultaneously, as they cancel each other out.
  • Avoid L-arginine supplements (or consult your physician) if you already take blood pressure medication, as it can severely lower your blood pressure.
  • Those with allergies or asthma should consult a physician before starting an L-arginine regimen.

Other products we considered

In addition to our top picks, we’re also fans of BulkSupplements L-Arginine HCL powder. Note that this isn’t free form L-arginine. The hydrogen chloride helps with the taste, making a product that most customers describe as tasteless. BulkSupplements’ powder dissolves easily into any food or drink. Buyers say they’ve noticed better gym workouts and increased endurance, and they love the price. Since doses are rather small, 500 grams goes far. A minority of users complain about the taste, but there are few L-arginine supplements that could be considered pleasant-tasting.

We like Nutricost L-Arginine and L-Ornithine capsules, too. L-Ornithine is another amino acid, though it’s not used to build proteins. Some studies correlate L-Ornithine with reduced ammonia levels, which help prolong exercise. Its effectiveness is, in theory, enhanced by L-arginine and vice versa. This brand of L-arginine seems particularly popular among older buyers who claim the capsules help with blood circulation and joint pain. Gym-goers also seem to notice more efficient gym sessions. It’s recommended for chronic pain sufferers and frequent exercisers. Note that the capsules are large; if swallowing is of concern, these might not be the best choice.

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As a pill, L-arginine should be taken two to three times a day. If you’re taking it to build muscle mass and improve your workouts, try taking it before your workout. L-arginine powders can be taken once a day, depending on how large the dosage is.


Q. Who should avoid L-arginine?
If you take anticoagulants, blood pressure medication, diabetes medication, nitrates, or Viagra, check with your physician before starting L-arginine. In addition, we’d like to reiterate that no one should take this supplement without first checking with their physician.

Q. Does L-arginine cause cold sores?
There’s very little clinical evidence that suggests that L-arginine is a direct cause of cold sores. However, the amino acid L-lysine has been linked to preventing cold sore outbreaks. L-arginine suppresses L-lysine levels, leading some to believe that it’s responsible for cold sore outbreaks.

Q. Can L-arginine help with weight loss?
One 21-day study does link L-arginine to increased weight loss, indicating that the amino acid targets fat mass. Additionally, L-arginine increases blood and oxygen flow throughout the body, leading to optimal workout sessions. This too can contribute to weight loss.

Q. How much L-arginine do you need every day?
The recommended dose of L-arginine varies depending on who is ingesting it. Anywhere from six to 30 grams is safe to take on a daily basis. Those with clogged arteries or heart problems will want to aim for the higher end of that amount. If you're taking L-arginine for erectile dysfunction, for example, under 10 grams should be plenty.

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