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Arginine, which is more commonly called L-arginine when in supplement form, may improve circulation as a precursor to nitric oxide (NO) — a vasodilator that widens your blood vessels, allowing for increased blood flow (1).

For this reason, many athletes use L-arginine for pre-workout energy. It’s also an ingredient in many male enhancement and erectile dysfunction supplements.

Arginine is an amino acid, or building block of protein, that’s found in animal products like meat, fish, and eggs. It’s considered conditionally essential, meaning that most healthy people can synthesize enough of it to meet their needs without supplementing (2).

However, pregnant women, infants, and people with critical illnesses or injuries may require more arginine than they can create on their own (3).

Healthline evaluated the top L-arginine supplements based on these criteria:

  • Third-party testing. A third-party testing facility can ensure the quality and purity of the product.
  • Transparency. The packaging discloses the amount of L-arginine the product supplies.
  • Ingredient quality. The supplement contains high quality ingredients and avoids unnecessary fillers and additives.

Here are the 10 best L-arginine supplements of 2020.

A note on price

General price ranges with dollar signs ($ to $$$) are indicated below. One dollar sign means the product is rather affordable, whereas three dollar signs indicate a higher price.

Generally, prices range from $0.09–$1.33 per serving, or $13.97–$39.99 per container, though this may depend on where you shop.

Formulations for athletes tend to be more expensive.

Note that serving sizes vary by product but are generally 1–4 capsules.

Pricing guide

  • $ = under $0.25 per serving
  • $$ = $0.25–$0.75 per serving
  • $$$ = over $0.75 per serving
Healthline

These supplements contain only L-arginine and are best for people who may need to supplement in instances of pregnancy, injury, or illness.

1. Pure Encapsulations L-Arginine

Pure Encapsulations L-Arginine

Price: $$

Pure Encapsulations is a trusted name in the supplement world and preferred brand among many healthcare providers. The company employs several third-party testing labs to analyze all of its products.

This gluten-free, hypoallergenic supplement provides 1,400 mg of L-arginine per serving. What’s more, the only other ingredient is the softgel capsule.

Shop for Pure Encapsulations L-Arginine online.

2. BulkSupplements L-Arginine Base

BulkSupplements L-Arginine Base

Price: $

This L-arginine supplement from BulkSupplements is free of sugar, soy, preservatives, fillers, and gluten, and the product is third-party tested for quality.

It provides 500 mg of L-arginine per serving and contains a softgel capsule as the only other ingredient.

Shop for BulkSupplements L-Arginine Base online.

3. Thorne Research Perfusia-SR

Thorne Research Perfusia-SR

Price: $$

This sustained-release L-arginine supplement from Thorne Research breaks down slowly to provide a steady, even flow of L-arginine into your system.

It contains 1,000 mg of L-arginine per serving, as well as some fillers like cellulose and other ingredients to support its time-release effects.

The supplement is manufactured in a certified Good Manufacturing Practices (cGMP) facility that meets Food and Drug Administration (FDA) quality standards.

Shop for Thorne Research Perfusia-SR online.

4. Klaire Labs L-Arginine HCl

Klaire Labs L-Arginine HCl

Price: $

Klaire Labs supplements are a favorite among healthcare providers because they’re made with hypoallergenic, high quality ingredients. Its products are manufactured in a cGMP facility that meets FDA guidelines.

This supplement boasts 700 mg of L-arginine per serving and contains the preservative ascorbyl palmitate and anti-caking agent silicon dioxide.

The “HCl” in the name refers to hydrochloride, meaning that this product comprises L-arginine bound with hydrochloric acid. The added hydrochloric acid may help your body better absorb L-arginine (4).

Shop for Klaire Labs L-Arginine HCl online.

5. Horbaach Maximum Strength L-Arginine

Horbaach Maximum Strength L-Arginine

Price: $$

This high dose, vegetarian, and gluten-free L-arginine supplement provides 1,000 mg of L-arginine per capsule. The recommended serving size is 4 capsules, which would provide a whopping 4,000 mg if you take the full amount.

You may want to consult your healthcare provider before taking such a high dose.

This Horbaach product contains a few additives, such as silica and dicalcium phosphate, but the supplement is made in a cGMP facility that meets FDA standards.

Shop for Horbaach Maximum Strength L-Arginine online.

The following products have a few extra ingredients that may make them more suitable for athletes.

6. Havasu Nutrition Extra Strength L-Arginine Nitric Oxide Booster

Price: $$$

This supplement is designed and marketed as a pre-workout energy booster.

It contains 400 mg of L-arginine, along with 400 mg of L-arginine-alpha-ketoglutarate — a specific form that may help boost your energy levels, although current research is mixed regarding its benefits (5).

It also contains citrulline, an amino acid that may help increase both arginine and nitric oxide (NO) production in your body, which is why it’s added to some products marketed as NO boosters. The beetroot powder in this supplement may likewise boost NO production (6).

All Havasu Nutrition supplements are third-party tested as well.

Shop for Havasu Nutrition Extra Strength L-Arginine Nitric Oxide Booster online.

7. Dr. Emil Arginine Plus

Price: $$$

This supplement is designed to be taken as a pre-workout nitric oxide booster.

It contains 1,650 mg of L-arginine — some in the form of L-arginine-alpha-ketoglutarate. It also provides citrulline.

Dr. Emil’s products are third-party tested and manufactured in a cGMP lab.

Shop for Dr. Emil Arginine Plus online.

In combination with other herbal supplements, nutrients, and amino acids, L-arginine is said to naturally boost male enhancement and treat erectile dysfunction (ED).

8. Pure Micronutrients Male Libido Plus

Price: $$$

This supplement from Pure Micronutrients is formulated to help increase male sex drive. In addition to 250 mg of L-arginine, it contains zinc, boron, maca root, horny goat weed, and a variety of other herbs that may help improve male sexual health.

Additionally, it’s completely free of fillers, additives, gluten, and genetically modified (GMO) ingredients.

It has also undergone third-party testing to ensure quality.

Shop for Pure Micronutrients Male Libido Plus online.

9. AZSport Ultimate Male Enhancement

Price: $$

This male enhancement supplement contains 20 mg of L-arginine, along with several other ingredients that may promote male enhancement and sexual performance, such as horny goat weed, maca root, and Panax ginseng.

Keep in mind that this amount of arginine is negligible compared with the average adult’s dietary intake. If you want a higher dose, you’re better off with another product (7).

It’s third-party tested for purity, potency, and safety, and it contains only rice flour as a filler and magnesium stearate as a lubricant.

Shop for AZSport Ultimate Male Enhancement online.

10. Salt Lake Supplements Male Enhancement

Price: $$

This male enhancement supplement contains a similar set of ingredients as the two previous ones on this list, including 250 mg of L-arginine, along with zinc, maca root, and Panax ginseng.

The product is third-party tested and produced in an FDA-approved, cGMP facility. In addition to the active ingredients, it contains the lubricants stearic acid and magnesium stearate, plus the anti-caking agent silicon dioxide.

Shop for Salt Lake Supplements Male Enhancement online.

When shopping for L-arginine supplements, seek out products that have been third-party tested to ensure quality. Although the FDA regulates dietary supplements, it’s minimal compared with the agency’s oversight of prescription medications.

Bear in mind that the rigor of third-party testing varies. The best way to ensure appropriate testing is to look for a label from a certification program like USP, Informed Choice, ConsumerLab, or NSF International.

If a company’s sole assertion of third-party testing is a claim on its website that doesn’t link to a specific certification program, you may want to choose another product.

If you can’t find a product tested by a third party, look for one manufactured at a cGMP facility to ensure that it meets FDA quality standards.

Next, you should choose a product that most closely aligns with your dietary needs, whether that’d be a gluten-free, allergen-free, organic, or GMO-free product.

Because L-arginine is primarily found in animal foods, many L-arginine supplements are not vegetarian. If you’re vegan or vegetarian, look for supplements that are specifically labeled as suitable for these diets.

If ED is your primary concern, you should consult a healthcare provider for more treatment options.

Dosage

Keep in mind that L-arginine isn’t an essential nutrient, so no set dosage guidelines exist. Your healthcare provider may give you dosage guidance if you need it.

Still, a standard supplemental dose of this amino acid is 3–6 grams.

For reference, the average daily arginine intake from food is 4.2 grams for adults. As such, some of the supplements in this list may not boost your current intake by all that much (7).

If you plan to buy a pre-workout or male enhancement supplement, choose one that states how much L-arginine it contains. Avoid those that contain proprietary blends, as this means that the specific amounts of ingredients aren’t disclosed.

Useful supplement shopping guides

Check out these two articles to help make supplement shopping a breeze:

Healthline

L-arginine is an amino acid precursor to nitric oxide, which helps boost circulation and blood flow. As such, it’s commonly used in pre-workout and male enhancement supplements.

Furthermore, pregnant women, infants, and critically injured or ill people may need more arginine than they can produce on their own.

Be sure to talk to your healthcare provider before adding supplements to your routine.