NOW L-Arginine 500 mg

• 500 mg pharmaceutical-grade L-Arginine per capsule
• 1,000 mg L-Arginine per 2-capsule serving
• Conditionally essential amino acid
• Free-form L-Arginine for convenient supplementation
• Important precursor to nitric oxide (NO)*
• Supports normal blood vessel relaxation and circulation*
• Participates in healthy vascular signaling*
• Supports normal protein synthesis and production*
• Important for nitrogen metabolism and the urea cycle*
• Participates in metabolic pathways involved in ammonia removal*
• Supports normal cellular and metabolic function*
• Convenient vegetarian capsules
• Pharmaceutical-grade amino acid ingredient
• Non-GMO
• Vegetarian and vegan
• Manufactured without wheat, gluten, soy, milk, eggs, fish, shellfish, or tree nut ingredients
• Halal and Kosher
• GMP Quality Assured
• 100 vegetable capsules per bottle
• 50 servings per container

• Nitric Oxide Production: L-Arginine serves as a substrate for nitric oxide synthase, an enzyme responsible for producing nitric oxide. This signaling molecule contributes to normal blood vessel relaxation and vascular function.*
• Healthy Circulation: Nitric oxide plays an important role in regulating vascular tone and supporting normal blood flow throughout the body. L-Arginine supplies a precursor involved in this natural process.*
• Cardiovascular Wellness: By participating in nitric oxide production, L-Arginine contributes to pathways involved in healthy endothelial function and normal cardiovascular physiology.*
• Protein Synthesis: L-Arginine is an amino acid used in protein production and participates in normal tissue maintenance, growth, and cellular processes.*
• Nitrogen Metabolism: L-Arginine plays a central role in the urea cycle, helping the body convert ammonia produced during normal protein metabolism into urea for excretion.*
• Exercise & Muscle Function: L-Arginine is commonly included in sports nutrition formulas because of its role in nitric oxide production and vascular signaling. Research into exercise-performance improvements from oral L-Arginine supplementation has produced mixed results.*
• Conditionally Essential Nutrition: Although the body can normally produce L-Arginine, requirements may increase during certain periods of physiological stress, growth, or recovery.*
• Convenient Amino Acid Support: Each capsule contains 500 mg of free-form L-Arginine, allowing flexible serving amounts without measuring powders or preparing a beverage.

• L-Arginine (Free-Form) — 1,000 mg per 2 Capsules: A conditionally essential amino acid involved in nitric oxide synthesis, urea metabolism, protein production, and normal cellular function. L-Arginine serves as a precursor to nitric oxide, which participates in healthy blood vessel relaxation and vascular signaling. It also contributes to the urea cycle, helping the body process nitrogen-containing waste products. NOW uses pharmaceutical-grade, free-form L-Arginine, providing 500 mg per vegetable capsule.*

L-Arginine is a conditionally essential amino acid that participates in several important biochemical pathways throughout the body. One of its best-known functions is serving as a precursor to nitric oxide (NO), a signaling molecule produced through the action of nitric oxide synthase enzymes. Nitric oxide helps regulate vascular tone by signaling smooth muscle cells within blood vessel walls to relax, contributing to normal circulation and blood vessel function. L-Arginine also plays a central role in the urea cycle, a metabolic pathway that converts ammonia generated during protein and amino acid metabolism into urea for elimination through the kidneys. In addition, L-Arginine is used in normal protein synthesis and contributes to processes involved in cellular maintenance and tissue function. Although the body can produce L-Arginine under ordinary conditions, it is considered conditionally essential because requirements may exceed endogenous production in certain physiological circumstances. NOW L-Arginine supplies pharmaceutical-grade, free-form L-Arginine in a convenient capsule format to complement dietary amino acid intake and support these normal metabolic functions. The extent to which supplementation increases nitric oxide availability or improves exercise performance depends on individual circumstances and has not been established specifically for this finished product.*

• Pharmaceutical-Grade L-Arginine: NOW identifies the L-Arginine used in this formula as pharmaceutical grade.
• Free-Form Amino Acid: Supplies L-Arginine as an individual amino acid rather than as part of an intact protein powder.
• 500 mg Per Capsule: Each vegetable capsule provides a clearly disclosed amount of L-Arginine.
• 1,000 mg Per Serving: The Supplement Facts panel identifies two capsules as one serving.
• Single-Active-Ingredient Formula: Focuses on L-Arginine without additional amino acid blends, stimulants, or proprietary performance complexes.
• Nitric Oxide Precursor: Provides an amino acid directly involved in the body's normal production of nitric oxide.
• Multiple Metabolic Roles: L-Arginine participates in nitric oxide synthesis, protein production, and the urea cycle.
• Vegetarian & Vegan: Uses hypromellose vegetable cellulose capsules rather than animal-derived gelatin.
• Non-GMO: Identified as a Non-GMO supplement.
• Common Allergen Exclusions: Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, or tree nut ingredients. Produced in a GMP facility that also processes ingredients containing these allergens.
• Halal & Kosher: Product packaging identifies Halal and Triangle K Kosher status.
• GMP Quality Assured: NOW identifies Intertek GMP certification covering manufacturing procedures, laboratory testing methods, potency, stability, and formulation controls.
• Manufactured & Quality Tested by NOW Foods: Produced under NOW's established supplement quality program.
• Convenient Capsule Format: Provides flexible daily supplementation without measuring loose powder.
• 100 Vegetable Capsules: Supplies 50 labeled two-capsule servings per bottle.

• Adults seeking supplemental L-Arginine as part of their daily nutrition routine
• People interested in supporting normal nitric oxide production*
• Adults seeking nutritional support for healthy vascular function*
• Individuals interested in amino acids involved in normal cardiovascular physiology*
• Fitness enthusiasts researching nitric oxide precursor supplements
• Adults looking to support normal protein and nitrogen metabolism*
• Those interested in the role of amino acids in normal cellular function*
• People who prefer single-ingredient amino acid supplements rather than complex blends
• Individuals who prefer vegetarian capsules instead of amino acid powders
• Vegetarian and vegan supplement users
• Those seeking a Non-GMO amino acid formula
• Adults who value pharmaceutical-grade ingredients and GMP quality controls
• Not suitable for individuals with certain cardiovascular, renal, or other medical conditions identified in the product warnings without appropriate medical guidance

• Take 2 capsules twice daily as needed, according to the manufacturer's directions.
• Take between meals or at bedtime.
• Consume with at least 8 oz of water or juice to facilitate absorption.
• Each 2-capsule serving provides 1,000 mg of L-Arginine.
• The manufacturer's twice-daily suggested intake provides a total of 2,000 mg of L-Arginine from 4 capsules.
• Store in a cool, dry place after opening.
• Natural color variation may occur.
• Warnings: Take this product with at least 8 oz of water or juice. For adults only. Not for pregnant or nursing women. Consult a physician if taking medications, especially antihypertensives, anticoagulants, or antidiabetic drugs; if you have a medical condition, particularly asthma or renal disease; or if planning surgery. This product should be avoided by people with glaucoma or herpes simplex unless otherwise prescribed by a physician. Do not use if you have had a myocardial infarction or have established coronary artery disease. Keep out of reach of children.

Hypromellose (cellulose capsule), stearic acid (vegetable source), and silicon dioxide.

• What is NOW L-Arginine 500 mg?
  NOW L-Arginine 500 mg is a single-amino-acid dietary supplement that provides pharmaceutical-grade, free-form L-Arginine to support nitric oxide production, normal vascular function, protein synthesis, and nitrogen metabolism.*
• How much L-Arginine is in each capsule?
  Each vegetable capsule contains 500 mg of free-form L-Arginine.
• How much L-Arginine is in one serving?
  The Supplement Facts panel lists 2 capsules per serving, providing 1,000 mg (1 g) of L-Arginine.
• What is L-Arginine?
  L-Arginine is a conditionally essential amino acid involved in protein synthesis, nitric oxide production, and the urea cycle. It is naturally found in protein-containing foods and can also be synthesized by the body.
• What does conditionally essential mean?
  A conditionally essential amino acid is one that the body can normally produce in sufficient amounts but may require in greater quantities during certain physiological conditions, such as growth or significant metabolic stress.
• What is nitric oxide?
  Nitric oxide (NO) is a signaling molecule naturally produced by the body. It participates in several biological processes, including blood vessel relaxation, vascular signaling, and regulation of normal blood flow.
• How does L-Arginine support nitric oxide production?
  L-Arginine serves as a substrate for nitric oxide synthase enzymes, which convert L-Arginine into nitric oxide and L-citrulline. Nitric oxide subsequently participates in signaling pathways involved in vascular relaxation.*
• Does L-Arginine support healthy circulation?
  L-Arginine is involved in nitric oxide production, which supports normal vascular function. However, taking additional L-Arginine does not guarantee improved circulation, and research findings vary by dosage and individual health status.*
• Can L-Arginine support cardiovascular health?
  L-Arginine participates in nitric oxide-related pathways important for vascular function. However, it is not a substitute for cardiovascular treatment, and the product label specifically advises against use following myocardial infarction or in established coronary artery disease.
• Can L-Arginine improve muscle pumps during workouts?
  L-Arginine is commonly used in sports nutrition because it is a nitric oxide precursor. However, studies of oral L-Arginine for exercise blood flow and muscle pumps have produced inconsistent results, and benefits are not guaranteed.
• Does L-Arginine increase exercise performance?
  Research examining L-Arginine supplementation for exercise performance has produced mixed findings. Although L-Arginine participates in nitric oxide production, improved endurance, strength, or training performance has not been established for this particular product.
• What role does L-Arginine play in protein synthesis?
  L-Arginine is an amino acid used by the body as a building block for proteins. It contributes to normal protein production and other cellular processes.*
• What is the urea cycle?
  The urea cycle is a metabolic process that converts potentially harmful ammonia, produced during normal amino acid metabolism, into urea that can be eliminated through the kidneys. L-Arginine is an important intermediate in this process.
• What does pharmaceutical-grade L-Arginine mean?
  NOW identifies its L-Arginine ingredient as pharmaceutical grade, indicating that the ingredient is produced according to defined quality and purity specifications. The product remains a dietary supplement rather than an FDA-approved prescription medication.
• What is free-form L-Arginine?
  Free-form L-Arginine is supplied as an individual amino acid rather than bound within an intact dietary protein. It does not require the same initial breakdown of protein structures during digestion.
• How should I take NOW L-Arginine 500 mg?
  NOW recommends taking 2 capsules twice daily as needed, between meals or at bedtime, with at least 8 oz of water or juice.
• Should I take L-Arginine with food?
  The manufacturer's directions recommend taking the capsules between meals or at bedtime rather than specifically with meals.
• Why should I take L-Arginine with water or juice?
  NOW specifically directs users to consume the capsules with at least 8 oz of water or juice to facilitate absorption.
• How much L-Arginine is provided by four capsules?
  Four capsules provide 2,000 mg (2 g) of L-Arginine, equivalent to the manufacturer's suggested two servings per day.
• Can I combine L-Arginine with L-Citrulline?
  L-Arginine and L-Citrulline participate in related metabolic pathways, and some sports nutrition products combine them. However, appropriate supplementation depends on individual needs, health status, and medication use. Consult a healthcare professional before combining nitric oxide-related supplements.
• Can L-Arginine affect blood pressure?
  L-Arginine participates in nitric oxide production, which influences blood vessel relaxation. It may interact with blood-pressure medications or other agents affecting vascular function. NOW specifically advises consulting a physician when taking antihypertensive medications.
• Who should avoid NOW L-Arginine?
  The product label advises against use by pregnant or nursing women and people who have experienced myocardial infarction or have established coronary artery disease. It also advises people with glaucoma or herpes simplex to avoid use unless otherwise prescribed by a physician. Additional medical cautions apply.
• Can people with kidney disease take L-Arginine?
  NOW specifically advises consulting a physician before use if you have renal disease. Individual suitability depends on kidney function and other medical considerations.
• Is NOW L-Arginine vegan?
  Yes. The product is identified as vegetarian and vegan and uses a cellulose-based capsule rather than animal-derived gelatin.
• Is NOW L-Arginine Non-GMO?
  Yes. The product carries NOW's Non-GMO labeling.
• Is NOW L-Arginine gluten-free?
  The product is not manufactured with wheat or gluten ingredients. However, it is produced in a GMP facility that also processes ingredients containing certain allergens.
• Is NOW L-Arginine Halal and Kosher?
  The supplied product information identifies both Halal and Triangle K Kosher status.
• Does NOW L-Arginine contain caffeine or stimulants?
  No caffeine or conventional stimulant ingredients are listed. The active ingredient is free-form L-Arginine.
• Is NOW L-Arginine manufactured under GMP standards?
  Yes. NOW identifies GMP quality assurance and Intertek GMP certification covering manufacturing and quality-control procedures.
• What are the other ingredients?
  Hypromellose (cellulose capsule), stearic acid from a vegetable source, and silicon dioxide.
• How many capsules are in one bottle?
  Each bottle contains 100 vegetable capsules.
• How many servings are in each bottle?
  The Supplement Facts panel identifies 50 servings per container, based on a 2-capsule serving size.
• How long does one bottle last?
  At the manufacturer's suggested twice-daily intake of 4 capsules total, one 100-capsule bottle provides 25 days of supplementation.
• Does NOW L-Arginine need refrigeration?
  No refrigeration requirement is stated. NOW recommends storing the product in a cool, dry place after opening.