Now Sports Arginine & Citrulline Powder

NOW Sports Arginine & Citrulline Powder combines two complementary amino acids in a balanced 1:1 ratio to support nitric oxide production, protein metabolism, healthy circulation, and normal muscle function. Each level teaspoon delivers 1,500 mg of free-form L-Arginine and 1,500 mg of free-form L-Citrulline, providing 3 grams of amino acids in a pure, easy-to-mix powder designed for active individuals and fitness enthusiasts.* Arginine and Citrulline work together in important metabolic pathways involved in nitric oxide synthesis, nitrogen balance, and protein utilization. Both participate in the urea cycle, where the body converts ammonia produced during amino acid metabolism into urea for elimination. Citrulline can also be converted into Arginine within the body, supporting the availability of this important nitric oxide precursor. NOW Sports Arginine & Citrulline contains no other ingredients and is vegan, Non-GMO, keto-friendly, and Informed Sport tested. With approximately 113 servings per 12 oz container, this straightforward amino acid formula provides convenient support for an active lifestyle.* Expand All Highlights 3,000 mg total amino acids per serving 1,500 mg L-Arginine (Free-Form) 1,500 mg L-Citrulline (Free-Form) Balanced 1:1 Arginine-to-Citrulline ratio Supports normal nitric oxide production* Supports healthy circulation and vascular function* Important for protein metabolism and utilization* Supports normal muscle tissue maintenance* Both amino acids participate in the urea cycle* Supports normal nitrogen metabolism and ammonia processing* L-Citrulline can be converted into L-Arginine in the body* Convenient, easy-to-mix amino acid powder Contains no other ingredients No added sugars, flavors, colors, or sweeteners 15 calories per serving Unflavored for convenient mixing with beverages Vegan Keto-friendly Non-GMO Informed Sport tested Steroid tested GMP Quality Assured Halal and Kosher (Triangle K) Approximately 113 servings per container Net weight: 12 oz (340 g) Key Benefits Nitric Oxide Support: L-Arginine serves as a precursor to nitric oxide (NO), a signaling molecule involved in normal blood vessel relaxation and vascular function. L-Citrulline can be converted into L-Arginine, providing a complementary pathway for supporting Arginine availability.* Healthy Circulation: Nitric oxide participates in regulating vascular tone and normal blood flow. Together, Arginine and Citrulline provide amino acids involved in these physiological processes.* Protein Metabolism: Both amino acids participate in pathways associated with protein metabolism and utilization, supporting normal cellular processes and tissue maintenance.* Muscle Tissue Maintenance: L-Arginine contributes to normal protein synthesis, while both amino acids participate in nitrogen metabolism, important processes involved in maintaining healthy muscle tissue.* Nitrogen Balance: Arginine and Citrulline are intermediates in the urea cycle, where the body converts ammonia generated during protein metabolism into urea for excretion.* Complementary Amino Acid Pathways: Citrulline can be converted into Arginine through normal metabolic processes, helping support the body's supply of an important nitric oxide precursor.* Exercise Nutrition: Arginine and Citrulline are commonly used in sports nutrition formulas because of their roles in vascular signaling and amino acid metabolism. Research on improvements in exercise performance and muscle pumps has produced mixed results.* Pure Amino Acid Supplementation: Contains only L-Arginine and L-Citrulline without stimulants, proprietary blends, artificial flavoring, or added sweeteners. Flexible Powder Format: Can be mixed into water or another beverage, making it convenient to incorporate into an existing nutrition or training routine. Key Ingredients L-Arginine (Free-Form) — 1,500 mg: A conditionally essential amino acid involved in nitric oxide synthesis, protein metabolism, and the urea cycle. L-Arginine serves as a substrate for nitric oxide synthase, the enzyme responsible for producing nitric oxide. It also participates in the conversion of ammonia into urea and contributes to normal protein production and cellular function.* L-Citrulline (Free-Form) — 1,500 mg: A nonessential amino acid that participates in the urea cycle and can be converted into L-Arginine within the body. Citrulline supplementation has been studied for its potential to increase circulating Arginine availability and support nitric oxide-related pathways involved in vascular function.* 1:1 Arginine & Citrulline Combination — 3,000 mg: Each level teaspoon contains equal amounts of both free-form amino acids, providing a straightforward combination that supports normal nitrogen metabolism, protein utilization, and pathways involved in nitric oxide production.* How It Works NOW Sports Arginine & Citrulline Powder combines two amino acids that participate in complementary metabolic pathways. L-Arginine is a conditionally essential amino acid that serves as a precursor to nitric oxide (NO), a signaling molecule produced by nitric oxide synthase enzymes. Nitric oxide helps regulate vascular tone by signaling smooth muscle within blood vessel walls to relax, contributing to normal circulation and vascular function. L-Citrulline supports this process through a different pathway: after absorption, Citrulline can be converted into Arginine, primarily through metabolic processes involving the kidneys and other tissues. This relationship makes Citrulline an important component of the body's normal Arginine metabolism. Both amino acids are also intermediates in the urea cycle, which converts potentially harmful ammonia generated during protein and amino acid breakdown into urea for elimination. Arginine additionally participates in protein synthesis and other metabolic processes involved in maintaining healthy tissues. By providing 1,500 mg of each free-form amino acid per serving, NOW Sports offers a balanced combination designed to support these normal physiological functions. While Arginine and Citrulline have been investigated for potential exercise-performance and circulation benefits, clinical results depend on dosage and individual physiology, and specific improvements have not been established for this finished product.* What Makes It Different Balanced 1:1 Formula: Provides equal amounts of L-Arginine and L-Citrulline rather than relying on a single nitric oxide-related amino acid. 3 g Amino Acids: Delivers 1.5 g Arginine and 1.5 g Citrulline in each level teaspoon. Free-Form Amino Acids: Both ingredients are supplied as individual amino acids rather than bound within intact dietary proteins. Complementary Nitric Oxide Pathways: Arginine is directly used in nitric oxide synthesis, while Citrulline can be converted into Arginine through normal metabolic processes. Protein Metabolism Support: Combines amino acids that participate in protein utilization and nitrogen metabolism. Urea Cycle Support: Both ingredients are important intermediates in the body's normal ammonia-processing pathway. Two-Ingredient Formula: The Supplement Facts panel lists L-Arginine and L-Citrulline with no other ingredients. No Added Stimulants: Contains no caffeine or other conventional stimulant ingredients. Unflavored Powder: Can be added to water, smoothies, sports drinks, or other beverages without added flavoring ingredients. Keto-Friendly: Identified by NOW Sports as suitable for ketogenic lifestyles. Vegan: Contains no declared animal-derived ingredients. Non-GMO: Carries NOW's Non-GMO product designation. Informed Sport Tested: Displays the Informed Sport mark, indicating participation in a sports supplement testing program for substances prohibited in sport. Steroid Tested: Product packaging identifies steroid testing as part of its athlete-focused quality assurance. GMP Quality Assured: Manufactured under NOW's established supplement manufacturing and quality-control standards. Halal & Kosher: Displays Halal and Triangle K Kosher designations. Made & Quality Tested in the USA: Produced with globally sourced ingredients under NOW's quality assurance program. 113 Servings: Each 12 oz container provides approximately 113 one-teaspoon servings. Who It’s For Strength-training and resistance-training athletes interested in amino acid supplementation Fitness enthusiasts researching nitric oxide precursor formulas Active adults looking to support normal protein metabolism* Individuals interested in the role of Arginine and Citrulline in vascular function* People seeking nutritional support for normal muscle tissue maintenance* Athletes who prefer stimulant-free sports nutrition supplements Those looking for a balanced combination of Arginine and Citrulline People interested in amino acids involved in the urea cycle and nitrogen metabolism* Adults who prefer free-form amino acid powders rather than capsules Individuals who want a simple formula without proprietary blends People seeking a powder without added sweeteners, artificial colors, or flavors Vegan supplement users Those following ketogenic nutrition plans Athletes who value Informed Sport testing and manufacturing quality controls Adults looking for a larger container with approximately 113 servings People who have reviewed potential cardiovascular, kidney-related, and medication precautions with a healthcare professional Suggested Use Mix 1 level teaspoon (approximately 3 g) in 8 oz of water or another beverage. Take twice daily as needed, according to the manufacturer's directions. Preferably take on an empty stomach. Mix thoroughly before consuming. Each teaspoon provides 1,500 mg L-Arginine and 1,500 mg L-Citrulline. Two servings provide a combined daily intake of 3 g L-Arginine and 3 g L-Citrulline. Store in a cool, dry, dark place after opening. Natural color variation may occur. This product is sold by weight, not volume. Do not eat the enclosed freshness packet. Warnings: For adults only. Consult a physician if pregnant or nursing, taking medication (especially antihypertensives, nitrates, or other heart medications), or if you have a medical condition (especially herpes, kidney impairment, and/or glaucoma). Keep out of reach of children. Other Ingredients None. This product contains only L-Arginine (Free-Form) and L-Citrulline (Free-Form). It is not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut, or sesame ingredients. Produced in a GMP facility that also processes other ingredients containing these allergens. FAQs What is NOW Sports Arginine & Citrulline Powder? It is a two-amino-acid supplement providing equal amounts of free-form L-Arginine and L-Citrulline to support normal protein metabolism, nitrogen processing, muscle tissue maintenance, and nitric oxide-related physiological pathways.* How much Arginine and Citrulline are in each serving? Each level teaspoon provides 1,500 mg of L-Arginine and 1,500 mg of L-Citrulline, for a combined 3,000 mg of amino acids. What is the serving size? The Supplement Facts panel lists 1 level teaspoon, approximately 3 g, as one serving. What does a 1:1 Arginine-to-Citrulline ratio mean? It means that the formula contains equal quantities of the two amino acids. Each serving provides 1.5 g L-Arginine and 1.5 g L-Citrulline. What is L-Arginine? L-Arginine is a conditionally essential amino acid involved in nitric oxide production, protein synthesis, and nitrogen metabolism. It is also an important intermediate in the urea cycle. What is L-Citrulline? L-Citrulline is a nonessential amino acid that participates in the urea cycle and can be converted into L-Arginine within the body. It has been investigated for its potential to support Arginine availability and nitric oxide-related pathways.* Why combine L-Arginine and L-Citrulline? The two amino acids participate in complementary pathways. L-Arginine serves as a direct precursor to nitric oxide, while L-Citrulline can be converted into L-Arginine, supporting the body's normal Arginine metabolism.* What is nitric oxide? Nitric oxide (NO) is a signaling molecule that helps regulate blood vessel relaxation, vascular tone, and normal blood flow. How do Arginine and Citrulline support nitric oxide production? L-Arginine is used by nitric oxide synthase enzymes to produce nitric oxide. L-Citrulline can be converted into L-Arginine, providing an additional metabolic pathway associated with maintaining Arginine availability.* Does NOW Sports Arginine & Citrulline support circulation? The amino acids participate in pathways involved in normal vascular function and nitric oxide signaling. However, supplementation does not guarantee increased circulation, and measurable effects depend on dose and individual circumstances.* Can Arginine and Citrulline improve workout muscle pumps? Both amino acids are used in sports nutrition because of their relationships with nitric oxide production. Some studies have investigated their effects on exercise blood flow and muscle pumps, but results have been inconsistent, and benefits from this specific formula are not established. Does this supplement improve athletic performance? Research involving Arginine and Citrulline has explored exercise capacity, muscular endurance, and vascular responses. Findings vary by dose, formulation, and study population. This product should not be expected to produce guaranteed performance improvements. How do these amino acids support protein metabolism? Arginine is used in normal protein synthesis, while both Arginine and Citrulline participate in metabolic pathways involving nitrogen processing and amino acid utilization.* Do Arginine and Citrulline support muscle tissue maintenance? Both amino acids participate in physiological processes involved in protein and nitrogen metabolism. Maintaining muscle tissue also requires adequate overall protein intake, appropriate nutrition, and physical activity.* What is the urea cycle? The urea cycle is a metabolic process that converts ammonia produced during amino acid metabolism into urea, allowing the body to eliminate nitrogen-containing waste. Arginine and Citrulline are important intermediates in this pathway. What is the difference between free-form amino acids and protein powder? Free-form amino acids are supplied as individual amino acid molecules, whereas protein powders contain larger protein structures that must be digested into peptides and amino acids. This product is not a complete protein supplement. Is Arginine & Citrulline Powder a pre-workout supplement? It can be incorporated into a workout nutrition routine, and NOW Sports markets it within its sports nutrition range. However, it does not contain caffeine or a conventional multi-ingredient pre-workout blend. Does it contain caffeine? No. The Supplement Facts list only L-Arginine and L-Citrulline, with no caffeine or other stimulant ingredients. How should I take NOW Sports Arginine & Citrulline Powder? Mix 1 level teaspoon into 8 oz of water or another beverage, twice daily as needed, preferably on an empty stomach. Should I take it on an empty stomach? Yes. NOW recommends taking the powder preferably on an empty stomach. Can I mix it with a smoothie or sports drink? Yes. The manufacturer's directions allow mixing it with water or another beverage. How much Arginine and Citrulline do two servings provide? Two servings provide 3,000 mg L-Arginine and 3,000 mg L-Citrulline, for a combined total of 6 g of amino acids. Does it contain any other ingredients? No. The label explicitly states Other Ingredients: None. Is NOW Sports Arginine & Citrulline vegan? Yes. The product displays a vegan designation and contains only the two amino acids. Is the product keto-friendly? Yes. The front label identifies it as keto-friendly. Is it Non-GMO? Yes. The product carries NOW's Non-GMO designation. Is it gluten-free? The product is not manufactured with wheat or gluten ingredients. However, NOW states that it is produced in a GMP facility that also processes ingredients containing common allergens. What does Informed Sport testing mean? Informed Sport is a sports supplement testing and certification program designed to help reduce the risk of contamination with substances prohibited in sport. The supplied NOW Sports packaging displays the Informed Sport designation. Is NOW Sports Arginine & Citrulline steroid tested? Yes. The supplied packaging displays steroid-tested and Informed Sport quality marks. Is the product manufactured under GMP standards? Yes. NOW identifies GMP Quality Assured manufacturing and associated quality-control procedures. Is NOW Sports Arginine & Citrulline Halal and Kosher? The supplied packaging displays Halal and Triangle K Kosher designations. Can I take this supplement with blood-pressure medications? Consult your physician before use. The manufacturer's warning specifically identifies antihypertensive medications, nitrates, and other heart medications because of potential interactions involving vascular and blood-pressure regulation. Who should consult a healthcare professional before using it? NOW advises medical consultation for individuals who are pregnant or nursing, taking medications, or managing medical conditions, particularly herpes, kidney impairment, or glaucoma. How many calories are in each serving? The Supplement Facts panel lists 15 calories per level teaspoon. How many servings are in each container? Each 12 oz container provides approximately 113 servings. How long does one container last? At the manufacturer's suggested twice-daily use, approximately 113 servings provide about 56 days of supplementation. Does this product require refrigeration? No refrigeration requirement is stated. NOW recommends storing the product in a cool, dry, dark place after opening. Expand All