L-Arginine 500mg 250 Capsules | Free-Form Pharmaceutical Grade, Now Foods

Now Foods L-Arginine delivers 500mg of free-form, pharmaceutical-grade (USP) L-arginine per capsule — the body's primary nitric oxide precursor — in a flexible 250-capsule format that allows dosing from 500mg to 3,000mg daily depending on individual needs. 250 capsules providing 125 servings at 2 capsules. GMP quality assured. Now Foods, family owned since 1968.

Why you need it

L-arginine is a conditionally essential amino acid — meaning the body can synthesise it, but not always in sufficient quantities during periods of high demand such as intense exercise, illness, injury, or ageing. It plays several critical roles in human physiology.

Nitric oxide production: L-arginine is the primary substrate from which the body synthesises nitric oxide (NO) via the enzyme nitric oxide synthase. Nitric oxide is a potent vasodilator — it signals the smooth muscle cells lining blood vessels to relax, widening the vessels and improving blood flow. This makes L-arginine central to cardiovascular health, healthy blood pressure regulation, erectile function, and exercise performance, where improved circulation enhances oxygen and nutrient delivery to working muscles.

Urea cycle and detoxification: L-arginine plays a key role in the urea cycle — the metabolic pathway by which the liver converts toxic ammonia (a byproduct of protein metabolism) into urea for safe excretion. Adequate arginine is essential for this detoxification process to function efficiently.

DNA synthesis and protein production: Arginine is involved in DNA synthesis and serves as a building block for protein production, supporting tissue repair, immune function, and growth hormone secretion.

This product uses free-form L-arginine (USP pharmaceutical grade) — the most bioavailable form, absorbed directly without requiring conversion from a salt form such as L-arginine HCl.

Key benefits

• Nitric oxide precursor — primary substrate for NO synthesis, supporting vasodilation and healthy blood flow
• Cardiovascular support — supports healthy blood pressure and vascular function via NO-mediated vasodilation
• Exercise performance — improved circulation supports oxygen and nutrient delivery to working muscles
• Urea cycle support — essential for ammonia detoxification and healthy liver function
• Flexible dosing — 500mg per capsule allows precise adjustment from 500mg to 3,000mg daily
• Free-form USP grade — maximum bioavailability, pharmaceutical purity standard

Formula

500mg free-form L-arginine (USP pharmaceutical grade) per capsule. Gelatin capsule. Not vegan — contains bovine gelatin. Contains no sugar, salt, starch, yeast, wheat, gluten, corn, soy, milk, egg, shellfish, or preservatives.

Supplement Facts

Serving size: 2 capsules | Servings per container: 125
L-Arginine (free-form, USP): 1,000mg (1g) per 2-capsule serving | 500mg per capsule
*Daily Value not established.

Suggested use

Take 2 capsules 1 to 3 times daily as needed. For best absorption, take between meals or at bedtime with a carbohydrate drink — insulin released in response to carbohydrates enhances amino acid uptake into cells. The 500mg-per-capsule format allows flexible dose adjustment.

Other ingredients

Gelatin (capsule), magnesium stearate (vegetable source), silica. Contains no sugar, salt, starch, yeast, wheat, gluten, corn, soy, milk, egg, shellfish, or preservatives. Not vegan — contains gelatin capsule.

Why trust this product

Now Foods has been a family-owned leader in quality nutritional supplements since 1968, with GMP quality assurance and USP pharmaceutical-grade ingredients. The 250-capsule format offers outstanding value for long-term supplementation, with the flexibility of 500mg per capsule for precise dose management. Also available in a double-strength 1,000mg tablet format.

Important

⚠️ Important contraindications — do not use this product if you:

• Have had a myocardial infarction (heart attack) or have established coronary artery disease — arginine supplementation is contraindicated in these conditions
• Have glaucoma — unless specifically prescribed by a physician
• Have a history of herpes simplex — arginine can promote HSV replication; avoid unless prescribed

For adults only. Consult your healthcare practitioner before use if pregnant, breastfeeding, taking medication, or managing any medical condition. Keep out of reach of children. Store in a cool, dry place.