Overview
L-arginine is a semi-essential amino acid involved in protein synthesis, nitric oxide (NO) production, immune function, and cardiovascular regulation. It serves as the primary substrate for nitric oxide synthase (NOS), promoting vasodilation and endothelial function, which underpins its potential benefits in cardiovascular health, exercise performance, and pregnancy-related complications such as preeclampsia [2][3][7]. Supplementation may improve insulin sensitivity, reduce cardiometabolic risk, and support gut integrity, particularly in conditions involving impaired endogenous synthesis, such as after intestinal resection or in inflammatory bowel disease (IBD) [2][7]. While endogenous production typically meets needs in healthy adults, dietary or supplemental arginine may be beneficial in specific clinical contexts, including metabolic dysfunction, pregnancy, and critical illness.
Dosage Guide
Recommended Daily Allowance
For generally healthy individuals
Therapeutic Doses
For treatment of specific conditions
Upper Intake Limit
Maximum safe daily intake
30 g— Up to 30 g/day well-tolerated in 90-day trial; higher doses may cause GI distress [1]
Special Forms
Alternative forms for specific needs
Superior to arginine for raising plasma arginine levels, especially after intestinal resection or in poor absorbers
Common in sports supplements; may enhance NO production and nutrient delivery
Clinical Notes
- High doses (>10 g) may cause gastrointestinal side effects (diarrhea, bloating, abdominal pain)
- Avoid high-dose supplementation in active herpes virus infections (arginine may promote viral replication)
- Use caution in severe liver or kidney disease due to role in urea and nitrogen metabolism
- Monitor blood pressure in hypotensive individuals; arginine's vasodilatory effects may potentiate medications
- Citrulline may be preferred over arginine for improving arginine bioavailability in gastrointestinal disorders
Research
Oral L-arginine at 15–30 g/day was well-tolerated in overweight/obese adults over 90 days, with no serious adverse events reported.
Arginine metabolism is disrupted in inflammatory bowel disease; supplementation may support intestinal repair and immune modulation during remission.
L-arginine supplementation during pregnancy may improve fetal growth and reduce preeclampsia risk, with emerging potential for pharmacogenomic dosing.
In ruminants, endogenous arginine synthesis meets most requirements, but dietary supply becomes critical under metabolic stress.
Intestinal resection impairs citrulline and arginine production; citrulline may be more effective than arginine for restoring arginine levels.
L-arginine administration influences hormone release (e.g., insulin, growth hormone) and may alter exercise metabolism via nitric oxide pathways.
Low-dose, slow-release arginine may be more effective for improving endothelial function and insulin sensitivity in individuals with metabolic dysfunction.
Oral arginine alters multiple metabolic pathways in rats, but enzyme deficiencies (e.g., arginase, NOS) may affect response and safety.
