Jarrow Formulas^® Arginine-Citrulline Sustain™ is a synergistic combination of two amino acids to support nitric oxide (NO) production, blood flow and cardiovascular health.* L-Citrulline largely converts to L-Arginine, increasing circulating and blood vessel levels of L-Arginine for NO production.* Arginine-Citrulline Sustain™ provides these amino acids to the body over an 8 hour period.*