NEW YORK—Kyowa Hakko received a patent for the amino acid combination of L-Citrulline and L-Arginine, protecting its use in formulations used to rapidly and effectively increase blood L-Arginine levels.

L-Arginine is an amino acid critical to the production of nitric oxide (NO) in the body. NO helps regulate and improve blood circulation. L-Citrulline is a major precursor to L-Arginine and has been shown in other studies to increase L-Arginine levels, and thus improve NO production.

“We measured blood L- Arginine levels and Nitric Oxide levels 40 minutes and 60 minutes after amino acids administration," said Ryusuke Nakagiri, senior director of strategic science at Kyowa Hakko USA. “At both time points, the combination of L-Citrulline and L-Arginine had a better effect than the single amino acids."

A related animal study published in November in Biochemical and Biophysical Research Communications showed L-Citrulline plus L-Arginine supplementation caused a more rapid increase in plasma L-Arginine levels and marked enhancement of NO bioavailability, including plasma cGMP (Cyclic guanosine monophosphate) concentrations, than with dosage with the single amino acids.

Research released last year also links L-Citrulline and heart health.