L-Arginine - Sustained Release: A Formula for Nitric Oxide and Blood Flow Thorne's L-Arginine - Sustained Release, formerly known as Perfusia-SR®, is a high-quality amino acid supplement designed to support cardiovascular health and optimal blood flow. L-arginine is the body's primary precursor to nitric oxide, a crucial molecule that helps blood vessels relax and dilate. This advanced formula utilizes a proprietary time-release matrix (Time-Sorb®) to release L-arginine gradually, ensuring a sustained benefit for circulation and vascular health throughout the day. How It Works: The Time-Sorb® ...