Optygen: Increases the body's ability to adapt to high levels of physical stress. Improves the body's utilization of oxygen, increases VO2 Max and anaerobic threshold while reducing lactic acid. OptygenHP: provides 1,000mg Beta-Alanine per serving. Beta-Alanine increases muscular endurance, boosts strength, improves exercise capacity and delays muscular fatique. HP has 5% rosavin-Rhodiola and is 67% more active than the 3% Rhodiola found in the original Optygen formula