Daily supplementation with arginine can reduce blood pressure in people with healthy blood pressure and people with hypertension (high blood pressure).[1] Evidence also supports the use of arginine to help improve birth outcomes in pregnant women who have conditions like hypertension and preeclampsia, or who have a history of poor pregnancy outcomes. The improved outcomes include a reduced risk of small for gestational age infants[2] and a reduced risk of intrauterine growth restriction of the baby.[3] Arginine can also improve maternal outcomes by reducing the risk of preeclampsia in the pregnant mother.[4][5][6] Additionally, arginine can reduce blood triglycerides,[7][8] particularly in people older than 50 or in people with metabolic syndrome or type 2 diabetes.[7]
In men with erectile dysfunction, daily supplementation with arginine can alleviate symptoms.[9] Furthermore, the combination of arginine with phosphodiesterase type 5 inhibitors (PDE5Is), like Viagra, improves sexual function in men with erectile dysfunction more than treatment with PDE5Is alone.[10]
Evidence also shows that daily supplementation with arginine might increase VO2max, but the magnitude of improvement is negligible and unlikely to be clinically meaningful.[11] Furthermore, most studies find no beneficial effect of arginine on exercise performance.[12] It is only when highly-varied types of exercise (aerobic, anaerobic, resistance, etc.) and performance outcomes (time-to-exhaustion, time-trials, sprint time, 1-rep-max, reps-to-failure, etc.) are inappropriately pooled that meta-analyses find a performance benefit from arginine.[12]