Is anyone taking arginine? Is this also just "expensive urine"?

I've been taking the arginine Kim Jong-kook uses, along with swimming and weight training.
Recently, perhaps due to the effects of squats, I feel like my blood circulation is improving in the early morning hours; could arginine be playing a role in this?
I've heard that liquid supplements are just "expensive urine"—does arginine also get mostly excreted through urine?