Firstly I would just like to say that everytime I order from iHerb my goods arrive in less than 5 days. I live in Australia, so that is excellent service. Have been using L-citrulline for about 3 months now. I am 50 years old and pre-hypertensive. 5 months ago I was put on 2 anti-depressants and my blood pressure soared to 160/95 and my resting pulse rate increased from 54 to about 72, even though I circuit train 3 to 4 times a week. My blood pressure medication was only bringing my figures down to about 140/86. After incorporating l-citrulline into my training regime I have steadily seen my resting blood pressure come down to about 122/78 and pulse rate back down to about 58. My recovering from training is a lot quicker, plus i need less break between my reps, which means I can train harder. I dont use it after 2 pm so that it does not interfere with my blood pressure medication which i take in the evening. One of the common side effects of anti depressants is that they are not very good for your sex life. Well after being on l-citrulline for a couple of months, there has been a significant improvement in that department! It works for me. I take 3 capsules mid morning and then 3 half an hour before training. My advice to anyone that wants to increase their cardiac fitness is to give it a try for a couple of months and of course eat a healthy diet as well.