Arginine has many benefits and depending on what are planning or achieving you should change doses.
For erection the minimum dose a day must be of 6 grams and on empty stomach. If you want really good effects just before sex take at least 10 grams 1 hour before sex.
Also arginine might help more erections on some and less on others, depending on why is your erection not so hard.
For example if your problem is from smoking or lack of exercise then arginine is definitely your thing, but you should really take it everyday 6 grams.
Arginine is totally harmless, but like everything in this world, don’t abuse it, and if doesn’t work after one month with the right dosage, don’t go crazy taking more, just try a different thing.
First time I took arginine was not on a program, I was just at a friend house and he showed me this drinkable arginine, with 2.8 grams each piece, I took just one, and on the next day I couldn’t stop thinking about sex.