Advice on this please...?

Hello. I am 16 years old 17 in 2 weeks. Im considering buying this in tablet form at 500mg. I'm going to be taking a carbohydrate shake with this also and flaxseed oil because I am trying to gain weight as I have a high metabolism Is this safe to take? And will it help me to get bigger and also I heard it helps increase penis size? But I'm taking it for muscle growth.... Please don't answer with silly replies.. Many thanks in advance... :)