Nothing, Regular Food And Cobitex Vitamin Tablet. I Want To

Nothing, regular food and Cobitex vitamin tablet. I want to gain weight. I am a 30 year old male. I want to increase my testosterone level. I am not getting hair on my chest and I am thin. I eat lot of food and maintain my calories for past 2 years but no change same 175 cms and 60 Kg for last 2 years. I want to gain weight and I need hair on chest. To my finding low testosterone is the cause for this. If I am wrong correct me.