Just wait until you turn 40. It's very difficult for some people to gain weight, even if you eat enough, and even if you lift hard. How tall are you? How much

Just wait until you turn 40. It's very difficult for some people to gain weight, even if you eat enough, and even if you lift hard. How tall are you? How much do you weigh? How much do you want to gain? Who/what do you want to look like? While you certainly can add muscle, you should be cautioned against trying any program to significantly change your basic build. If you're naturally thin, then you can be muscular, but you'll still be generally thin, and you probably can't ever be a tank. Being a tank is really more about your genetics ( bone structure, shape of your chest, overall length of your muscles ) than working out. Not saying it's your goal to be a tank, just trying to provide some realistic counsel.