Which nutrients are a valuable resource in trying to build muscle?

Healthy diet: When you're trying to muscle up, try to eat one gram of protein (preferably lean) for each pound you weigh, or 2.2 grams for each kg. A snack of maybe 20 grams of protein after a workout is helpful. Avoid greasy, sugary and salty foods as much as is convenient. Creatine isn't a nutrient but will help you gain mass. I am very glad you're undertaking fitness activities -- make it a lifetime habit.