If you are natural, you must build muscle the old-fashioned way. Grimek, Hackenschmidt, Klein, Eifferman, Apollon, Travis, Farbotnik, and others earned their muscle and respect. The drug using stars of today get no respect from me. The second part of the absolute rule is good nutrition. I mean food, not powders, pills, and promises.
Most food supplements are a waste of money.
Two cans will give enough complete protein for anyone, in addition to one's regular well-balanced diet. Drink plenty of water and eat 5 to 9 fruits and vegetables per day. If you are trying to gain weight, throw in a few nutritious snacks as well. Today's drug-using stars don't eat broiled skinless chicken salad, a carrot, and water, as the megahype magazine pictures show. Go to the fast food restaurants in Santa Monica, and you will see many of them.