Appeton gain weight safe and effective?

Why do you want to? If you are a thin person and just want to gain weight, what you want is muscle not fat. The only weigh to increase muscle tone and/or mass is with weight (resistance) training. Otherwise the weight you gain will be fat. Not good! So be delighted that you are not a part of the obesity epidemic and go a gym and get toned muscles. If there is another reason that you wish to gain weight, ask again.