A weight gainer is a dietary supplement often used by people who have difficulty gaining weight. This product functions as an appetite booster, meaning that it helps increase natural appetite, making bulkers more inclined to take in enough nutrition necessary for weight gain. 

A weight gainer is a dietary supplement intended primarily for individuals who have difficulty gaining weight or muscle mass. It can be particularly useful for: Persons with a fast metabolism, athletes and bodybuilders, and persons who have difficulty eating large amounts of food.

It is highly recommended to exercise while using the weight gainer, especially if your goal is to build muscle mass and not just gain weight.

Results when using weight gainers can vary greatly among individuals. While some individuals notice changes quickly, such as an increase in appetite, which can often be seen within three days, others may take longer to see visible results. It is important to remember that everyone's body responds uniquely.

If your appetite decreases after you stop using the weight gainer, but you continue to eat healthy, balanced meals that meet your daily caloric needs, you are unlikely to lose weight.