A mass gainer is a supplement that helps you gain weight and build muscle. It's packed with calories, protein, carbs, and sometimes added vitamins to support muscle growth. Mass gainers can be an easy way to get the extra nutrients if you're struggling to eat enough food to meet your calorie needs. They are great for people who want to bulk up, athletes who need more energy, or anyone with a fast metabolism. Mix it with water or milk and drink it after workouts or between meals to fuel your body. Mass gainers help you reach your fitness goals faster by giving your body the extra boost it needs.