Clean Gainer by RivalusRivalus Clean Gainer Its no secret that to gain muscle mass you have to eat in a surplus protein intake is crucial when muscle building, and fats and carbohydrates are essential to help support that process as well. But a lot of mass gainer products out there are full of confusing ingredients that may leave you scratching your head. Enter Rivalus Clean Gainer, chock full of high quality ingredients to support you to be your best during your training,