*T&C Apply: while stock lasts. Not avialble in conjunction with any other offer.
Optimum Nutrition Serious Mass is the ultimate high calorie weight gaining formula for rapid muscle growth. Serious Mass has a huge 1250 calories and 50g protein per serve. This is significantly more than just about any other weight gaining formula on the market. If you are a hard gainer and have tried other weight gaining products with no success then you need to get Serious Mass. Serious Mass will ensure that you are supplying your body with all the nutrition that it needs to grow muscle mass as fast as possible.