Optimum Nutrition Serious Mass Protein Powder, Chocolate Peanut Butter 6LB | Weight Gainer Protein Powder, Mass Gainer with Whey Protein, Creatine, Glutamine, BCAAs, Vitamins & Minerals, Easy Mixing

Amazon reviewers say this Serious Mass flavor is generally valued for taste and weight-gain support, with mixed opinions on protein content, mixability, and calories. Some reviewers praise the chocolate peanut butter flavor as tasty and good value, while others mention the tub size and the need for careful mixing or extra water.

On Walmart and Macy’s, customers describe it as effective for gaining mass, with repeated praise for the flavor and overall results. Reviewers also note that it can be very filling and sometimes too sweet, but many still recommend it for bulking.

Reddit discussion about Serious Mass is more focused on whether it helps with gaining weight, with users reporting noticeable gains after use. Fitness review sites and supplement retailers are broadly positive, often highlighting the high calorie content and easy mixing, though some caution that it may be overkill unless the goal is rapid weight gain.