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Optimum Nutrition Serious Mass Side Effects

author image Brian Willett
Brian Willett began writing in 2005. He has been published in the "Buffalo News," the "Daytona Times" and "Natural Muscle Magazine." Willett also writes for and He is an American Council on Exercise-certified personal trainer and earned a Bachelor of Arts in journalism from the University of North Carolina.
Optimum Nutrition Serious Mass Side Effects
Optimum Nutrition Serious Mass may help you gain lean muscle mass.

Optimum Nutrition Serious Mass is a high-calorie, high-protein supplement intended to promote increases in lean muscle mass and weight. While Optimum Nutrition Serious Mass may help you gain muscle when used in conjunction with a workout program, it may also trigger unpleasant side effects. This product provides 50 g of protein and more than 250 g of carbohydrates per serving. As with any supplement, you should consult your doctor before using Optimum Nutrition Serious Mass.

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Fat Gain

Optimum Nutrition's Serious Mass contains 1,250 calories per serving, which represents 62.5 percent of the average daily suggested intake of 2,000 calories. One pound of fat contains 3,500 calories, so if you ate at your maintenance level of calories and added one serving of Optimum Nutrition Serious Mass to your regular diet, you would gain 1 lb. within three days. However, you can counteract the excess calories by working out, which burns calories and promotes muscle gain.

Liver Problems

Each serving of Optimum Nutrition Serious Mass provides the entire daily recommended intake of vitamin A. So if you consume other foods rich in vitamin A, such as carrots, spinach and kale, you may be at risk for an overdose of vitamin A, which may cause liver problems. Serious Mass contains 50 g of protein per serving, which is also an entire day's worth; registered dietitian Katherine Zeratsky notes too much protein may cause or exacerbate existing liver problems.

Kidney Damage

Optimum Nutrition Serious Mass contains creatine, an ingredient that is used in many supplements to promote muscle and strength gain. If you are using Serious Mass with other supplements that contain creatine, you may be at risk for kidney damage, as the University of Maryland Medical Center notes this is a side effect of creatine. Registered dietitian Zeratsky explains that high protein intake may also be associated with kidney damage.

Impaired Workout Recovery

One benefit of exercise such as resistance training is that it improves insulin sensitivity, which helps your body use insulin more efficiently and decreases the risk of fat gain. However, a study published in the May 2009 issue of "Proceedings of the National Academy of Sciences" found that consuming vitamin C and vitamin E in conjunction with workouts inhibits improvements in insulin sensitivity promoted by exercise. Each serving of Serious Mass contains 100 percent of the recommended daily intake of both vitamins. This may hamper your workout recovery.

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