Weight-gain supplements, such as whey protein and creatine, can have several negative side effects. These include dehydration, bloating, fatigue, kidney damage and liver damage, according to WebMD. Therefore, experts recommend consuming weight-gain supplements with caution.
Whey protein can be extracted from milk and taken as a weight-gaining supplement. While used to build muscle and improve athletic performance, it is linked to several undesired side effects. These side effects include bloating, increased bowel movement, cramps, reduced appetite and fatigue, notes WebMD. A healthy person should have no more than 20-to-30 grams of whey protein each day, states Mayo Clinic.
An additional weight-gaining supplement is creatine. This supplement is naturally found in fish and meat but can also be extracted and sold as a powder, explains WebMD. One of the most common side effects of creatine consumption is dehydration. Creatine causes the muscles to use more water; these fluids need to be regularly replaced when a person takes this supplement. In addition, creatine can adversely impact kidney and liver function. More serious side effects include heart failure and stroke, and the risk of these side effects increases when creatine is taken with caffeine. Consume no more than the recommended daily dosage of 15-to-25 grams for the first week, recommends Nutrition Express.