PGX^® does not contain any stimulants that increase heart rate or leave you feeling anxious or jittery. In the clinical trials of PGX^®, some people reported gas or bloating, both of which are commonly noticed when increasing the amount of fibre in your diet. When these symptoms were noticed, they tended to last 3-7 days, but can be easily limited – by gradually working up to the recommended dose, and by drinking lots of water with your PGX^®.