What are the nutrilite bio c side effects? is advisable to take it?

Overall safe: As it's really just a different "delivery mechanism" to get vitamin C into your system. And vitamin C is fairly well tolerated, assuming you don't take very high doses which might set you up for kidney stones, or create problems if you have abnormal red blood cells or iron storage issues. But in general, consider trying to increase your consumption of fruit to get natural sources of vitamin C.