It may be creatine, which is an amino acid that’s supposed to help ATP transfer, or energy movement, in the brain and muscle tissue. Not to be confused with protein powder, which is a supplement taken to help with muscle recovery and the building blocks of growth. Supplementing with creatine is supposed to increase your workout potential (ei. more energy expended), so that you have greater muscle growth in a shorter period of time. Not to be confused with steroids, lol.
Jury is still out when this is discussed in fitness and weight lifting communities. :) Many lifters swear by it, but I can’t help but wonder if it’s the placebo affect making already fit lifters try harder and become more defined. I’ve never played with it myself.
Honestly? I doubt you would notice a difference unless you’re already a hardcore competetive bodybuilder (um, naturally I hope, no steroids?) and you’re already doing everything else correctly in the first place. Most people, even those who’ve only been seriously involved bodybuilding or weight lifting for a couple years, could get better results from more rest, more water, and proper nutrition outside of the gym to supplement what we do inside of it.