Have you ever thought about being a personal trainer or a fitness influencer or running your own gym or CrossFit Box? That new career could be closer than you think—and you could very well help transform hundreds or thousands of lives and help reverse the staggering adult obesity rates in the U.S.

Make no mistake, the road to becoming a trainer is not designed to be easy, and isn’t as simple as taking a test. Becoming a quality trainer takes years of education and hands-on experience—you’ll have to dig deep for this career. But starting the lifelong journey to change people’s lives as a trainer, coach, gym owner, or nutritionist all begins with the first step. Yet with so many programs to choose from—and so many debatably less-legitimate certifying organizations crowding the great ones—how do you pick your ideal program?

We sat down with the directors of certification and elite trainers from each of the top fitness certification organizations to pinpoint the strengths of each one. No two are exactly alike, but by peeking behind the curtain of their curricula and missions, this guide may help you find your perfect fit to start a new career ASAP.