Just a heads-up.
If you google "F4X", at the top of the auto-suggest terms, is "F4X Scam". There are several in the list with Scam in the title. I was just googling it to see if I could find further info on the workout, such as a video of a consumer showing what is in the workout.
Curiosity got the better of me and I clicked on one of the Google hits with "F4X SCAM" in the title. Twice. Both times, and I'm going to guess that similar titles will turn out to be the same, WERE LINKS TO THEIR ORDER PAGE, OR A "REVIEW" OF THE WORKOUT (positive) with a LINK TO ORDER!! The review did use the word Scam several times, in sentences such as, "F4X a Scam? You decide, after you look in the mirror and see your self from ten years ago [reverse aging]". Also, simply: "F4X Scam.... F4X Workout.". Something like that. Also, don't forget about Pay-Per-Click, which if they get any benefit from that, then all the complaints pages I alone have read, being links back to their main site, could have generated income for them. They needn't even have a viable product!
Reminds me of Amway!
You make your own decision (there is a money-back-guarantee, if I'm not mistaken), but for me the dishonest way they've gone about marketing leaves a bad taste in my mouth. And by the way, there are literally hundreds of YouTube Workouts online you can follow for free.
Note: I have no affiliation with F4X company, its owners, the workout, or sales/advertising of it.