Nothing, I remember my husband bought this for me just after the New Year last year. At that time, I said I wanted to exercise and asked my husband to help me find it online. In fact, my husband doesn't agree with me to eat those things that hurt my health, and let me go to the gym with him to exercise, but I don't want to exercise and I'm afraid of becoming a woman. I've really used this, and it works. You can try!