The key difference between Yaz and Yasmin is the amount of estradiol (a type of estrogen) they have. Yaz has less and Yasmin has more. The other difference is the number of inactive pills they have. Yaz has 24 active + 4 inactive (sugar) pills. Yasmin has 21 active + 7 inactive pills. The point of fewer inactive pills is to make your monthly withdrawal bleed less bothersome with fewer cramps, and to help reduce acne. There may be impacts on the protocol related to the hormone levels, but I don't know. The upshot for people on the protocol, since we "stack" our pills and don't do the inactive week, is that with Yaz you get 3 extra active pills in each pack and that means you can go just a tiny bit longer between refills.