I am in week 8 of a cycle, taking mK2866 and Gw. I started Mk at the recommended 12.5 dose for 2 weeks, I am female, I then bumped to 25, as recommended. About 5 days into the 25 my nipples got super sensitive! I backed the MK back to 12.5 and it went away. 12.5 works just great for me.