A couple females have used ketotifen but most have not. T-3 does make a difference in fat burning when using clen. Not using t-3 or ketotifen with clen will not keep clen from combating cortisol levels-hence the reason women experience muscle growth with this product. My theory is that women as a whole produce more cortisol than men which would be one factor out of many as to why they gain body fat easier and gain muscle slower