Saw palmetto is a plant that is typically marketed to men (its normally under the men's section in health stores) but that is just because they are not acknowledging its other benefits. It is used by men to prevent or help with prostate cancer and health, it does this by blocking the conversion of testosterone (or something fo that nature.. if you want to know specifically i will gladly find you the right info) so that is why it is also able to block the male hormones in our bodies and prevent acne from coming up. The only downside I have heard with saw palmetto is weight gain for some but I personally have not experienced this (only clearer skin

)
I neither gained wore nor lost it while I was taking Diane-35 and hve not heard how it affects women's weights in general. It is I believe one of the strongest BCPs and is definitely meant for women who severe problems with excess androgens (male hormones) which causes our bad acne.
Hope I helped best wishes
