i have not used evening primrose in a long time but when i did use it i used it with SP and Maca before incorporating it with the others i noticed little to nothing, and while using it i didnt notice any signs of low t taking place (libido drop, difficulty with erections, sluggish energy, etc..) i did notice that my skin was considerably softer and over about 3 months using it my back side did seem to be filled out more, lost 7 pounds but pants were getting much tighter. Quit using it due to finding PM and Natureday but i did seem to have physical difference when using it with SP