Vitamin A deficiency has been a trigger of impotence in some men. Vitamin A! "Vitamin A deficiency has been the cause of impotence in some men," says Elson Haas, M.D., Director of the Preventive Healthcare Middle. More frequently than not Erectile Dysfunction is temporary. Muira Puama for occasion assists a guy have harder erections and increased libido because it is regarded as a nerve stimulant.