Louise, the mastermind behind this A-list service , normally delivers it to her famous clientele inside her New York atelier, but she refers to it in more polite terms as the EGF (epidermal growth factor) facial. The growth factor used in this case is foreskin — harvested and extracted from the stem cells of a Korean newborn's circumcised foreskin. It's potent stuff that encourages skin cells to turn over rapidly, so it's used for its brightening, tightening, and wound-healing properties, but not everyone is sold. Anti-circumcision activists , for one, are not fans, and most experts, though they acknowledge the immediate skin benefits, say there is just not enough research yet on the long-term safety of prolonged use of growth factors.