Nancy Mahon doesn’t consider herself a glamour girl, but she believes in the power of lipstick — Viva Glam shades 5 and 6 in particular. Mahon is a senior vice president of MAC Cosmetics and executive director of the MAC AIDS fund, which last year donated million to programs in 57 countries, including South Africa, the Caribbean and the United States. The non-profit program makes MAC the third-largest corporate donor to AIDS-related causes, and is funded entirely by sales of MAC’s Viva Glam lip products. Unlike other business philanthropy models, 100% of the suggested retail price tag for each lipstick goes to the AIDS fund — even retailers are expected to forgo their margin, Mahon noted at a recent Wharton Leadership Lecture. She told students that it is important for a company not only to be good at business, but also to treat employees well, conduct business responsibly and behave as a good global citizen. “It’s one thing to sell lipstick,” Mahon said one associate told her.…