Sam Baker has left Cosmopolitan to edit Red, a magazine with less than half its circulation.
Cosmopolitan, which is 40 next year, has an ABC figure of 461,610, while Red recorded a circulation of 219,689 in the last six-month period.
But the latter is the market leading older glossy in the increasingly strong 30-something market, and recorded a tenth consecutive year-on-year increase from July to December last year.
Baker has been Cosmo editor for the past two years, but worked on Red prior to its launch almost 10 years ago. She has also worked on New Woman, Chat, and Take a Break, and relaunched Emap's Just Seventeen as J-17.
She spent five years as editor of Company, before resigning to write Fashion Victim, her first novel.
Baker said: "I'm incredibly pleased to be leading a magazine that has so clearly defined a new market, and am looking forward to building on its already strong position."
Baker succeeds Trish Halpin, who is moving to InStyle as editor. She is expected to remain at Cosmo until a replacement is found.