The more compact magazine, measuring 232x172mm, is the result of six months of reader research, although it follows a well-trodden path for glossy magazines shrinking, which also includes Bliss and Cosmopolitan.
The new issue, which features Paris Hilton on the cover, will include a separate 28-page magazine called LadMag, which is described as "all about boys... but for girls".
Although Hachette has vowed that Sugar will appeal to readers on the basis of its editorial innovation rather than by giving away cover-mounted gifts, Hachette is not risking low sales for the first issue and will include a lip and cheek tint, as well as offers for seven free gifts for readers, including a mobile ringtone and a diamante bracelet.
Sugar is the market-leading magazine in its category, but it reported a decline in circulation of 3.5% in the last set of published ABCs, selling an average of 285,082 copies an issue.
Julie Harris, general manager of the women's group at Hachette Filipacchi UK, said: "As a result of talking to readers, advertisers and retailers, we are convinced that the new, compact Sugar is the perfect size for today's teenage girl.
"Our focus is on increasing value through editorial innovation rather than giving away yet another cover gift, and we believe that LadMag will drive loyalty of purchase over time."
Its relaunch comes after Hachette Filipacchi suspended publication of another of its teen girl titles, ElleGirl, in October last year as a result of falling sales.
Publishing companies have found it increasingly difficult to hang on to teenage readers, or the iPod generation as they sometimes referred to, having to compete with the internet, computer games and paid-for mobile phone content.
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