The speculated low ebb for Bauer's global powerhouse means FHM has lost more than 50,000 sales copies, or a third of its UK and Ireland newsstand sales, since its last official ABC average between July and December 2009.
The March issue of the title, featuring Abbey Clancy as its cover star, represented the third time the title had been overhauled in recent months.
Poor sales are blighting the entire men's lifestyle sector which is struggling to compete with digital rivals.
FHM's circulation drop comes despite a revamp and changes to the title in the last two years, designed to lure back readers. They have included a complete new layout introduced by the design guru Jeremy Leslie and the internal FHM team.
Editor Colin Kennedy introduced his first design overhaul last year in a bid to ditch the title's laddish reputation.
According to the latest Audit Bureau of Circulation (ABCs) figures, between July and December 2009, FHM's circulation showed optimistic signs despite a struggling men's lifestyle sector.
Although overall circulation fell 15.2% on the year to 231,223 copies, it fell just 1.6% over the six-month period, indicating that the title's revamp was bearing fruit.
The accolade of the biggest-selling men's lifestyle magazine in the UK, a position once held by FHM, is now held by Natmag Rodale's Men's Health.
Bauer declined to comment.