The word ergosterols is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 14
Highest Scoring Words With Friends™ Plays In The Letters ergosterols
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Seven Letter Word Alert: (28 words)
egoless, glosser, grosser, loosest, looters, osselet, ostlers, regloss, regosol, regress, regrets, reroots, resoles, resorts, resters, restore, retools, rooster, rooters, roselet, rosters, sorrels, sorters, stereos, sterols, stooges, toeless, toolers