Heather Phares of AllMusic wrote that "Fabulous Muscles" "might be the best expression of Xiu Xiu's unrepentantly original music; even if the world that the band creates isn't necessarily one you'd want to visit all the time, it remains fascinating." "Pitchfork"s Matt LeMay also praised the album, writing, "Though there are many notable high points to "Fabulous Muscles", its overwhelming consistency is what cements its place as Xiu Xiu's finest. The album does not contain a single hiccup or yawn-- no extraneous noise, no potentially offputting histrionics, no throwaways and no dull moments." The album also received a "Best New Music" designation in the review. Adrien Begrand of "PopMatters" praised it as "more focused and direct" than "A Promise".