synthol
n.— «Invented in the mid-1990s by a German bodybuilder named Chris Clark, synthol is a thick oil that is usually injected directly into the “belly” of a muscle to literally pump it up—albeit temporarily. Competitive bodybuilders originally used synthol and other products like it, known collectively as site enhancement oils, to even out minor asymmetries in muscle size and shape.» —“Buying Massive Muscles” by Dan Childs WPVI-TV (Philadelphia, Pennsylvania) May 16, 2007. (source: Double-Tongued Dictionary)