Four studies examined the willingness of young, healthy individuals to take drugs intended to enhance their own social, emotional, and cognitive traits. We found that people were much more reluctant to enhance traits believed to be more fundamental to self‐identity (e.g., social comfort) than traits considered less fundamental to self‐identity (e.g., concentration ability). Moral acceptability of a trait enhancement strongly predicted people’s desire to legalize the enhancement but not their willingness to take the enhancement. Ad taglines that framed enhancements as enabling rather than enhancing the fundamental self increased people’s interest in a fundamental trait enhancement and eliminated the preference for less fundamental over more fundamental trait enhancements.