Debates on moral enhancement focus legitimate attention on the questions of whether it is possible and/or what could count as a moral enhancement given deep ethical disagreement. I argue here that moral enhancements might not even be rational to consider—from the perspective of the agent. At issue is the assessment of whether the enhancement is truly reliable. Since we assess reliable belief forming processes by their outputs, whether they are true, an agent who is entertaining a putative moral enhancement faces (...) a trilemma. If she already believes the promised outputs of the enhancement, the enhancement is obsolete. If she does not believe the promised outputs, it would be irrational from her current perspective to undertake the “enhancement.” If she is uncertain, she has no reason for thinking that the enhancement truly augments her moral beliefs. On any option, the agent has no reason for taking a putative moral enhancement. (shrink)