Sex offenders are sometimes offered or required to undergo pharmacological interventions intended to diminish their sex drive (anti-libidinal interventions or ALIs). In this paper, we argue that much of the debate regarding the moral permissibility of ALIs has been founded on an inaccurate assumption regarding their intended purpose—namely, that ALIs are intended solely to realise medical purposes, not correctional goals. This assumption has made it plausible to assert that ALIs may only permissibly be administered to offenders with their valid consent, in line with the approach taken to most other interventions with a medical aim. However, we argue that, contrary to this assumption, the state's intention in relation to at least some ALIs is, at least in part, to achieve correctional objectives. We evaluate two legal regimes for ALI provision—section 645 of the California Penal Code and the mental health regime in England and Wales. In each case, we identify the state's implicit purpose in imposing ALIs and argue that the Californian and English regimes both serve as counterexamples to the view that ALIs are intended solely for medical purposes. While the moral implications of our argument are not straightforward, it raises the question whether consent is required for permissible imposition of ALIs, and more generally, whether the moral permissibility of crime-preventing interventions using medical means should be assessed against the standards of medical ethics or against those of criminal justice ethics.