The idea that the degree of infringement public health interventions have on individual rights should be proportional to the degree of expected benefits has emerged as an influential principle in public health ethics and policy. While proportionality makes sense in theory, it may be difficult to implement in practice, due to the inherent conflict between individual rights and the common good underlying the principle. To apply the proportionality principle to a decision of policy, one must still find a reasonable way of balancing these competing values in light of the available options and empirical evidence. In this article, I consider how the proportionality principle applies to the regulation of dietary supplements and examine some critiques of the current oversight system. I argue that it may be difficult maintain proportional oversight because the risks of dietary supplements vary considerably. Strengthening the regulations may therefore promote an appropriate level of regulation in some cases but lead to overregulation in others.