This paper contributes to an on-going exchange in political theory on the normative legitimacy of expert bodies. It focuses on epistemic worries about the expertisation of politics, and uses the Nordic system of advisory commissions as an empirical case. Epistemic concerns are often underplayed by those who defend an increasing role of experts in policy-making, while those who have epistemic worries often tend to overstate them and debunk expertise. We present ten epistemic worries, of which some are of an epistemological nature, while others are related to failures and biases. These worries must not be overstated, but no doubt point to real problems which have to be handled through the design of expert bodies and institutions of science advice. We introduce three groups of mechanisms that are likely to contribute to remedying the problems of expertise and discuss what they imply for the design of a system of public advisory commissions.