Purpose of review <p>Insulin restriction is commonly studied as a form of disordered eating, but people may restrict insulin for many reasons. This systematic review examined how insulin restriction has been conceptualized and measured, and its associated predictors and outcomes.</p> Recent findings <p>Forty-seven unique articles measured non-specified insulin restriction (IR), insulin restriction specifically for weight control (IRWC), or both. Eight studies used non-specified measures to examine insulin restriction for a specific purpose. IR was more prevalent than IRWC, but both occurred equally among men and women across ages. Higher negative emotions were associated with both constructs, while lower self-management behaviors were examined and associated only with IR; both constructs were associated with higher HbA1c. When measured simultaneously, IR and IRWC were not correlated.</p> Summary <p>There may be subtypes of insulin restriction. Future research should develop measures to assess and examine distinct subtypes, and translate findings into effective interventions for this dangerous behavior.</p>