Restricting one's access to temptations (precommitment) facilitates the achievement of long-term goals. The sophisticated impulsiveness model of precommitment posits that impulsive agents who are aware that they are impulsive should show the strongest preference for precommitment. Empirically however, two central predictions of this theoretical notion remained untested: whether impulsiveness causally drives the demand for precommitment and whether the willingness to precommit depends on metacognitive awareness of one's impulsiveness. Here, we tested these predictions in three independent experiments. Participants performed a delay discounting task in which they could precommit to larger-later rewards. The results of Experiment 1 provide causal evidence that reducing impulse control capacities increases precommitment demand. Moreover, Experiments 2 and 3 support the hypothesis that metacognitive awareness of one's impulsiveness moderates the relationship between impulsiveness and precommitment. Together, our data put the sophisticated impulsiveness model of precommitment on strong empirical foundations.