Peer-led team learning is a socially mediated pedagogy where trained peer leaders, students who have completed a course, return to lead students in groups within a targeted course. The effect of peer-led team learning to improve student success in chemistry has been extensively documented but it is unclear if it is just as effective at facilitating retention of knowledge across time. This paper describes two studies designed to examine this possibility, each focusing on the impact of peer-led team learning in second-semester general chemistry on students' long-term knowledge of chemical equilibrium. The first study measured student knowledge at three time points for one year following enrollment in general chemistry. The second study measured student knowledge while enrolled in analytical chemistry. Both studies used a repeated measures design and found no demonstrable effect of pedagogy on the long-term retention of knowledge. This finding indicates that concepts students hold in first-year chemistry remain long-standing throughout their undergraduate training, conceptual understanding of equilibrium shows ample room for improvement across both pedagogies, and peer-led team learning supports knowledge retention comparable to didactic instruction.