This article details an attempt to understand better how first-year doctoral students construct persuasive arguments in academic writing by exploring the patterns of boosters in drafts of doctoral research proposals. Eight Malaysian first-year ESL doctoral students produced 43 drafts of doctoral research proposals across four areas of study in education during their first year of doctoral studies. These drafts were analysed by coding the various linguistic items used to persuade readers of a text, and the analysis was based on Hyland’s (2005) model of metadiscourse. Results show that the (i) overall frequency of booster markers used is relatively low (n=158), reinforcing the argument that first-year doctoral students lack understanding about the interaction between booster markers and the context in a more complicated discussion in academic writing such as the doctoral research proposal. Then, the (ii) further analysis of booster marker sub-categories indicates that Malaysian first-year doctoral students struggle to make appropriate booster markers with different meanings and strengths in academic writing when used in context. Therefore, our study suggests that direct and explicit teaching of using various booster markers categories should be implemented in postgraduate writing courses to heightened the students’ perceptiveness regarding semantic features associated with creating convincing arguments in academic writing.