This study aimed to evaluate the motivations and concerns related to preprint use among Brazilian health researchers. A mixed-methods online survey of all 1,596 holders of CNPq Research Productivity Grants in seven health fields was conducted in 2025. The questionnaire was adapted from a survey of bioRxiv authors, translated into Portuguese, and pilot-tested. Closed-ended responses were analyzed descriptively, and free-text responses were grouped by similarity. Overall, 178 researchers accessed the survey (11.2%), and 143 answered items on preprints and were included in the final analysis (9.0% effective response rate). The mean age was 55.9 years, and 88.0% were affiliated with public institutions. Regarding corresponding-author publications over the previous five years, 62.2% of respondents had deposited no preprints, while 37.8% had deposited at least one. Among preprints users, 79.2% agreed that deposition was freely decided by the authors. The main motivations were rapid sharing of findings (69.8%) and obtaining feedback (49.1%). Few reported benefits in terms of citations (17.3%) or online dissemination (16.9%). Among those who had not deposited preprints, the main reason was not wanting to deposit them (57.6%), followed by being unaware of the option (35.3%). Of the 22 free-text responses, 19 reflected an informed decision not to deposit, most commonly because peer review was considered necessary before public dissemination. Preprint use was limited mainly by a lack of intention to deposit rather than a lack of awareness. Faster dissemination and feedback were the main motivations for using preprints.