BackgroundGrowing numbers of students now seek mental health support from their higher education providers. In response, a number of universities have invested in non-clinical well-being services, but there have been few evaluations of these. This research addresses a critical gap in the existing literature.AimsThis study examined the impact of introducing non-clinical well-being advisers on student mental health and help-seeking behaviour at a large UK university.MethodSurvey data collected pre–post service introduction in 2018 (n = 5562) and 2019 (n = 2637) measured prevalence of depression (Patient Health Questionnaire-9), anxiety (Generalised Anxiety Disorder-7), and low mental well-being (Warwick–Edinburgh Mental Wellbeing Scale), alongside student support-seeking behaviour. Logistic regression models investigated changes in outcome measures. Administrative data (2014–2020) were used to investigate corresponding trends in antidepressant prescribing at the onsite health service, student counselling referrals and course withdrawal rates.ResultsAdjusted models suggested reductions in students’ levels of anxiety (odds ratio 0.86, 95% CI 0.77–0.96) and low well-being (odds ratio 0.84, 95% CI 0.75–0.94) in 2019, but not depression symptoms (odds ratio 1.05, 95% CI 0.93–1.17). Statistical evidence showed reduced student counselling referrals, with antidepressant prescribing and course withdrawal rates levelling off. Student perception of the availability and accessibility of university support improved.ConclusionsOur findings suggest a non-clinical well-being service model may improve student perception of support, influence overall levels of anxiety and low well-being, and reduce clinical need. The current study was only able to examine changes over the short term, and a longer follow-up is needed.