This study from Jesuit Social Services quantifies the unique influence of young men’s personal endorsement of the 'Man Box' masculinity pillars on different areas of their lives including mental health, substance use, relationships and violent/bullying behaviour. This is the second stage of this research, and involved surveying a large sample of 1,000 young men aged 18-30. The findings show how endorsement of hyper-masculine norms can effect young men's behaviours and life outcomes, and makes several recommendations for future research and policy in this area.