Early adulthood is often characterized by a phase of excess mortality. It is not clear whether this temporary increase in the risk of death occurs because of biological or contextual forces, nor whether this threat concerns all individuals of the same cohort. Age-specific mortality differentials from 10 to 34 years of age are calculated using a unique dataset that includes all individuals living in Switzerland born between 1975 and 1979. Certain risk factors act with variable intensity and follow patterns similar to the hump observed in the overall age-specific mortality risk. The results suggest that socioeconomic mortality differentials partly shape the hump. The division of the cohort into multiple subpopulations representing various levels of vulnerability shows that although a minority of Swiss youth experience a phase of temporary excess mortality, this is not the case for all groups of individuals. Overall, the results indicate that a favourable social context offsets the stress associated with the transition to adulthood and helps avoid the phase of heightened risk of death during this period of life.