Objectives Using nationally representative data for adults of age 25 years and older from four waves of the National Health and Nutrition Examination Survey (NHANES), collected from 2003 through 2010, this study examines differences in individual health markers used to calculate allostatic load, with particular attention given to stratification by race/ethnicity and educational level. Methods Factor analysis with maximum likelihood estimation was used. Fisher's r to z transformation test was used to determine whether or not observed differences in factor loadings were statistically significant. Results The findings reveal the unidimensionality of the concept of allostatic load and the underlying differences in associations between individual biomarkers and summary measures of allostatic load. Additionally, metabolic processes tend to be the most important predictor of allostatic load for all adults; however, inflammatory measures are more important in determining allostatic load scores for non‐Hispanic blacks compared to non‐Hispanic whites and for adults with less than a college education compared to adults with some college or a college degree. Conclusions These findings highlight the continued importance of studying the concept of “weathering” or allostatic load at the population level and need to better understand how population groups facing exclusion from economic, social, and political power may internalize this position which may cause early health deterioration and ultimate mortality chance through different expression of health insults and premature aging. Am. J. Hum. Biol. 28:627–635, 2016. © 2016 Wiley Periodicals, Inc.