Plasma Testosterone Levels before, during and after Chronic Marihuana Smoking

To test the relation between chronic marihuana use and testosterone levels, we studied 27 men, 21 to 26 years of age. Plasma testosterone was measured daily before, during, and after a 21-day period of marihuana use. The mean pre-use testosterone level of 12 casual users (who smoked an average of 54 marihuana cigarettes during the 21-day use period) was 988±93 ng per 100 ml (±S.E.M.), and that of 15 heavy users, who smoked an average of 119 cigarettes, was 1115±69 ng per 100 ml. No statistically significant changes in plasma testosterone levels were observed during and after the smoking period as compared with the pre-smoking base-line levels. These data do not corroborate an association between chronic marihuana use and decreased plasma testosterone. (N Engl J Med 291:1051–1055, 1974)