The influence of a passion flower extract on free testosterone in healthy men: a two part investigation involving younger and older men

Abstract

Plant-based nutrients have been studied for their potential impact on testosterone production in men. We investigated the influence of a novel passion flower extract on free testosterone in healthy men. In part one of this study, 18 younger men (35.9 ± 1.6 years) were assigned to consume placebo tablets or tablets containing a passion flower extract, in a random order, double-blind, cross-over design. The treatment period for each condition was 15 days, with a two-week washout period between conditions. Blood and saliva were collected both in the morning and the evening on days 1, 8, and 15—both before and one hour following ingestion of the assigned condition. In part two of this study, seven older men (55.9 ± 2.7 years) were assigned to consume the passion flower extract or placebo tablets in a random order, double-blind, cross-over design. The treatment period was the same as for part one and but only saliva was collected in the morning on days 1, 3, 8, and 15. All subjects completed a questionnaire on the morning of each test day to determine their subjective feelings associated with the condition treatment. Passion flower extract did not appear to influence free testosterone or subjective feelings in younger men. However, free salivary testosterone was increased an average of 13% in older men. In addition, an increase of 17% was noted from day 1 to day 15 for perceived energy level, while an increase of 9% was noted for libido when older men used the extract. A novel passion flower extract does not influence testosterone concentrations or subjective feelings in younger men but may have an influence on these outcomes in selected older men. It is possible that the treatment may be more effective when delivered to those with low baseline testosterone values.