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BACKGROUND: We studied the effect of a single dose of a formulation of a methanolic extract of Hypericum perforatum (HP), also known as St. John's wort, on plasma concentrations of growth hormone (GH), prolactin (PRL), and cortisol (CORT) in 12 healthy male volunteers. METHODS: Subjects received 9 tablets of the finished product Jarsin 300 and placebo in a double-blind, balanced-order, cross-over design. RESULTS: Following HP relative to placebo, there was a significant increase in plasma GH and a significant decrease in plasma PRL. Plasma CORT levels were unchanged. CONCLUSIONS: Taken together with data from animal experimental studies, the findings suggest that this dose of HP may increase some aspects of brain dopamine function in humans.


Journal article


Biol Psychiatry

Publication Date





581 - 584


Adult, Anti-Bacterial Agents, Antidepressive Agents, Bridged Bicyclo Compounds, Cross-Over Studies, Double-Blind Method, Ericales, Humans, Hydrocortisone, Male, Middle Aged, Perylene, Phloroglucinol, Plants, Medicinal, Prolactin, Somatostatin, Terpenes