Sweet Orange Oil Used on the Skin for Stress and Depression: A study was performed with 39 volunteers using breathing masks to prevent the inhalation of the aroma of sweet orange. The essential oil was diluted and applied to the skin. The study revealed that the transdermal (skin) absorption of sweet orange essential oil led to a significant decrease in autonomic nervous system activity (reduced pulse rate, decreased breathing rate) and led to changes in subjective mood; indeed, sweet orange improved mood and energy!!
Hongratanaworakit T and Buchbauer, G. Autonomic and emotional responses after transdermal absorption of sweet orange oil in humans: placebo controlled trial. International Journal of Essential Oil Therapeutics (2007) 1,29-34.