Griffonia Simplicifolia enhances the activity of serotonin, a hormone produced by the brain that is involved in mood, sleep and appetite. Decreased levels of this neurotransmitter has been associated with depression, insomnia, obsessive/compulsive disorders as well as eating disorders leading to obesity, or the reverse/bulimia.
In a study employing positron-emission tomography(PET) scanning, eight healthy volunteers and six people diagnosed with major depression received infusions of radio labelled 5-HTP. The researchers found that significantly less 5-HTP crossed the blood-brain barrier into the brains of the depressed subjects than into the brains of the normal controls1. A significant reduction in anxiety was observed on three different scales designed to measure anxiety2. In a study of 20 people with panic disorders, several experienced a feeling of "relief" after receiving 5-HTP. A group of Italian researchers reported that 20 obese patients taking 5-HTP (900 mg/day) lost a significant amount of weight, had less carbohydrate intake, and consistently became sated earlier than a similar group taking a placebo3.