In a controlled trial, 5-HTP (300 mg per day) was shown to be effective in reducing many symptoms of fibromyalgia, including pain, morning stiffness, sleep disturbances, and anxiety.
For depression, 300 mg per day is often effective, though much of the research used 5-HTP in combination with drugs or was uncontrolled. For insomnia, a single 100-mg nighttime dose of 5-HTP was sufficient to improve the duration and depth of sleep in one placebo-controlled trial. For migraine headaches, amounts ranging from 400–600 mg per day have been shown to be effective at reducing the frequency and severity of attacks in most clinical trials. For tension headaches, 100 mg of 5-HTP taken three times per day led to a significant decrease in consumption of pain-relievers, but no significant change in headache duration or intensity.
Appetite reduction and weight loss (averaging 11 pounds in 12 weeks) has occurred with amounts of 600–900 mg daily. In another clinical trial, 750 mg per day has been shown to be effective at decreasing carbohydrate and fat intake, and promoting weight loss.