DL-5-Hydroxytryptophan is used primarily as a precursor in the synthesis of serotonin, a neurotransmitter that regulates mood, sleep, and appetite. It is commonly used in dietary supplements aimed at supporting mental well-being, particularly for managing symptoms of depression, anxiety, and insomnia. Due to its role in increasing serotonin levels, it has also been explored for use in weight management, as serotonin can influence satiety and reduce carbohydrate cravings. Additionally, it is used in research settings to study neurotransmitter pathways and neurochemical imbalances. Some clinical applications include its use in treating fibromyalgia and preventing migraine headaches, although evidence varies in strength across these uses.