There is limited research to back up these claims.
Some women take L-tryptophan supplements to try to ease mood swings due to premenstrual syndrome (PMS), also called premenstrual dysphoric disorder (PMDD). The theory is that these conditions may be linked to a problem with serotonin processing in the body, and that L-tryptophan could help that. However, there is little evidence to show this really works.
Early research in people hints that L-tryptophan supplements may be helpful for:
The amount of L-tryptophan in these foods is small compared to supplements.
What are the risks of taking L-tryptophan?
L-tryptophan has been linked to a dangerous, even deadly condition called eosinophilia-myalgia syndrome (EMS). The FDA recalled tryptophan supplements in 1989 after tens of thousands of people who took them became sick, and some died. EMS causes sudden and severe muscle pain, nerve damage, skin changes, and other debilitating symptoms. Doctors saw a lot fewer people with EMS after the ban. Some research suggests the sickness was due to contaminants that got into the supplements during manufacturing in a factory in Japan.