Studies have found that aspartame can over-stimulate or interfere with nerve endings, increase muscle tension and lead to migraine. Aspartame exists in diet coke, diet soda, sugar-free chewing gum, ice cream, multivitamins and many patented drugs. Therefore, people who are allergic to sugar substitutes will have a headache as long as they drink a low-sugar soda.
However, aspartame is a sweetener allowed to be used in food in China. Therefore, as long as it is not excessive, it will not do much harm to the human body.