Typical symptoms inlcude headache, a burning sensation along the back of the neck, chest tightness or pain, nausea, sweating, and a sensation of facial pressure or infraorbital pressure. Pins and needles or tingling may be experienced in the limbs or face and head. Reactions are thought to occur only if MSG is eaten on an empty stomach. Onset occurs in 15 to25 minutes. In adults, a threshold level of 1.5 to 3 grams is required before symptoms occur.
Females are more affected.
Young children experience shudder attacks or shivering, and older children get migraine attacks. A recent study has ascribed these symptoms to histamine in foods. As these symptoms differ from that classically caused by histamine, further definitive studies are required. These are uncommon but may occur following MSG ingestion. Foods containing MSG Chinese food highly seasoned restaurant meals, spices such as Aromat , cheeses, tomatoes, mushrooms, instant soups, gravies.