Methionine is an essential amino acid found in protein food sources such as meat and dairy. Your body cannot make methionine, so you must get it from food or supplements. It is important for many functions in the body, including building new proteins, making DNA, and normal tissue growth and repair. There are two types of methionine: L-methionine (which is naturally occurring and usually found in supplements) and D-methionine. Each contains the same chemical makeup, but the molecules are mirror images. A mixture of the two is called DL-methionine. There is no suggested dose for methionine supplements, but you should get about 14 milligrams (mg) daily per kilogram (Kg) of bodyweight.  Used for the treatment of acetaminophen overdose, may help improve liver damage and may support cancer prevention. Other uses include nourishing hair, skin and nails, slowing down cell aging, protecting cells from pollutants, assisting with absorption of other nutrients and aiding in the detoxification of heavy metals.  Side effects
Nausea Vomiting Drowsiness Irritability