It makes up the primary agents in connective tissue, collagen and elastin.  Collagen and elastin keep our skin, joints, hair and nails strong and vital.  Dental health is also dependent on threonine because it helps to form tooth enamel.  Threonine is a part of the immune proteins called antibodies.  Several types of these molecules are released by white blood cells to flag cells and tissue so that the appropriate immune response can occur.  For example, the destruction of a cell infected with a virus or a cell growing uncontrollably (cancer).

Threonine can be supplemented to help with the following health concerns: low immune function, depression, muscle weakness, fatty liver, dental cavities, poor tooth development, arthritis and skin damage.

Threonine is usually supplemented as L-threonine.  L-threonine is found in capsules.  It is best absorbed when it is taken between meals.  If you take an individual amino acid supplement for longer than one month, add an amino acid complex to the protocol to prevent the deficiency of other amino acids.

Vegetarians are more likely to be deficient in threonine than meat eaters.  Low threonine levels cause irritability.