LINUS PAULING INSTITUTE

T The body makes Proline (amino acid) from Glutamic acid, and deficiency is rare in healthy individuals with a healthy diet . People with traumatic injury may want to supplement. People with traumatic injury may want to supplement. People with pain caused by insufficent cartilage or collagen formation could benefit from extra Proline in their diet as well. Meat, dairy eggs, possess proline, vegatarians with a low protein diet need proline.

L. Pauling Institute ( source)