What's the difference between D-Methionine and DL-methionine?

Methionine is a critical amino acid in the production of creatine. Creatine plays second string to the needs such as carnitine for the heart muscles. DL-methionine in the right mixture creates sort of starvation. Nothing is left for creatine production but the D-isomer, eating more introduces more D-isomer into the equation.

L-methionine is the only assimilable isomer that does not require an unnatural conversion, over excretion, or, execrative metabolism. D-methionine may become involved preliminarily in some simple metabolic processes. It may be integrated accidentally into proteins, in effect denaturing those proteins to varying degrees. Exactly how D-methionine is handled by mammalian systems is not of scientific importance because naturally it would never happen.