Lysine is a normal amino acid. It may or may not survive the
gastrointestinal tract of the mother. Even if it does, there is no
reason to believe it would increase the amount in the milk. Even if it
did, it would likely not survive digestion in the gastrointestinal tract
of the baby. Even if it did, there is no evidence this would be harmful
for the baby if he did absorb it.
Jack Newman, MD, FRCPC