Betaine or Trimethylglycine provides:
Three methyl groups. These can be used to create SAMe from Homocysteine. SAMe then acts as a cofactor for COMT which gets rid of excess norepinephrine. Norepinephrine is the primary signal that keeps you awake.
Glycine. Glycine is an inhibitory (i.e. sedating) neurotransmitter like GABA. Glycine also unlike GABA improves memory by preloading the Glutamate Receptor for activation. Glycine alone can be used to improve sleep.
SAMe also is a cofactor in producing certain neurotransmitters including serotonin. Serotonin is a calming neurotransmitter - helping reduce norepinephrine signaling. Serotonin can also be converted to Melatonin, which helps sleep.
RE: o