Yes you should take glycine on an empty stomach before bed or before you have breakfast.
The glycine is best taken before bed on an empty stomach for best absorbtion.
If you're taking clozapine you should avoid taking glycine as it can cause some bad interactions with each other.
Glycine is an amino acid which is a building block for protein.
However it is not considered an “essential amino acid” because the body can make it from other chemicals.
A typical diet contains about 2 grams of glycine daily and the primary sources are protein-rich foods including meat, fish, dairy, and legumes.
Some side effects of taking Glycine are gastrointestinal side effects such as soft stools, nausea, vomiting, and stomach upset.