According to Wikipedia (
https://en.wikipedia.org/wiki/Citrulline ), Citrulline is an amino acid, and the body makes it from argenine. Quote from Wikipedia:
The release of nitric oxide is an integral part of getting an errection; that's probably why arginine and citruline are featured in various erection aid supplements.
The term "nitrate" doesn't show up on the page. Based on my knowledge of chemistry, it doesn't make sense to call citrulline a nitrate.
I ask about argenine because in the email I got when I purchased some BlueChew (generic Cialis, a.k.a. tadalafil), it says: