Vanillin is typically found in the actual herb vanilla, and vanilla extract.
I use vanillin to make cakes, hot chocolate and vanilla milk with Splenda (sucralose).
I worked at a food manufacturing plant before and they had big 25 lbs boxes or so of vanillin. Really sticky smelly stuff. Maybe If I dunked my head in a box of it I would be cured today.
If its the real deal it might have health benefits, but a lot of commercial vanilla products are synthetic or just a flavouring agent and have no health benefits.
A 50ml bottle of real vanilla extract would typically cost around 15$.