There are probably not that many until the FDA starts requiring certification. It will happen at some point. There are suppliers who claim FDA certified/FDA certified ingredients.
Here's one that claims FDA certification.
Wholesale E-Liquid Products and Supplies, FDA certified E-Liquid Lab, cGMP
I think it's more about using FDA approved ingredients at this point.
Hmm wholesaler. I wonder what makes them a FDA certified lab? I can see the ingredients being FDA approved, that's a well known fact that all the ingredients that goes into making e-liquid are USP FDA approved. Nicotine that is sourced is FDA approved. It is the lab part that becomes the sticking point. If our vendors use FDA approved ingredients, technically could They say they are FDA approved? Or is it the "Lab" part that makes the difference?
Interesting.