Since I use Hangsen e liquid I've looked around a little for info concerning their flavors. I read that their flavoring come from a company in France? I suppose that Hangsen exclusively makes/test their concentrates specifically for e-liquid use. I found this...
FAQs from Changning Hangsen Biotechnology Co., Ltd.
1. Is the ingredient diacetyl and diethylene glycol (DEG) used in your liquids?
Answer:
No. There is not diacetyl and diethylene glycol in our liquids Specifically, the concern is with Diacetyl. Diacetyl is sometimes used to add a buttery flavor to foods or e-liquids, but has been proven to cause health problems in some cases.
2. What does Hangsen e liquid contain and what safety standard?
Answer:
Safety Standard :
GMP , HACCP , ISO , KFDA ,SGS MSDS
formular :
1# Propylene Glycol ( Dow Chemical) , Nicotine, flavors
2# Polyethylene glycol (PEG 400) ( Dow Chemical), Nicotine, flavors
3# Vegetable Glycerin( Dow Chemical), Nicotine, flavors
All ingredients meet USP , see our SGS report
Hangsen’s European factory demonstrates a long term commitment to the e-cigarette and e-liquid industry, while offering 100% transparency for business customers concerned with both quality assurance and regulatory change.
According to Gerard Seczkowski, Director of Hangsen EU, “this plant represents the first step in our global manufacturing expansion plan, providing safer and localized products. Hangsen products are authentically made in Europe, with ingredients from France, Italy, Germany and the United Kingdom.” Hangsen has passed ISO9001 and GMP International Quality Assurance. The products have received SGS, TUV, CE, ROHS certificates.
Anyhoo, don't see where any independent test have been done...other than saying their liquids don't contain any harmful ingredients...but then that's what FW claims also