Medical Grade Vegetable Glycerin - Non-Toxic, 100% Pure https://www.amazon.com/dp/B08PTX23RQ/ref=cm_sw_r_cp_api_glt_i_KQC76FDBEKZBFR19T6VJ?_encoding=UTF8&psc=1 And they’re not harsh, but every time I vape anything I’ve made it makes me wheeze. And .3% sorry I thought I put the decimal earlier. The nicotine has a light brown color to it, and it has a some what sweet smell too. I could of sworn it said it was either colorless or odorless nicotine when I ordered it though now that I think of it.