Tinctures are either glycerin or alcohol based. In either case, you would need to add pharmacy grade vegetable glycerin (VG) in order to produce a quality vape. The amount of VG you add depends on a number of factors... composition of your herbal tincture (make VERY SURE) you know all the ingredients used to compound the tincture, chemicals may have been added that should not be vaped! I have an educational background in botanical medicines and often make tinctures for personal use. I don't use cannabis; however, there are other medicinal herbs that can be used for vaping.

Visit this site: http://www.mountainroseherbs.com/tea_bev/tea_bev.html for herbs you can make your own tinctures from that can be vaped.