Our Menthol crystals have a minimum 99.5% L- menthol content. They are 100% pure and naturally extracted essential oils derived from peppermint and/or corn mint oil.  The Mentha Oil is carefully filtered to remove water and naturally occurring impurities. It is then cooled incrementally over a period of time. After cooling, the crystalline portion is isolated from the remaining dementholised oil (DMO). Pure grade for your benefit.