It is in my scalp concoction. I think the present incarnation -- of many incarnations over the last three years -- is aloe vera gel, avocado, castor and mustard oils, cayenne extract, horsetail extract, kelp extract, sulphur and yucca. When it starts getting low and I add more oils to it and aloe vera, sometimes I forget to add more mustard oil. When I remember a few days later and add it, the warmth, stimulation, tingling factor increases 10-fold.