I sent an email to Barnloft asking them what was in the 10% that wasn't listed as plant derived and this was their reply: "All we can tell you is that it is synthetic. At only 10%, using it at 1% will still make your wax base 99.9% natural. If you add fragrances that are not essential oils or dyes, there will be much more addition of synthetics to your formula than this additive will bring you. Please let me know if I can be of further help."