There are no standard definitions within the cosmetic and personal care product industry for natural or synthetic. However, the National Organic Program (NOP) does have definitions that are accepted within the organic food industry.
Since many people are interested in knowing if the ingredients in their products are natural or synthetic, the NOP definitions were used to define the ingredients in the Cosmetic Ingredient List as natural or synthetic:
"A substance that is derived from mineral, plant, or animal matter and does not undergo a synthetic process as defined in section 6502(21) of the Act (7 U.S.C. 6502(21)). For the purposes of this part, nonsynthetic is used as a synonym for natural as the term is used in the Act."
"A substance that is formulated or manufactured by a chemical process or by a process that chemically changes a substance extracted from naturally occurring plant, animal, or mineral sources, except that such term shall not apply to substances created by naturally occurring biological processes."
You can find out if the ingredients in your skin care products contain natural or synthetic ingredients in the book Dying To Look Good.
Find cosmetics and personal care products with natural ingredients in Dying To Look Good and on DyingToLookGood.com