When I started natural skin care formulating in 2004, I was immediately freaked out about using essential oils because there were so many warnings out there about pregnancy, epilepsy etc. I enrolled in an aromatherapy course and got my certification within 6 months. I needed to practice safety with people's skin and wanted to use these wondrous oils in the most effective way possible. Since that time, my education has expanded on the daily. I've read so many books, I had to Marie Kondo them last month to make room in my office (which is now being overtaken by books on natural perfumery *womp womp*). I think formulators should know this much about essential oils before they put skin care products on the market with them in it.
Essential oils are fragrant but they aren't fragrance. I've noticed skin care companies use essential oils to create a scent in a formula with no regard to their properties. For instance, most citrus oils will make your skin more vulnerable to UV rays and should not be included in a leave on face product yet they are. Other times I see as many as 10 different essential oils in products and think why? I suspect it has to do with the scent and that is problematic. Not all essential oils are appropriate for the skin.
When blended into a formula safely, essential oils have some amazing skin care properties - anti-inflammatory, anti-microbial, healing, astringent, and antioxidant. When blended poorly, skin reacts.
I love essential oils more than the average person. I built an entire business around them. They are plants in liquid form therefore they are active, medicinal, and sometimes dangerous. They are meant to be handled and used in a very particular way that I think should be left to trained individuals.