Great questions! Kudos to you in taking an active role in what you can do to keep your body healthy and strong....
To answer your first question, because essential oils should be composed of only pure, volatile aromatic compounds, they do not contain estrogen, phytoestrogens, or other hormones. Appropriate use of high quality essential oils will not cause any negative hormone issues. At Statera, we use and recommend dōTERRA essential oils.
Your next question, "As a ER+ breast cancer survivor, I am wondering if I need to avoid certain oils. Also are skin care products containing hyaluronic acid OK to use for ER+ breast cancer survivors? I am avoiding products containing parabens and phthalates as much as possible.," is a little more difficult to answer, as there is some conflicting information about the use of HA by ER+ breast cancer survivors. Some studies suggest that HA (more so taken orally/introduced systemically) could cause proliferation of cancer cells that are currently present. HA helps with the growth and regeneration of cells and the HA itself does not differentiate between good and bad cells. Although very little product, if any, goes systematically when applied topically we still would recommend caution with its' use. Also, the majority of products that contain HA are going to have some type of preservative in it, like parabens, for antimicrobial purposes and to extend shelf life. Bottom line, we always recommend patients with a history of cancer to consult with their oncologist.
~Julie Haufe, Massage Therapist, Essential Oils Certification Specialist