English lavender (Lavandula angustifolia) essential oil has been used for centuries to reduce pain, combat infection, reduce anxiety and promote relaxation. Like other essential oils, lavender essential oil is very concentrated; at least 60 lbs of lavender flowers typically are used to make 16 fluid ounces of the oil. The oil is used in detergents, baked goods, candles, cosmetics, body powder, massage oil, shampoo, soap, perfume, and tea. It is also an ingredient in some breast enlargement pills and creams. Some cancer patients are receiving aromatherapy massage using lavender essential oil.
Breast cancer-related effects of eating lavender
Lavender essential oil has been shown to have a high antioxidant content and a component of lavender, perillyl alcohol, has been studied in cancer prevention. However, lavender essential oil (in the concentrations found in commercial hair care and body cream products) was reported to cause breast enlargement in otherwise healthy and normal boys in one well known 2007 New England Journal of Medicine article. While there have not been any follow up studies that confirmed the estrogenic effects of lavender-containing skin products, lavender essential oil appears to have estrogenic properties.
Use of lavender products can trigger allergic contact dermatitis and allergic reactions to lavender are not uncommon. For example, lavender flower satchels placed inside pillowcases have been found to cause facial rashes in some individuals. Lavender baby products probably should be avoided.
Note that while we are continually searching for new evidence specifically concerning lavender, there is not much interest in it among breast cancer researchers, so few studies are available.