Widely used plant that’s a member of the mint family. May be listed by its Latin names Lavandula angustifolia or Lavandula officinalis. Primarily a fragrance ingredient, it may have beneficial properties for skin but is also a potential sensitizer due to its fragrance components. The oil form is more likely to aggravate skin than the extract form, especially if you can detect lavender’s distinctive scent.
In-vitro research indicates that components of lavender oil, specifically linalool and linalyl acetate, can have damaging effects on skin in as low a concentration as 0.25%. When exposed to air, these components oxidize, meaning their potential for causing a reaction increases.
If you’re wondering why lavender oil doesn’t appear to be problematic for some people, it’s because research has demonstrated that you don’t always need to immediately see or feel the sensitizing effects for your skin to suffer damage.
References for this information:
British Journal of Dermatology, August 2014, pages 292-297
Skin Pharmacology and Physiology, May 2008, pages 191-202
Contact Dermatitis, April 2008, pages 143-150 and January 2008, pages 9-14
Cell Proliferation, June 2004, pages 221-229
Journal of the Society of Cosmetic Chemists, January-February 1992, pages 49-54