Look for the full botanical (Latin) name on the label – for example, Lavandula angustifolia for true lavender. Reputable suppliers provide a Gas Chromatography/Mass Spectrometry (GC/MS) test report or Certificate of Analysis (COA), which confirms the oil’s chemical composition and purity. Avoid oils priced suspiciously low, as pure plant extracts require significant raw material. When buying online, stick to trusted sources like our organic essential oils collection or our conventional essential oils range, both of which are tested for purity and quality.