Assuring the Identity and Purity of NOW® Solutions Essential Oils


Tests show that NOW peppermint and other oils are pure and unadulterated

Essential Oils are plants’ naturally occurring volatile oils, with each having the characteristic aroma of the plant part from which it was derived. These solvent-free oils are "neat"; meaning they have not been diluted with any additives. NOW's citrus fruit essential oils are 100% cold pressed (expressed). Our other essential oils are 100% steam distilled.

The integrity of an essential oil is determined by identifying both the botanical and the part of the botanical from which it was derived, plus controlling other key factors such as proper harvesting and gentle extraction methods. NOW Foods sells pure essential oils produced from quality botanicals harvested at the appropriate time and then processed by world-class distillers utilizing either steam-distillation or cold pressing to carefully extract the delicate oils.

There is no official evidence-based grading system for essential oils; claims of quality “grades” are typically just unsubstantiated marketing hype. Many aromatherapy professionals use NOW® Solutions essential oils with great success and satisfaction…

How do we determine the specifications for testing our essential oils? NOW® Solutions’ essential oil specifications were carefully developed by experienced chemists based on the appropriate criteria for each oil’s aromatherapy use. This includes testing for identity and specific chemical constituents within ranges identified in our specifications, as well as testing to assure that the samples are unadulterated pure natural essential oils. To this end we utilize only reputable distillers/pressers providing lot-specific Certificates of Analysis and employ several analytical techniques in identifying each essential oil, performing the appropriate testing, and screening against adulteration. One such technique is HPTLC, or High Performance Thin Layer Chromatography.

As an example, the HPTLC chromatogram depicted here compares two samples of Mentha piperita Peppermint essential oil with its common adulterant, Mentha arvensis Corn Mint essential oil. The side-by-side essential oil chromatographs are of the NOW® Mentha piperita Peppermint Oil (#1), a Mentha piperita Peppermint Oil from another reputable high quality brand (#2) and Mentha arvensis Corn Mint Oil (#3). The essential oil component that distinguishes the Mentha piperita oils from the Mentha arvensis oil is iso-iso-pulegol (iso-pulegol). It is identified in the Corn Mint Oil chromatogram #3, but is absent in the Peppermint Oil chromatograms #1 and #2, thereby indicating conclusively that both the NOW Mentha piperita Peppermint Oil and the other brand shown are genuine and unadulterated. [For more information on HPTLC in general, please click on this link: /Quality/Quality-Notes/078268.htm]

Selecting Testing Parameters for Essential Oils

There are a number of essential oil standards established by various organizations, including AFNOR, ISO, FCC, BP Codex, EOA (Essential Oils Association), and others. Over the years since these standards were created, essential oil plant cultivation has significantly changed. The cultivars being produced today, and in different regions of the world than before, now contain oils that often no longer correspond to these older standards.

Because inevitable genetic differences between plant varieties within the same species result in different responses to their environment, a wide range of natural variation in plants’ chemistries have been observed. This natural variation in essential oil plants has been compared with other well-known regional and seasonal variations in plant products such as olive oil and wine, even if harvested from the same trees or vines. A single species can have different chemotypes, each with different ratios of chemical constituents, which confound testing to now-outdated standards. If you are not testing for the specific cultivar – not just species - of plant that is used to make your oils, then the results would not be valid even if the sample apparently “passed” the test.

In the case of Peppermint Essential Oil, for example, it is specified that a test designed for American-grown Mentha piperita is inappropriate for testing Asian-grown Mentha piperita, even though they are the same species. Because this is a known and acceptable natural variation, informed essential oil scientists like ours know that it is not appropriate to subject our Indian-grown Peppermint Essential Oil to that particular test. Instead, we specify that our products are tested appropriately to their species, origin, parts of the plant used, key constituent levels, possible adulterants, and important aromatherapy characteristics including organoleptics (human sensory testing).

As another example of how varied chemotypes of the same kind of oil can be, Thyme Oil has two notable constituents – Thymol and Carvacrol – and three main chemotypes, with obviously very different ratios of these notable constituents in each chemotype that would defy passing any simple test standard (taken from the reference book “Essential Oil Safety”):

  • The Thymol Chemotype (Thymol 32-43% and Carvacrol 1-5%)
  • The Carvacrol Chemotype (Thymol 1-13% and Carvacrol 23-44%)
  • The Thymol/Carvacrol Chemotype (Thymol 1-16% and Carvacrol 21-37%)

Because of these legitimate issues, adherence to a third-party standard - any standard - is simply not directly relevant to the quality of an essential oil used for aromatherapy. This explains why we don’t use inappropriate and outdated standards for testing our essential oils. Our specifications are designed to be relevant to modern aromatherapy uses by assuring quality and purity, and detecting adulteration.

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