What are Essential Oil Chemotypes? - A Quick Guide

What are Essential Oil Chemotypes? - A Quick Guide

When buying and using essential oils you may come across the word chemotype or see something like this:

Rosemary ct. camphor or the botanical name of Rosemarinus officinalis ct. camphor

The ct. abbreviation means "chemotype". In this example, "ct. camphor" refers to the chemotype of rosemary, which contains high levels of camphor. You may also see it simply written Rosemary Camphor.

After reading this quick guide on essential oil chemotypes you will have a greater understanding of what they are and why they are important to aromatherapy.

What are Essential Oil Chemotypes? - A Quick Guide by Loving Essential Oils

What are Essential Oil Chemotypes?

"Chemotype" means a different chemical type.

Chemotypes are plants of the same genus and species which look identical but have a variation in the chemical components of their essential oils due to different conditions of growth. The listed chemotype is the oil’s overriding constituent. 

Not all plants produce chemotypes, but some have the genetic ability to produce different chemical constituents based on environmental factors.

Here are a few environmental factors that may produce different chemotypes:

  • Climate
  • Growing elevation of plant
  • Growing condition of plant

For example, in Basil Linalool, there is a high linalool count present. Here is a GC/MS from Plant Therapy:

essential oil chemotype - basil linalool

You see that the constituent linalool is at 51.8%. That is the main component of this basil essential oil, and that is why it is listed as Basil Linalool:

Why Essential Oil Chemotypes Matter?

Knowing the chemotype of your oil can help you choose the right essential oil for your purpose.

When it comes to essential oils, different chemotypes will have different therapeutic properties, aromas, and even safety concerns.

Be aware that not all essential oil companies will identify the chemotype of the essential oil on the label. If it is an essential oil that you know has chemotypes, then you can look at the testing done on the oil to see what chemical component has the highest percentage.

Like the example above of the GC/MS test from Plant Therapy, it shows that linalool has the highest percentage. So you know that chemotype is linalool and that your essential oil is rich in the chemical component of linalool.

Doterra® Thyme bottle label does not differentiate what chemotype it is, but when looking at the main chemical components, they list Thymol. So you can conclude that they offer Thymus vulgaris ct. thymol.

Plant Therapy clearly has chemotypes listed on the their bottles like this:

Most Common Essential Oil Chemotypes

When looking at the essential oil chemotypes, the botanical names will be the same but the ct. will highlight the main chemical component the oil is made of.

Remember I mentioned that not all plants produce chemotypes, here are the common ones you will more than likely come across.

Essential Oil


  • Thymus vulgaris ct. thymol
  • Thymus vulgaris ct. linalool
  • Thymus vulgaris ct. carvacrol
  • Thymus vulgaris ct. geraniol
  • Rosmarinus officinalis ct. camphor
  • Rosmarinus officinalis ct. 1,8-cineole
  • Rosmarinus officinalis ct. verbenone
  • Salvia officinalis ct. 1,8-cineole
  • Salvia officinalis ct. thujone
  • Ocimum basilicum ct. linalool
  • Ocimum basilicum ct. carvacrol
  • Ocimum basilicum ct. eugenol


While this is not an exhaustive list, it is the most common essential oil chemotypes you will come across for aromatherapy.

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What are Essential Oil Chemotypes? - A Quick Guide by Loving Essential Oils

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What are Essential Oil Chemotypes? - A Quick Guide by Loving Essential Oils


Jennifer Lane - Certified Aromatherapist

BIO: Owner and founder of Loving Essential Oils. I am a Registered Nurse and Certified Aromatherapist that loves to look toward essential oils and aromatherapy for all natural physical, emotional and spiritual support. I love creating and sharing DIY Essential Oil Recipes & Blends. Thank you so much for allowing me to be part of your essential oil journey!

*These statements have not been evaluated by the Food and Drug Administration. The information provided here is not intended to diagnose, treat, cure or prevent disease, nor is it a substitute for medical advice. As an Amazon Associate I earn from qualifying purchases. Post may include affiliate links. See full disclaimer.