Essential Oil Kinetics Masterclass 2e

What our body does to essential oils


What happens after an essential oil comes in contact with your body? While it’s true that specific oils have certain properties, choosing the right oil or blend for an ailment is only a part of the solution. Where do you apply? In what dose or dilution? How frequently and for how long? The pathways that essential oils take in the body, and their mechanisms, can greatly influence therapeutic efficacy.

Enrollment OPEN !

This six-part online certification course looks at what happens in our body after we apply essential oils to it

Over six weekly lessons, Dr. Petra Ratajc will introduce you to pharmacokinetics – the journey that essential oil constituents take as they move through your body – and what this means for effective application. We’ll compare psychological and pharmacological mechanisms, look at the blood-brain barrier, and the fascinating “nose-to-brain” route. Finally, we’ll discuss appropriate dose, dilution, delivery system, and mode of application, based on everything we have learned.

We’re not going to sugarcoat it – you can’t armchair this one. But while this is an intensive course with prerequisite readings of anatomy and neuroscience, our teaching format makes these concepts easily accessible. Plus, Petra and the TI team are here for clarification and support throughout.

Up for the challenge? Then join Petra in this Masterclass, and chart your own path to making optimum therapeutic decisions. All lessons have been updated based on new research and past student feedback.

What You Get in the Course

Six live online classes instructed by Dr. Petra Ratajc. All lessons are recorded for your later viewing.

Ample time for participant’s questions during live Q&A sessions.

Downloadable handouts (over 300 slides) and course notes with links to additional resources.

Online forum for your questions and interaction with Petra, the TI team and classmates.

A signed Certificate of Completion from the Tisserand Institute.

Ongoing access to recorded sessions for six months after course completion, plus reenrollment option for future course runs.

You will be given a quick and easy-to-digest anatomy primer for each of the classes to make sure you get the most out of the content.

Petra Ratajc, PhD

Biologist | Researcher | Educator

On her myth-busting plant biology blog, The PhytoVolatilome, Petra refers to herself as an aromatic plants enthusiast. But click through to just one of her posts, and it’s obvious that she’s so much more than that – and backed by some serious credentials.

Petra Ratajc has a post-graduate degree in Biological and Biotechnical Sciences from the University of Ljubljana. Her PhD extends from fieldwork to molecular research in the quality, safety and efficacy of aromatic herbs and their essential oils. Petra specializes in medicinal and aromatic plants, secondary plant metabolites, pharmacognosy and pharmacology – specifically focused on plant volatile constituents.

Besides bringing an unequivocal depth of knowledge to this course, Petra is an experienced lecturer and presenter at various seminars and workshops.

Full 2024 Schedule

Essential Oil Kinetics 2e (Starting July 24, 2024)

This course is being re-released with new & updated information. All lessons will be held live at 10am Pacific with a live Q&A to follow. Lessons last approximately 1 hour and Q&A sessions average 30-60 minutes. All sessions are recorded and will be uploaded to the platform for those that cannot attend live.

Lesson 1 + Q&A: July 24, 2024
Lesson 2 + Q&A: July 31, 2024
Lesson 3 + Q&A: August 7, 2024
Lesson 4 + Q&A: August 14, 2024
Lesson 5 + Q&A: August 21, 2024
Lesson 6 + Q&A: August 28, 2024

Course Breakdown – starting July 2024!

Lesson 1 - Human Body Networks and Pathways
  • The structure of the body, and how it processes nutrients and foreign molecules
  • Comparing single substance medicines and natural complex medicines
  • How essential oil constituents are absorbed, distributed, metabolized, and eliminated
  • The difference between pharmacological and psychological mechanisms
Lesson 2 - Inhalation & the Olfactory System
  • The olfactory system and the brain
  • Olfactory receptors and the sense of smell: pathways, mechanisms, anosmias
  • How essential oils influence the body and mind via the olfactory system
  • The psychological effects of odor; hedonics, semantics, expectation
Lesson 3 - Inhalation & the Respiratory System
  • The respiratory system, and what happens when we inhale essential oils
  • How compounds transfer from the air to the lungs to the bloodstream
  • The blood-brain barrier and the “nose-to-brain” route
  • When and how to use respiratory inhalation as a therapeutic method
Lesson 4 - Topical Application & Effects
  • The structure of the skin, and factors that influence permeability
  • Penetration pathways, penetration enhancers, and how much is absorbed
  • Blending essential oils for optimal absorption
  • Safety issues, and when to apply essential oils topically as a therapeutic method
Lesson 5 - Ingestion & the Internal Debate
  • The digestive system, and the route essential oils take after ingestion
  • Liver metabolism and the bioavailabity of essential oil constituents
  • Using essential oils for flavor compared to therapeutic doses and effects
  • Determining when the ingestion of essential oils is appropriate
Lesson 6 - Practical Application Guidelines
  • Calculating and measuring appropriate doses and dilutions
  • How essential oil blending affects calculations of efficacy and safety
  • The therapeutic window, cumulative dosing, and at-risk groups
  • Deciding on appropriate modes of application, delivery systems, and protocols

When You Complete the Course


Your certificate will be signed by Dr. Petra Ratajc and Robert Tisserand, and issued by the Tisserand Institute – leaders of evidence-based instruction on the therapeutic use of essential oils.

Course completion and certification demonstrates your in-depth understanding of how essential oils are absorbed and metabolized by the body, and your knowledge of the safe and effective applications of essential oils for aromatherapy clients.

What previous students say about our courses:

I really appreciated the applicability of the course to my practice. It helps me to be more knowledgable in determining the right application for a concern and the basics of why that is. My plans are to start a business (whenever COVID-19 allows that) and I feel so much more equipped with a solid foundation. I am very grateful this class was offered and came when it did! Petra was a wonderful and knowledgable instructor! I know this has been mentioned, but it would be helpful to have links to the research included in the materials. ~ Mary Moldestad
Communication with Hana was excellent, always informative and relevant. Admin has been second to none. The delivery of the programme was very professional and with good guidance. Thank you ~ Julie Hall
It was science/research based and practical information that actually applies to our industry. No fluff and you answer our questions. I’ve had classes where they delete my questions because they don’t know how to answer them. I don’t expect perfection because we are all human, so if someone doesn’t know the answer I understand. You all are amazing and so appreciate in making us better at what we do! ~ Jessica Faleide
Excellent pre-information, very informative videos, very wide spectrum of information concerning this theme 👏 ~ Gabi Peham
I like the way that Petra helped the attendee work through the minefield of information out there to bring the knowledge that we have into practical application. Having not trained in the sciences I find your work useful straightforward accessible deep information, that increases the magic of the therapy. What an extraordinary area to be working with and developing. To quote Victor Hug Victor Hugo — ‘Nothing is more powerful than an idea whose time has come” I work teaching midwives in National Health Service in UK and to have Petra and Robert’s growing knowledge as solid backup is invaluable in to work with. Thank you. Thank you Hana for your seamless graceful administrations too. ~ Lindsay Woodman

Discover how to make decisions about essential oils based on your unique situation and deepen your therapeutic practice with this unique class.


Will there be notes for me to review?
Yes. Each lesson comes with printable handouts of the slides used in the lesson, and additional lesson notes. These are sent to you before each lesson and are for you to keep and refer to at any time.
I am a certified aromatherapist. Will I learn anything new?
Many of our students have commented that our courses helped them grasp what they learned elsewhere in more detail, or complemented their previous education. Some of our students are lifelong learners, and some are teachers.
I am new to essential oils. Is this course for me?
We will let one of our previous students answer this one:

“The information presented is appropriate for all levels, and although I am just beginning my aromatherapy journey it all makes sense.”

Will there be assessments or exams? What kind?

Each weekly lesson is followed by a multiple choice quiz, and there is a summary test at the end of each course. Passing both the weekly quizzes and the final tests is a requirement for certification.

You will be given enough time to prepare for the test as well as three attempts to pass. 

Will I be able to ask questions?

Absolutely! In addition to the live Q&A sessions, you can post your questions in the dedicated student forums where the tutor and the TI team will address them. 

What if I cannot participate on a live session?

All of our live sessions are recorded and are posted on the learning platform within 24 hours so you can watch them, or rewatch as needed during the course. 

How long will I have access to the recordings?

You will have access to all the videos for at least four weeks after the last lesson (see course description for clarification as this changes for individual courses). All the printable materials (notes, handouts, charts, etc.) are of course yours to keep for reference forever.

Do you offer continuing education credits?

Because we have students from all over the world and of many professions we are not able to offer credits for specific organizations – there are simply too many. However, we issue a confirmation of CE hours gained on the course that you can apply with your professional organization and will be happy to assist with any additional documentation.

At the moment, we are an Approved Continuing Education Provider with NAHA. 

What if I fall behind or cannot attend classes?
We have found that running classes on specific dates works best to help you finish a program. You join a class of students, and learn along with them. Many students help each other with queries, and of course our tutors are there too. That said, if you miss a few classes you should be still able to comfortably jump right back in and if you do fall behind you can request extra time. Of course this cannot be indefinite, but we do our best to help you get your certificate.