(Click here to listen to the full episode.)

Your Sense of Smell: You Don’t Know What You Got, Until It’s Gone

Due to the pandemic, our sense of smell has come to be much more appreciated than in the past. One study found that 69 percent of people had immediate changes in their ability to taste or smell after the infection, and 14 percent still struggled three months later. Another study reported that 26% of people completely lost their sense of smell if infectious symptoms lasted greater than four weeks. The latest statistic in 2021 of the overall population estimates about 3% suffer from anosmia (the loss of smell) or hyposomia (minimal smell).

With many losing their capacity to recognize odors, people soon realized this sense plays a vital role in how we function and enjoy life. This is why I am so happy to have Hana Tisserand on this episode of the Essential Oil Revolution to discuss the topic of olfactory training, a technique used to recover the sense of smell. She also highlights the important work that she is doing at the Tisserand Institute as its COO and cofounder.

During the show, Hana offers her science-based and practical wisdom on essential oils, specifically on the topic of olfactory training. Hana has an incredible ability to synthesize research and provide detailed information in a manner that is concise, accurate, comprehensive, and understandable.

Below is a summary of what we cover in the full episode.


The Tisserand Institute’s Mission

Robert and his wife Hana Tisserand have provided research-based essential oils education at their Tisserand Institute since the beginning of the modern aromatherapy movement. They advocate for safety, education, and a balanced approach between science and experiential aromatherapy.

The name “Tisserand” is legendary in aromatherapy. Robert Tisserand wrote the first English book on essential oils, The Art of Aromatherapy in 1977. Today it is one of the most referenced books in aromatherapy.

I have personally learned so much from the articles that Hana has written herself and for her Institute, some are listed below. I have taken the knowledge I’ve gained and have applied it to my practice.


Hana’s Unique Background

Hanna has a unique perspective on how information about essential oils is sourced, processed, and communicated, stemming from her past experiences. Being raised in a family of doctors and nurses gave her an underlying interest in the workings of the human body, which previously manifested in her profession in medical translation.

Growing up in the Czech Republic, Hana was exposed to medicine that was integrative with conventional approaches and natural approaches sitting side-by-side. Her love of essential oils was reignited in her early 20s working both part-time in a new age store and in a perfume shop. She came to witness the power of smell as experimental in the perfume shop. When she met up with Robert Tisserand as his medical translator, her learning and appreciation for aromatherapy and essential oils expanded. And, as they say, “the rest is history.”


The Power of Smell

Smell is vital as a chemosensory experience. Hana stated that terpenes (a volatile compound found in essential oils) are the most communicated “language” in the world. This constituent is utilized by all creatures from single-celled organisms to mammals.

Our olfactory ability alerts us to danger, influences our taste, sparks our memory, and determines how we interact with the world on a sensory and hedonistic basis. A change in the capacity to smell has been linked to various disorders including Alzheimer’s disease, Parkinson’s disease, autism, and ADHD (attention deficit hypersensitivity disorder).

For this and many other reasons, The Smell and Taste Institute is advocating for using the sense of smell as a marker of health. (Stay tuned for a renowned smell coach exploring this concept in more detail on a future episode!)

You can read more about details on memory, smell, and essential oils in my previous publication here.


Do Essential Oils Work if You Can’t Smell?

Hana shared how essential oils biochemical properties still have an influence on our physiology and neurochemistry even if you can’t smell. They work on many receptors, including odor receptors, which influence our biochemisty. (The physiological impact of essential oils was also highlighted in our previous episode with Dr. Z and this blog.)

Hana also provided us an example of how we can experience peppermint oil without smelling it. When applied to the skin, it creates a cooling sensation. This is based on menthol’s impact on a specific receptor, TRMP8, and it is independent of olfaction.


Olfactory Training

During the episode, Hana really dives deep into the concept of olfactory training, which is all laid out in detail in her article. Her exquisite review of the science on this topic was why I asked her to discuss it on the show!

Here are some key points we discussed during the podcast:

  • The idea that we can train our nose to smell again came from a 1980s research study on androstenone, a mammalian pheromone that about 50% of people cannot smell.
  • Thomas Hummel of the Smell and Taste Clinic at Dresden University in Germany used these findings to expand it to olfactory disorders. He devised a protocol for olfactory training in hyposmic and anosmic patients, which has since been tested in many clinical studies.
  • In 2009, Hummel and colleagues published a study entitled Effects of Olfactory Training in Patients with Olfactory Loss that established the standard procedure. It was a prospective study on 56 people with some form of olfactory dysfunction.
  • The current protocol consists of systematic exposure to four odorant substances over a period of 4-12 weeks. These were selected based on the ‘odor prism’ theory established by Henning in 1916.
  • The odors represent four of the six categories in that theory: flowery, fruity, resinous, and aromatic. The odorants used have been the essential oils themselves or undiluted single chemicals: phenylethanol (rosy), 1,8-cineole (eucalyptus), citronellal (lemony) and eugenol (clove).
  • In olfactory training, each odor is smelled for ten seconds each morning and evening.
  • Olfactory training got revitalized with COVID-19. It can help people with all different types of ansomia.
  • The best results for smell retraining are for those who lost their sense of smell due to respiratory infections vs. from trauma to the olfactory nerve or bulb.
  • The COVID-19 virus damages the olfactory epithelium, but not the olfactory nerve, leading to smell loss.
  • The trigeminal nerve, a part of our chemosensory nerve, helps us sense dangerous odors. It holds an importance in determination if smell retraining will be successful.
  • You need to use essential oils and compounds that you have familiarity with for the best effects. This is based on the concept of neuroplasticity and re-educating your brain to the sense of smell. One study even showed olfactory training could improve brain function! (You can learn more about essential oils for neuroplasticity in this episode with Dr. Ben Perkus.)
  • Most research is done on single compounds from essential oils or essential oils vs. random scents. Essential oils likely offer the best results due to their multifactorial effects, such as being anti-inflammatory, anti-microbial, and impacting neurotransmitters.
  • Olfactory training takes time, so it’s important to be patient and give it at least eight weeks.


Education at the Tisserand Institute

The goal of the Tisserand Institute is to provide education and information that is accurate, safe, and accessible to all essential oil users vs. training for an aromatherapist certification. They offer a holistic approach to essential oils. The courses are aimed for consumers and practitioners alike. Topics include what oils to use, why to use them, and the evidence that exists.

The Tisserand Institute focuses on education versus selling courses. Their courses have cohorts with the oversight of the teachers to guide the students along the way. The strict start and end date ensures that once you purchase a course, you will finish it to get your diploma. They also offer single classes for those who want to “wade the water.”

It was an absolute pleasure to talk to Hana!

Don’t miss this amazing episode with one of the most influential people in aromatherapy.


Here’s an Overview of What You Will Learn in the Full Episode:

  1. The history of the Tisserand Institute and why it transformed from in-person integrative practitioner training in aromatherapy to online holistic training in essential oils.
  2. How Hana’s unique background influenced her to be an expert in essential oils. This includes her growing up in the Czech Republic, where integrative, conventional, and natural approaches co-exist in pharmacies side-by-side, and what led her to meet Robert Tisserand.
  3. The importance of smell as a chemosensory experience. For example, it alerts us to danger, influences our taste, stimulates memory, and determines how we interact with the world on a sensory and hedonistic basis.
  4. What component found in essential oils are the most communicated “language” in the world. These molecules are shared by every creature on the planet, from single-celled organisms to mammals.
  5. How essential oils constituents can still impact our biochemistry and physiology, even if one loses the ability to smell.
  6. The concept of olfactory training and how it works.
  7. Why specific essential oils or the constituents found within them, phenylethanol (rosy), 1,8-cineole (eucalyptus), citronellal (lemony) and eugenol (clove), are used in smell retraining. We also discuss if essential oils are more powerful than the single constituents.
  8. Why olfactory training works the best for those with infections and an intact, functioning trigeminal nerve.
  9. Why the aim of the Tisserand Institute is to provide education and information that is accurate, safe, and accessible to all essential oil users vs. preparing one for aromatherapist certification.
  10. One thing Hana does for self-care daily. (Hint it has to do with her love of aromas and hot beverages.)
  11. The one things Hana feels we should ditch and replace with instead to be healthier.
  12. Hana’s favorite essential oils hack.

Click here to listen in on the latest episode and access the show notes.


Bio of Hana Tisserand

Hana Tisserand is the COO, cofounder, and director of operations and communications of the Tisserand Institute, the global leader in online evidence-based essential oils education. Hana has been working at the Tisserand Institute since 2014 and she oversees the creation of its course content and curricula, moderates live webinars, supervises the staff, and teaches her own introductory classes. She also writes the Tisserand Institute newsletters, her own blog posts, and detailed scientific articles.

Hana has a unique perspective on how information about essential oils is sourced, processed, and communicated, stemming from her past experiences. She is a sought-after presenter for various prestigious aromatherapy events, including the Alliance of International Aromatherapists and NAHA (National Association for Holistic Aromatherapy).

Being raised in a family of doctors and nurses gave Hana an underlying interest in the workings of the human body, which previously manifested in her specialization in medical translation. Her love for science, essential oils, perfumes, and fragrances runs deep, as does her appreciation for fine teas and coffee.


Links to learn more about Hana, the Tisserand Institute, and their offerings:

Posts by Hana Tisserand and the Anosmia Video:

Hana’s Previous Episode on Essential Oils Revolution

Naturopathic Medicine and Holistic Resources for Hormonal, Mood, and Digestive Support

  • Stay Connected! Sign-up for my free weekly newsletter.
  • Free resources and more education on essential oils and mind-body wellness are available to you here.
  • Learn about my community membership program that provides full access to my essential oils database, essential oils course, Q&As, and exclusive content.
  • Tools for coping with isolation and separation.
  • The Essential Oil Revolution Podcast

Many blessings.



  1. https://www.mayoclinichealthsystem.org/hometown-health/featured-topic/q-and-a-covid-19-and-loss-of-smell-taste
  2. https://www.healthline.com/health-news/who-is-most-likely-to-lose-their-sense-of-smell-and-taste-from-covid-19#How-common-is-loss-of-taste-and-smell?
  3. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0256142
  4. https://www.cdc.gov/mmwr/volumes/70/wr/mm7036a1.htm?s_cid=mm7036a1_w
  5. https://www.uclahealth.org/news/why-your-sense-of-smell-is-important-to-your-health
  6. https://www.parkinson.org/understanding-parkinsons/non-movement-symptoms/loss-of-smell
  7. https://www.spectrumnews.org/news/test-detects-unusual-sense-of-smell-in-children-with-autism/
  8. https://www.nia.nih.gov/news/loss-smell-linked-alzheimers-cognitive-impairment-and-biomarkers
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3372562/
  10. https://pubmed.ncbi.nlm.nih.gov/18814862/
  11. https://www.smellgym.com/about
  12. https://www.medicalnewstoday.com/articles/what-are-terpenes#what-they-are
  13. https://www.townsendletter.com/Nov2016/sniff1116.html
  14. https://pubmed.ncbi.nlm.nih.gov/30630079/
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9891899/
  16. https://pubmed.ncbi.nlm.nih.gov/19235739/
  17. https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095930835

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Disclaimer: This material is for information purposes only and is not intended to diagnose, treat, or prescribe for any illness. You should check with your doctor regarding implementing any new strategies into your wellness regime. These statements have not been evaluated by the FDA. (Affiliation link.)

This information is applicable ONLY for therapeutic quality essential oils. This information DOES NOT apply to essential oils that have not been tested for purity and standardized constituents. There is no quality control in the United States, and oils labeled as “100% pure” need only to contain 5% of the actual oil. The rest of the bottle can be filled with fillers and sometimes toxic ingredients that can irritate the skin. The studies are not based solely on a specific brand of an essential oil, unless stated. Please read the full study for more information.

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