From Psychology to Genetics: How Molecular Science Can Revolutionize Olfactory Training

Olfaction is an essential bridge to our well-being, connecting us to memories, emotions, and our safety. Currently, Olfactory Training is the standard method to assist in the recovery of this sense after losses caused by viruses or other factors. However, a recent study published in the scientific journal The Laryngoscope suggests a technological leap: moving from a practice based on century-old psychological theories to a precision approach based on our genes.

Henning’s Legacy: Why do we train with Rose, Lemon, Eucalyptus, and Clove?

The use of these four specific scents dates back to 1916 and is based on the “Odor Prism” by psychologist Hans Henning. Henning believed that all human olfactory perceptions could be organized into basic psychological categories. Although this method has demonstrated clinical efficacy over the years, it was not designed based on the molecular biology of our cells. The new study reveals that this classical combination activates approximately 39.2% of the diversity of receptors in the human nose—a relevant number, but with significant room for optimization.

The Biology of Survival: “Use It or Lose It”

The science of recovery is based on neuroplasticity and cellular survival. Our system operates under the rule of activity-dependent survival: the neurons in the nose must be stimulated to remain alive and correctly connected to the brain.

Activated neurons show increased survival compared to those that are not activated.
Genetic studies demonstrate that neurons lacking activity gradually lose their function and disappear from the olfactory epithelium.
Therefore, the goal of optimized training is to “wake up” the widest possible variety of receptors to keep the system functional.

The New Frontier: Molecular Data and Transcriptomics

To increase the effectiveness of olfactory training, investigators analyzed the M2OR database, which synthesizes 25 years of research on how hundreds of odors interact with 385 types of human olfactory receptors (ORs).

Through transcriptomics — the study of which genes are most active in our mucosa — the team identified the receptors that are most abundant and functionally crucial for humans.
In humans, these highly expressed receptors are specialized in detecting important food odors.
The goal was to find the minimum combination of substances capable of stimulating the largest part of the human olfactory repertoire.

The Optimized Kit and Sensory Experience

The data analysis resulted in the proposal of a new combination of four molecules:

Galaxolide: Possesses a musky and floral aroma. In the study, it was revealed to be the most potent molecule, activating 275 types of receptors on its own.
Eugenyl Acetate: Combines the scent of cloves with floral notes. It brings a familiar warmth but with a delicacy superior to pure clove.
(-)-Menthol: Provides a cool and refreshing minty sensation. It is fundamental for activating receptors linked to freshness in the nasal passages.
Geranyl Acetate: Presents an aroma that mixes herbal and floral notes. It evokes the freshness of green leaves and gardens.

Together, these substances can theoretically activate 83.9% of human receptors, covering nearly 70% of our nose’s total expression capacity.

Transparency and Clinical Validation

As with all scientific progress, it is vital to treat this data with rigor. This is an initial study based on computer simulations (in silico).

Although the theoretical results are promising and offer a more solid scientific foundation than Henning’s model, their actual superiority must be confirmed through clinical validation with real patients.
Additionally, individual genetic variations can influence how each person responds to these stimuli.

At the Olfactory Research Center, we believe that this evidence-based path is what will allow for more precise, safe, and personalized treatments for olfactory dysfunctions in the future.

Bibliographic Reference

Nishijima H, Holbrook EH, Schwob JE, Mori E, Kagoya R, Ogawa K, Horikiri K, Kondo K. Optimizing Odorants for Olfactory Training Based on Olfactory Receptor-Ligand Pair Analysis. Laryngoscope. 2026 Jan;136(1):384-394. doi: 10.1002/lary.32437. Epub 2025 Jul 18. PMID: 40679176; PMCID: PMC12770814.