Smell

Table of Contents

Other names

olfaction
olfactory sense
sense of smell

Synopsis

Smell is one of the five primary senses and is mediated by the olfactory system, which allows the detection and perception of airborne chemical compounds. The olfactory receptors are located in the olfactory epithelium, a specialized tissue high in the nasal cavity. These receptors send signals through the olfactory nerve (cranial nerve I) to the olfactory bulb, and then to the brain regions responsible for memory, emotion, and recognition.

Unlike other senses, olfactory signals bypass the thalamus and go directly to the limbic system, which is why smells are so closely tied to emotional memories and instinctive responses. The sense of smell plays important roles in taste, danger detection (e.g., smoke, gas), appetite regulation, and interpersonal attraction.

The sense of smell can be impaired by a wide range of factors, and dysfunction may be temporary or permanent:

  • Anosmia: Complete loss of smell, which can result from viral infections (e.g., COVID-19), nasal blockages, or head injury.

  • Hyposmia: Reduced sense of smell, often due to aging, chronic sinusitis, or neurological conditions.

  • Phantosmia or parosmia: Distorted or phantom smells, sometimes related to trauma or neurological changes.

  • Neurodegenerative diseases: Conditions like Parkinson’s and Alzheimer’s often present early with loss of smell.

The olfactory system also plays a role in flavor perception, meaning smell loss can reduce enjoyment of food and lead to decreased appetite or unintentional weight loss.

Natural Remedies

Nasal irrigation: Saline rinses help clear mucus and reduce inflammation in the olfactory region.

Zinc and vitamin A: Important for epithelial and nerve cell regeneration in the nasal lining.

Omega-3 fatty acids: Support nerve membrane integrity and regeneration.

Smell training: Repeated exposure to a series of strong essential oils (e.g., clove, lemon, eucalyptus, rose) may help restore smell in cases of anosmia or parosmia.

Probiotics: May indirectly support smell by modulating the immune system and reducing chronic inflammation.

Avoid smoking and pollutants: These can damage olfactory receptors over time.