Parosmia [pahr-OZE-mee-ah] is a change in the normal perception of odours, such as when the smell of something familiar is distorted, or when something that normally smells pleasant now smells foul.

Anosmia refers to a total loss of sense of smell. Anosmia and parosmia are both common symptoms of COVID-19, along with dysgeusia (a distorted sense of taste) and ageusia (a total loss of sense of taste).

Olfactory Training Therapy

Also called “smell training,” this approach involves sniffing various substances for several seconds at a time. You repeat the process twice a day for several months.

Parosmia Kits
Each course consists of smelling the essential oils one by one twice a day.

COURSE 1: $45 in a plain cotton drawstring bag
Lemon Essential Oil Social Enterprise 10ml
Rose Absolute 100%, Bulgarian, Social Enterprise 1ml
Clove Bud Essential Oil, Social Enterprise 10ml
Eucalyptus Globulus Essential Oil, Social Enterprise 10ml

COURSE 2
menthol
thyme
tangerine
jasmine

COURSE 3
green tea
bergamot
rosemary
gardenia

Instructions:Choose two times each day that you will sit quietly to do your scent training. It may be helpful to do the sessions when you are a bit hungry, such as before breakfast and before dinner.Choose a quiet space: Find a distraction-free area for your sessions, and whenever possible, do your scent training there.Inhale the scent gently for 10–20 seconds, focusing on recalling the memory of the scent. Smell each essential oil and think about its taste, its scent, and bring up any and all memories you have associated with it. Do this for each of the scents. Write notes about your training, and record any observations you have. You may keep this journal like a chart, or it may be more effective to record your memories, your reflections and your sensations and keep these details private. Continue the training for at least 3 months.Once you are able to smell the essential oils in Course 1, you are ready to begin Course 2, and then, when you are able to smell those, you can move on to Course 3. The essential oils used in the courses are specifically designed to activate critical pathways between your nose and your brain. Therefore, it is important to complete all three courses in order to fully regain the scope of your sense of smell.You have purchased Course 1 of the Scent Training Kit for anosmia. Here are the essential oils in this first kit and what pathways their components activate:Lemon (Citrus × limon (L.) Osbeck) essential oil is dominated by (+)-limonene, which has a fresh, pleasant, orange-like smell, and has been described as member of the “fruity” category in Henning's classification [13], and a member of the “Citrus” category in Roudnitska's classification [10].Clove Bud (Syzygium aromaticum (L.) Merr. & L.M.Perry) essential oil, characterized by a spicy odour, is dominated by the aromatic aldehyde eugenol, which binds to A1 [8], V3 [15] and M8 [16] TRP channels. This essential oil belongs to the “spice” category in Henning's [13] and Roudnitska's [10] classifications.
Rose absolute (Rosa damascena)  represents the "flowery" category in the classic 4-scent protocol—along with lemon, clove, and eucalyptus—designed to stimulate neural pathways through daily, focused, and deep inhalation. Eucalyptus (Eucalyptus globulus Labill) essential oil is dominated by the monoterpenic oxide 1,8-cineole, which has a characteristic penetrating fresh smell and binds to M8 [19], A1 [19] and V3 [9] TRP channels. This essential oil belongs to the “resinous/ethereal” category in Henning's classification [13].
Olfactory training with essential oils for patients with post-COVID-19 smell dysfunction: A case seriesDavide Donelli a,⁎, Michele Antonelli a, Marco Valussi bAuthor informationArticle notesCopyright and License informationPMCID: PMC10102705  PMID: 37163157https://pmc.ncbi.nlm.nih.gov/articles/PMC10102705/The 30-day protocol included two olfactory training sessions every day (one in the morning and the other one in the evening), each of them lasting approximately 15 min. During every session, the patients had to smell a set of ten plant-derived essential oils through different patterns (deep inhalation, rapid sniffing) and in a pre-specified order, as follows:1Peppermint (Mentha x piperita L.) essential oil is dominated by (-)-menthol, which has a refreshing, cool and mint note, and binds to M8 [7], A1 [8] and V3 [9] TRP channels.2Lavender (hybrid) (Lavandula x intermedia Emeric ex Loisel) essential oil is dominated by R-(-)-linalool, which has a flowery-fresh odor, has been described as “herbaceous” in Roudnitska's classification [10], and binds to A1 [11] and M8 [12] TRP channels.3Lemon (Citrus × limon (L.) Osbeck) essential oil is dominated by (+)-limonene, which has a fresh, pleasant, orange-like smell, and has been described as member of the “fruity” category in Henning's classification [13], and a member of the “Citrus” category in Roudnitska's classification [10].4Red spruce (Picea abies (L.) H. Karst) essential oil is dominated by camphene, alpha- and beta-pinenes, and has a typical pine-like odor.5Frankincense (Boswellia sacra Flueck) essential oil is dominated by (E)-β-ocimene and monocyclic monoterpene hydrocarbons, such as (+)-limonene. (+)-Limonene has a fresh, pleasant and orange-like smell.6Hyssop CT. pinocamphone (Hyssopus officinalis L.) essential oil is dominated by monoterpene bicyclic ketones, such as pinocamphone and iso-pinocamphone, and belongs to the “spice” and “herbaceous” categories in Roudnitska's classification [10].7Cinnamon (Cinnamomum verum J. Presl) essential oil is dominated by the aromatic aldehyde cinnamaldehyde, which binds to A1 [8] and V3 [14] TRP channels, and has a warm-spicy odor. This essential oil belongs to the “spice” category in Roudnitska's classification [10].8Cloves (Syzygium aromaticum (L.) Merr. & L.M.Perry) essential oil, characterized by a spicy odor, is dominated by the aromatic aldehyde eugenol, which binds to A1 [8], V3 [15] and M8 [16] TRP channels. This essential oil belongs to the “spice” category in Henning's [13] and Roudnitska's [10] classifications.9Savory (Satureja montana L.) essential oil is dominated by the terpenic phenol carvacrol, which binds to A1 [15], V1 [17], V3 [15] and M7 [18] TRP channels. This essential oil belongs to the “herbaceous” category in Roudnitska's classification [10].10Eucalyptus (Eucalyptus globulus Labill) essential oil is dominated by the monoterpenic oxide 1,8-cineole, which has a characteristic penetrating fresh smell and binds to M8 [19], A1 [19] and V3 [9] TRP channels. This essential oil belongs to the “resinous/ethereal” category in Henning's classification [13].