Definition
Selective anosmia, also called specific anosmia, describes the inability to detect one specific odor molecule while the sense of smell stays fully functional for every other odor (source: Wikipedia). It differs from general anosmia, the total loss of smell, and from hyposmia, an overall drop in sensitivity. The phenomenon was first described by John Amoore in the 1960s and 1970s.
Molecules involved
Musks, especially macrocyclic musks and Galaxolide, affect 30 to 40 percent of the population (source: Whissell-Buechy and Amoore, 1973). Androstenone, a steroidal pheromone first identified in pigs, is undetectable for roughly half of humans; among those who perceive it, half report it as foul and half as pleasant, a split documented by Keller et al. in Nature in 2007. Beta-ionone, the headline violet note, and isovaleric acid are also well studied cases.
Genetic basis
The mechanism comes down to variants in olfactory receptor genes, the OR genes, identified through the work of Linda Buck and Richard Axel, joint 2004 Nobel laureates in Medicine. The OR7D4 receptor governs perception of androstenone, and OR5A1 governs perception of beta-ionone. A single amino acid substitution is enough to flip a person from sensitive to anosmic.
Perfumery implications
A fragrance heavily built on Galaxolide musks may smell weak or as if the base were missing to a selectively anosmic evaluator, even when it works fully for the rest of the audience. Fragrance houses such as IFF exclude anosmic evaluators from their panels for the materials concerned. Olfactive fatigue is a different phenomenon, temporary and exposure related, whereas selective anosmia is permanent and genetic. The question also arises with historical animalic musks such as tonkin musk.
Sources
- Wikipedia, Specific anosmia (accessed 4 June 2026)
- Keller A. et al., Genetic variation in a human odorant receptor alters odour perception, Nature, 2007 (accessed 4 June 2026)
- Nobel Prize, Linda B. Buck and Richard Axel, Medicine 2004 (accessed 4 June 2026)
- Wikipedia, Androstenone (accessed 4 June 2026)