How OR6A2 Gene Influences How People Perceive Cilantro's Smell

Cilantro, the green leaves and stems of the Coriandrum sativum plant, is one of the most interesting and divisive ingredients in the culinary world. While some people enjoy its fresh, citrusy flavor, others find it unpleasant with an unmistakable soapy smell. This is not just a matter of preference; according to published data, between 3% and 21% of the population is genetically predisposed to perceive cilantro as soapy (Clinic, 2025).

Figure 1. A bowl of cilantro ready to be cut (“Is There a ‘Cilantro Soap Gene’?”, 2025)

How the Human Nose Detects Odors

The human nose detects odors when airborne molecules enter the nasal cavity, where odorants, or volatile compounds that stimulate olfactory sensations, dissolve in mucus and bind to specialized olfactory receptors, encoded by a large family of Olfactory Receptor (OR) genes. Specific odorants fit into corresponding receptors like a lock and a key. Stimulation of ORs converts the chemical information encoded in odorants into corresponding neuronal action potentials that depolarize olfactory sensory neurons, thereby sending signals to different parts of the brain for processing (Sharma et al., 2018).

Figure 2. A schematic illustrating the functions of odor receptors, which are encoded by odor receptor genes (Moon, 2020).

The Chemistry Behind Cilantro’s Flavor

Cilantro owes its polarizing odor primarily to volatile organic compounds (VOCs) naturally present in the plant, with aldehydes making up the dominant class. Key compounds identified in cilantro include (E)-2-decenal, decanal, (E)-2-dodecenal, and (E)-2-tetradecenal (Kumar et al., 2022). Notably, these same aldehydes are also commonly found in detergents and soaps. While these odorant molecules define the plant’s distinctive aroma, the perception of their odor, whether they smell “fresh” or “soap-like,” depends heavily on the consumer’s genetic makeup.

The Role of the OR6A2 Gene in Cilantro Sensitivity

To be more specific, sensitivity to these aldehydes has been traced to a mutation in OR6A2, an olfactory receptor gene located on chromosome 11 (Callaway, 2012). In a genome-wide association study (GWAS) of 14,604 participants of European ancestry who reported whether cilantro tasted soapy, researchers identified a significant correlation between the perceived “soapy” flavor of cilantro and a single-nucleotide polymorphism (SNP), which refers to the genetic variation that represents a difference in a single nucleotide at a specific position in the genome. This SNP (rs7291001) occurs within the OR6A2 gene, which exhibits high binding specificity for several aldehydes, including those present in cilantro. As a result, individuals with this genetic variant are “biologically programmed” to detect the cilantro’s odor as soapy and detergent-like. Nonetheless, it is important to note that this SNP only has a low heritability rate of 0.087, suggesting there may be other factors contributing to this sensory puzzle (Eriksson et al., 2012).

Figure 3. A visual map detailing the moment the aldehyde is bound to the odorant receptors until it is perceived by the brain. (Smart, 2023).

Key Takeaways

Cilantro’s reputation as a herb with a polarizing smell is a perfect example of how genetics, chemistry, and sensory biology collide to shape our unique experience of the world. Studies have revealed that the soap-like odor of this plant is actually linked to an SNP in the OR6A2 olfactory receptor gene, which increases individuals’ sensitivity to certain aldehydes present in the plant. However, given the low heritability rate of this mutation, other factors may also be affecting individuals’ preferences for cilantro.

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References

1. Callaway, E. (2012). Soapy taste of coriander linked to genetic variants. Nature. https://doi.org/10.1038/nature.2012.11398

2. Clinic, C. (2025, August 25). Can a gene cause cilantro to taste like soap? Cleveland Clinic. https://health.clevelandclinic.org/do-you-love-or-hate-cilantro-the-reason-may-surprise-you

3. Eriksson, N., Wu, S., Do, C. B., Kiefer, A. K., Tung, J. Y., Mountain, J. L., Hinds, D. A., & Francke, U. (2012). A genetic variant near olfactory receptor genes influences cilantro preference. arXiv (Cornell University). https://doi.org/10.48550/arxiv.1209.2096

4. Is There a ‘Cilantro Soap Gene’? (2025, August 25). Cleveland Clinic. https://health.clevelandclinic.org/do-you-love-or-hate-cilantro-the-reason-may-surprise-you

5. Kumar, S., Ahmad, R., Saeed, S., Azeem, M., Mozūraitis, R., Borg-Karlson, A., & Zhu, G. (2022). Chemical composition of fresh leaves headspace aroma and essential oils of four coriander cultivars. Frontiers in Plant Science, 13, 820644. https://doi.org/10.3389/fpls.2022.820644

6. Moon, D. (2020, October 16). Odor Receptor Genes: Smelling things differently. Genetic Lifehacks. https://www.geneticlifehacks.com/intriguing-genes-differences-in-how-we-smell-things/

7. Sharma, A., Kumar, R., Aier, I., Semwal, R., Tyagi, P., & Varadwaj, P. (2018). Sense of Smell: Structural, functional, mechanistic advancements and challenges in human olfactory research. Current Neuropharmacology, 17(9), 891–911. https://doi.org/10.2174/1570159x17666181206095626

8. Smart, K. (2023, November 8). a Morsel of Science: Why Some People Find Cilantro Soapy | by a Morsel of Science | Medium. Medium. https://medium.com/@a.morsel.of.science/a-morsel-of-science-why-do-some-people-find-cilantro-soapy-ab726801c212

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