Say the word "pheromones" and what springs to mind is usually perfume, or some chemical key to attracting the opposite sex. But do you actually know what pheromones really are? If you're curious, give me three minutes — with examples from the animal kingdom and studies on humans, let's bust the myths around pheromones together!
Pheromones?
Pheromones are a family of chemicals that living things release outside their bodies. Contrary to what most people assume, pheromones aren't only about finding a mate — they can also be used to warn fellow members of a species, to mark where food is, to call companions when needed, and more. Among insects, pheromones are one of the most commonly used means of communication: the way ants can line up in such an orderly column is precisely thanks to pheromones. Of course, humans aren't insects, so if we want to study human pheromones, we certainly can't rely on findings from insects alone. So do mammals have pheromones too?
The answer is yes! Pig farmers use androstenone to test whether a sow is in her ovulation period and ready for artificial insemination. There is also a research team (Ishii et al., 2017) that used genetic techniques to test a mouse pheromone called Exocrine Gland-Secreting Peptide 1 (ESP1), and found that ESP1 can heighten sexual desire in female mice. Whether in structurally simpler insects or in more evolutionarily advanced mammals, we have evidence supporting the existence of pheromones — and these pheromones are linked to sex, which seems to give us reason to believe human pheromones do their work too. But before we draw any conclusion, let's first take a look at studies that focus on humans!
Studies on Human Pheromones
A 2008 study (Saxton et al., 2008) found that at a speed-dating event, women who had inhaled androstadienone — a chemical thought to be a male pheromone — rated men as more attractive than the control group did. In a medical review article, Mostafa et al. (2012) drew on the results of several studies to propose that both androstenone and androstenol could be human sex pheromones. Although the review leaned towards supporting the existence of pheromones, the team pointed out that most of the studies, owing to issues such as experimental design, did not necessarily provide strong, compelling evidence. In 2017, a team (Hare et al., 2017) studied two candidate human pheromones, abbreviated AND (the progesterone derivative 4,16-androstadien-3-one) and EST (estratetraenol). The team asked three questions: whether AND and EST would make people perceive faces with no obvious sex-specific features as belonging to the opposite sex; whether they would make people find the opposite sex more attractive in the short term; and whether they would make people more prone to unfaithfulness. The results showed that AND and EST had no significant effect in any of these respects, negating their role as human pheromones. All in all, scholars across disciplines have reached differing conclusions on whether human pheromones exist, and for now the academic community still has no consensus.
So do humans choose their partners by smell? The answer is yes — though the mechanism involved isn't necessarily just pheromones. In a classic study known as the "sweaty T-shirt study", a research team collected a large number of T-shirts that men had worn for two days straight, soaked in male sweat, and then had women choose which T-shirt's scent they found most attractive. By analysing the genes of both the men and the women, the team found that the men a woman chose mostly had a different MHC (Major Histocompatibility Complex) from her own. The MHC in our genes determines an individual's immunity, and if parents have different MHCs, their offspring will have stronger immunity. MHC is not a pheromone — it is closer to the concept of a fingerprint. Each person's MHC is not necessarily the same, which makes it hard to boost your own attractiveness through external means (such as perfume). From this we can see that humans may genuinely use body scent to seek out the partner best suited to them — but this is not quite the same as the concept of pheromones.
In Closing
So does that mean the pheromone perfumes on the market don't work? Does that mean our body scent has nothing to do with finding a mate? Of course not! Body scent absolutely has something to do with personal image. Even though science has yet to fully confirm the existence and effects of pheromones, scent still makes people think of things like style and tidiness. So using the right products to improve our scent will surely help, both in how we relate to others and in how we come across. As for whether it has anything to do with pheromones — we'll leave that for you to decide.
References
Hare, R. M., Schlatter, S., Rhodes, G., & Simmons, L. W. (2017). Putative sex-specific human pheromones do not affect gender perception, attractiveness ratings or unfaithfulness judgements of opposite sex faces. Royal Society Open Science, 4(3), 160831. https://royalsocietypublishing.org/doi/full/10.1098/rsos.160831
Ishii, K. K., Osakada, T., Mori, H., …, Yoshihara, Y., Miyamichi, K., & Touhara, K. (2017). A labelled-line neural circuit for pheromone-mediated sexual behaviors in mice. Neuron, 95(1), 123-137. https://www.cell.com/action/showMethods?pii=S0896-6273%2817%2930476-2#%20
Mostafa, T., Khouly, G. E., & Hassan, A. (2012). Pheromones in sex and reproduction: Do they have a role in humans? Journal of Advanced Research, 3(1), 1-9. https://www.sciencedirect.com/science/article/pii/S2090123211000397#!
Saxton, T. K., Lyndon, A., Little, A. C., & Roberts, S. C. (2008). Evidence that androstadienone, a putative human chemosignal, modulates women’s attributions of men’s attractiveness. Hormones and Behavior, 54(5), 597-601. https://www.sciencedirect.com/science/article/abs/pii/S0018506X08001864?via%3Dihub
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