Illustration by Caroline Casey
by Gabrielle Kassel
Ever walk onto a subway or into a bar and feel immediately, alarmingly drawn to someone?
Women’s health experts and endocrinologists say it may come down to pheromones. When we feel a “heightened sexual response,” says endocrinologist and internal medicine specialist Dr. Elena A Christofides, we might be “receiving messages from the pheromones of all those sweaty people.”
You’ve likely heard the word “pheromone,” but you may not know what it is or how it affects attraction. Here’s everything you need to know—from what they are (and aren’t) to how they affect mating, and how we may be interfering with our pheromones’ natural communication abilities.
What Are Pheromones?
Pheromones are invisible chemicals that animals, including humans, emit into the environment and affect the behavior of others within the same species.
There’s a misconception that pheromones are synonymous with scent. “It’s more subtle than ‘That person smells nice, I must be compatible with them,” Dr. Christofides says. “It’s more of an innate detection than smell.”
Pheromones are also often confused with hormones. They’re linguistically similar because they’re complementary compounds, according to Dr. Felice Gersh, author of PCOS SOS: A Gynecologist’s Lifeline To Naturally Restore Your Rhythms, Hormones and Happiness. But there are subtle differences. For starters, hormones are made out of amino acids (proteins), while pheromones are made of lipids (fats). Also, “hormones are meant to control and regulate different functions within the body. Pheromones, on the other hand, send a message outside the body,” she says. Basically, my hormones affect me, while my pheromones affect you.
What message are they sending, exactly? According to Dr. Gersh, “they could be sending warning signs, mating invites, or, parents and their offspring, bonding agents.” Dr. Christofides adds that these messages flag our hormonal status, or where we are in our cycles, to potential mates in order to trigger sexual behavior.
How Do Pheromones Affect Humans?
While pheromones are well-researched in animals, human-specific research is very limited. In fact, it wasn’t until 30 years ago that the first study found that humans probably have pheromones, too.
Dr. Gersh and Dr. Christofides both believe humans have pheromones, and that those pheromones operate in a similar way to other animals. “It’s speculation, but it’s rational speculation,” says Dr. Gersh. “In other species, we know that there is something about pheromones that creates sexual desire. Humans are not worlds apart from other animals. We're part of the animal kingdom.”
For animals, pheromone detection and compatibility is part of the proper mating selection process, says Dr. Christofides. One study found that when female hamsters are fertile, they release pheromones that are detectable by male hamsters and compel them to mount and mate with the female. Anecdotally, Dr. Christofides says that when she’s ovulating, her husband reports feeling more drawn to her sexually, which she hypothesizes is similarly related to pheromones.
"Humans are not worlds apart from other animals. We're part of the animal kingdom."
Of course, it’s not that our pheromones are attracting everyone. Rather, we may be attracting the folks most genetically different from us—in particular, a certain type of immune system gene called MHC (major histocompatibility locus). There was a famous “sweaty T-shirt” study in which a scientist gave men a clean T-shirt to wear for two days and nights before returning the now-dirtied shirt back. Then, the scientist put each shirt in a box equipped with a “smelling hole” and had female volunteers come in and sniff the boxes, and record the odors desirability. The results? The women, overall, preferred the scents of T-shirts worn by men whose MHC genes were different from their own.
However, Dr. Christofides adds, “the women in that particular study weren’t on oral contraceptives.” Why would that matter? Read on.
Turning Off The Turn-On?
Dr. Gersh and Dr. Christofides hypothesize that hormonal birth control—which tens of millions of women use—could be interfering with the natural mating process.
Dr. Gersh explains these contraceptives “manipulate female hormones,” which may affect their pheromones, since the two work together to help animals mate effectively. Research has found that when women are on birth control, they may pick partners that are more MHC-similar. Some researchers have speculated that this is related to hormonal birth control elevating progesterone levels and stopping ovulation—meaning, it tricks the body into thinking it’s pregnant. When you’re pregnant, according to Dr. Gersh, “you naturally seek out connection and protection from family members, and that means genetic similarity.”
Of course, that doesn’t mean we should abandon hormonal birth control—for millions of women, it’s been great option for preventing pregnancy, controlling symptoms associated with polycystic ovary syndrome and endometriosis, reducing cramps, improving acne, and offering vulva-owners an incredible amount of sexual freedom and bodily autonomy.
Besides, many scientists or health experts aren’t convinced of the power of pheromones. In an article for Splinter on the topic, Richard Benton, an associate professor at the Center for Integrative Genomics in Switzerland who has previously studied pheromones says, "In humans there is very limited evidence that we use pheromones to attract members of the opposite sex,” and that “there is some doubt as to whether humans can detect pheromones, as we lack a functional version of the sensory organ that other mammals use.” Basically, he says, even if humans have pheromones, there’s not enough evidence to believe it they’re detectable or that they play a role role in our mating habits.
Is There Anything We Can Do To Optimize Our Pheromones?
Again, there’s not much research on how our pheromones work in humans, so there’s no proven ways to enhance our pheromones. But for people who are curious, Dr. Gersh and Dr. Christofides suggest considering non-hormonal birth control and non-scented beauty and hygiene products. “When we smother our lives with external chemical-laden scents that don’t belong,” says Dr. Christofides, “we could be disrupting others ability to detect our natural, phermonal scent.”
Even though not everyone believes these theories, ultimately Dr. Gersh and Dr. Christofides just want to shed more light on the topic. “As humans, we could be playing with fire here,” says Dr. Gersh. “But we really can’t say because there’s not enough research on pheromones.”
Gabrielle Kassel is a New York-based sex and wellness writer and CrossFit Level 1 Trainer. When she’s not testing sex toys, Tindering in public, or asking folks about their sex lives (all in the name of journalism, of course) she can be found reading self-help books, bench-pressing, or pole dancing.