Hormones and Attraction: What the Science Shows

A man turns forty five and starts testosterone replacement, half expecting his jaw to sharpen and his brow to thicken. It never happens. The bones of his face finished their one chance to be shaped by hormones back in puberty, and no adult dose can call them back for a rewrite. That small, stubborn fact is the spine of this episode: hormones build a great deal of what we find attractive, but they do most of that building early, once, and then they stop. What is left, once puberty closes the account, is something much more interesting than a hormone panel.

The familiar story goes like this: testosterone and estrogen do not just run libido, bone density, and reproduction. During development, especially puberty, they also sculpt the traits that read as male or female at a glance, things like facial structure, voice, muscle, fat distribution, skin, and hair (01:39). From there it is a short step to a tidier, more seductive claim, the one behind countless magazine headlines: that a masculine face is basically a testosterone readout, and that women are wired to chase that readout hardest when they are most fertile. This is the ovulatory shift hypothesis, the idea that female preference for masculine-looking men spikes specifically around ovulation, as a kind of evolved genetic quality filter. It has the clean shape of a good evolutionary story. It has not held up well.

When researchers moved from small, one-time surveys to larger studies that measured the same women's hormones repeatedly over time, instead of guessing at cycle phase from a calendar, the ovulatory shift became very hard to reproduce (02:37, 03:07). Preferences for masculine faces turned out to be inconsistent across studies, sometimes present, sometimes context dependent, sometimes absent entirely (08:09). That does not mean reproductive hormones are irrelevant to attraction, they clearly shape libido and sexual motivation. It means the specific, popular version of the story, that a hormone threshold flips a switch and jawlines suddenly matter more, is not supported by the data.

The deeper problem is with the premise itself: that a masculine face is a live readout of a man's current testosterone. A study by researchers named Pound and colleagues tested this directly and did not find the simple relationship everyone assumes, that men with more masculine faces simply run hotter on baseline testosterone (05:09). What they found instead was odder and more useful: men with more masculine faces showed a larger testosterone surge after winning a competition, which points to a dynamic, responsive hormonal system rather than a fixed dial (05:40). A masculine face, in other words, may say something about how a person's development went. It says very little about what is circulating in their blood this afternoon.

"Your face is not a hormone panel." — Gabrielle Lyon [04:40]

Lyon pushes the point further with a thought experiment: take two fifteen year old boys. One matures earlier, grows bigger and stronger, and because of that gets picked for sports, then trains for years, accumulating skill and muscle on top of his head start. By adulthood, what a doctor sees in him is not simply hormones, it is selection, puberty, genetics, hormones, training, and years of choices, all stacked together (06:41). This is the difference between genotype, the inherited genetic blueprint a person is born with, and phenotype, the physical result of that blueprint interacting with behavior and environment (07:14). A muscular man might have ordinary testosterone and a decade of consistent training. Another man might have higher testosterone and have never lifted a weight in his life. They will not look the same.

"A masculine face may tell you something about a person's developmental history. It doesn't tell you his or her testosterone today." — Gabrielle Lyon [06:09]

Strength Beats the Jawline

If the face is such an unreliable gauge, what actually predicts attraction? A meta-analysis in the journal eLife looked at masculine traits against real mating and reproductive outcomes and found that strength and muscularity were the traits consistently tied to men's mating success, while facial masculinity was not nearly as consistent a predictor (09:37, 10:08). A separate study in Royal Society Open Science, led by a researcher named Aaron Sell, showed women photographs of men's bodies and asked them to rate attractiveness. Perceived physical strength alone explained 70 percent of the variance in how women rated male physical attractiveness (11:10). Height and leanness added another 10 percent, bringing the total to roughly 80 percent explained by just those three visible traits. Notably, the relationship was linear: there was no point at which a body read as "too muscular" to raters, stronger kept scoring higher across the board (11:10).

It is worth being precise about what that 80 percent does and does not mean. This is body attractiveness under experimental conditions, a snapshot judgment from a photo. It says nothing about who someone falls in love with, marries, or builds a life with, and nothing about intelligence, loyalty, or kindness (11:41). But as a pure visual signal, strength carries enormous weight, far more than bone structure.

There is a plausible evolutionary reason for that. In ancestral environments, physical strength was tied directly to a man's ability to hunt, defend resources, and protect a mate and offspring (12:05). Building and holding muscle also requires a well-functioning immune system and an efficient metabolism, which makes a strong body a hard to fake signal of underlying health, the kind of thing that is difficult to counterfeit with grooming or clothing (12:59). Strong individuals were also more likely to win status contests within a group, which historically meant better resources for a family. None of this requires knowing anyone's lab values. It only requires looking at what a body can do.

What Estrogen Leaves Behind

Women's biology gets a parallel treatment. One classic study found that women with higher measured estrogen were rated as more feminine, attractive, and healthy looking (13:56). But that correlation does not let anyone reverse engineer a number from a photo, and raising estrogen artificially will not make someone more attractive, because biology does not work like a volume knob.

"Hormones are not a volume knob you turn up for better results." — Gabrielle Lyon [14:20]

Culture is the other variable that quietly undercuts any hormone-as-destiny story. If estrogen simply dictated beauty, beauty standards would not move. They move constantly, from the softer, fuller bodies Renaissance painters favored to the thin ideal of parts of the twentieth century to the athletic, visibly muscular standard gaining ground now (14:42, 15:16). Biology sets raw material. Culture argues about what to do with it.

Where estrogen's fingerprints are easiest to see is in tissue most people never think of as hormone-responsive: skin. Estrogen receptors sit throughout skin and connective tissue, and estrogen affects collagen, hydration, thickness, and blood flow (15:44). When estrogen drops at menopause, women can lose on the order of 30 percent of their skin collagen within the first five years, which shows up as thinner, drier, less elastic skin and more visible wrinkling and bruising (16:08). Menopausal hormone therapy can improve some of those collagen and thickness measures, though that is one factor among several, including symptoms, age, and medical history, in a decision made with a clinician (16:08, 16:36).

The thread running under all of it is agency. Skeletal structure, facial maturation, and voice are hormone-built traits locked in during puberty and are not up for renegotiation in adulthood. Skin changes with estrogen whether or not anyone chooses it. Muscle is different. It is shaped by the same endocrine system, yet it stays negotiable for an entire lifetime.

"Of everything hormones build, muscle is the organ system you can both see and change." — Gabrielle Lyon [17:07]

That is the real argument of the episode, dressed up as a myth-busting tour through testosterone and jawlines. People cannot read anyone's hormone numbers off a face or off skin. What they are seeing, always, is a phenotype, a lifetime of genetics, development, environment, and behavior compressed into one visible body (17:07). Strength happens to be the part of that body still being written. It is visible, it is trainable, and according to the data here, it is also the trait most consistently tied to how attractive a body reads to someone else. The jaw is fixed by puberty. The deadlift is not.