Why are men actually going bald?

Testosterone is just a performer, but the real cause is in the genes

When a man notices the first signs of baldness, he often hears one explanation: “it’s due to testosterone.” And while there is a grain of truth in that, it’s like saying that rain falls “through the clouds.” Testosterone is merely a tool, a biochemical executor of a genetic program written into our DNA millions of years ago.

But why would evolution deprive us of our hair? Is baldness a mistake of nature, or a hidden asset that helped our ancestors survive?

The paradox of androgenetic alopecia

Androgenetic alopecia (AGA, androgenetic alopecia) affects about 50% of men before the age of 50. It is the most common cause of hair loss in men, and one of the most enigmatic features of our species.

How does it work at the cellular level?

Dihydrotestosterone (DHT), a derivative of testosterone and its active form, binds to receptors in hair follicles in the scalp. In men genetically predisposed to baldness, this causes the follicles to miniaturize: hair becomes thinner, grows shorter, and eventually stops growing. But this is just a mechanism. The real question is: why did our genes tell testosterone to have such an effect on hair?

Theory 1: Signal social maturity

A study published in Social Psychological and Personality Science found that balding men are perceived as older (by an average of 4 years), more dominant and socially stronger. In the hierarchical structures of our ancestors, baldness may have been a visual signal of maturity and readiness for leadership roles. Just as a silver back in gorillas indicates a dominant male.

Anthropologist Frank Muscarella pointed out that baldness in men typically occurs after they reach childbearing age, but before they leave the social scene. This suggests that it is not simply “wear and tear” on the body, but a planned change. In hunter-gatherer societies, where the experience and wisdom of older members of the community were crucial to the group’s survival, visual signs of maturity may have actually increased an individual’s prestige and influence.

Theory 2: Thermoregulatory Advantage

This theory links baldness to better adaptation to intense exercise. How would this work? Studies show that a bald head loses heat 20-30% more efficiently than one covered with thick hair. Less hair on the top of the head allows the body to dissipate heat faster. This gives more efficient thermoregulation during hunting and reduces the risk of overheating in savanna conditions. And a man fitter and more resilient for hunting (bringing food) was more attractive as a father of children – he could ensure survival.

Of course, this theory begs the question: so why did women keep their hair? Probably because of sexual selection. Long, healthy hair in women has signaled health, youth and fertility for millennia. Evolution can promote different traits in both sexes in opposite directions if each brings an adaptive advantage in its context.

Theory 3: Protection from parasites and diseases

Paradoxically, in a prehistoric context, less hair may have meant fewer health problems. Lice was a serious problem in communities before the invention of soap and regular hygiene. A bald head meant less risk of lice infestation, easier identification of wounds and skin problems, and a reduction in harboring sites for disease-carrying fleas and ticks.

Some research suggests that all of the loss of body hair in Homo sapiens, including gradual baldness of the head in parts of the population, may have been an evolutionary response to pressure from external parasites. In a world where parasite-induced infections could be fatal, any adaptation that reduced this risk provided a significant survival advantage.

Theory 4: Baldness as a costly signal of genetic quality

The most intriguing hypothesis comes from evolutionary biology and concerns a concept called the “costly signal principle.” According to this theory, baldness can act as a high genetic signal precisely because it is unfavorable. Hair loss makes men more vulnerable to UV radiation, cold weather and minor head trauma. Surviving and reproducing despite this “costly appearance” may signal to female partners that the individual has such high genetic quality in other areas that he can afford this “disadvantage.”

It is a similar mechanism to the peacock’s tail. It is beautiful, impractical and makes it difficult to escape from predators. Its existence says: “I am strong and healthy enough to survive despite this burden.” Baldness may have served an analogous function in human societies. A man who achieved high social standing and lived to have offspring despite baldness must have had other strong genetic assets.

What do the genetic tests say?

Modern genetics is shedding new light on this evolutionary speculation. As many as two hundred and eighty-seven different sites in the human genome associated with androgenetic alopecia have been identified. This confirms that androgenetic alopecia is a polygenic trait, dependent on the interaction of many genes, not just one “baldness gene.” Fascinatingly, most of these genes are located on chromosomes not directly linked to sex. The strongest genetic marker is the androgen receptor located on the X chromosome, which men inherit exclusively from their mothers. This explains why it is often said to look at the mother’s father to predict one’s own risk of baldness.

A key observation from genetic studies is this: the same genetic variants that predispose to baldness often correlate with higher testosterone levels, better bone density and increased muscle mass. This suggests that baldness may be a specific side effect of genes conferring an adaptive advantage. Evolution does not optimize each trait individually, but the overall reproductive success of the organism.

The theory of antagonistic equilibrium

A concept called “antagonistic pleiotropy” in evolutionary biology offers an elegant explanation for why baldness genes survive in a population despite an apparent defect. Pleiotropy refers to a situation in which the same gene affects many different traits in an organism. Antagonistic pleiotropy occurs when a gene has a positive effect in one lifetime or context and a negative effect in another.

In the case of baldness, the theory goes as follows: The same genetic variants that increase physical strength, social dominance and reproductive success through high levels of androgens in youth, cause hair loss in middle age. It’s a classic evolutionary trade-off. From a Darwinian perspective, what matters most are genes that maximize reproductive success during a crucial period, roughly between the ages of twenty and thirty-five. If the same genes cause baldness in one’s thirties or forties, when a man is likely to have already reproduced, evolution is “indifferent” to it.

A study published in Biology Letters found that men with higher testosterone levels achieve significantly greater reproductive success in their twenties to thirties, but at the same time have a higher risk of baldness after age thirty-five. This perfectly illustrates the mechanism of antagonistic pleiotropy in action.

ALSO READ: “Why does baldness seem unattractive today? The conflict between evolution and culture “

Why are men actually going bald?

The answer, as is often the case in biology, is multi-layered and complex. At the level of the executive mechanism, we know that dihydrotestosterone acts on genetically vulnerable hair follicles, causing their gradual miniaturization. This is the answer to the “how” question.

At the genetic level, we see that polymorphisms in hundreds of genes are responsible for baldness, particularly within the androgen receptor and steroid hormone metabolism pathways. This answers the question of “what” exactly in our DNA determines baldness.

But at the evolutionary level, answering the “why” question, the truth is most likely a synthesis of all the theories presented. Baldness may be simultaneously a signal of social maturity, a side effect of genes that increase fitness and testosterone levels, a possible thermoregulatory advantage, and a costly signal of genetic quality. These mechanisms are not mutually exclusive, but may work synergistically, each in a slightly different context and population.

The most important conclusion is this: baldness is not a genetic “mistake” or a “disease” in the evolutionary sense. It is a trait that has co-evolved with other favorable genetic traits over millions of years and has therefore survived in the gene pool of our species. Our genes do not “make a mistake” when they deprive some men of their hair. They are simply carrying out an ancient program that once, in a different context, made evolutionary sense. It’s a trait that co-evolves with other genetically advantageous characteristics.

What does this mean for modern men?

Understanding the evolutionary roots of baldness does not change the fact that in the twenty-first century it can affect self-esteem and psychological comfort. We live in a world that is significantly different from the environment in which our genes evolved. Adaptations that may have been beneficial on the savannah a hundred thousand years ago do not necessarily fit modern social and aesthetic realities.

At Kierach Medical Clinic, we understand that genetics do not determine your choices about your body and appearance. Modern medicine offers solutions that our ancestors did not have. The decision to intervene, whether pharmacologically or surgically in the form of a hair transplant, is personal and fully justified. A hair transplant is not a fight against nature, but a conscious choice made in a world where we have more control over our own bodies than at any time in human history.

Evolution gave us baldness genes for specific reasons that made sense thousands of years ago. But we, as a species endowed with consciousness and medical technology, can consciously decide which evolutionary legacies we want to keep and which to modify according to our own preferences and values.

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