What causes men to lose their hair? It isn’t just genetics. A combination of factors actually cause baldness.
The Genetics of Hair Loss in Men
The most common type of baldness, which is called Male Pattern Baldness or Androgenetic Alopecia, is directly caused by inherited genes, and those genes can come from either parent. This is in direct contradiction to the commonly held belief that baldness is only inherited from the mother, although genes from the mother do seem to cause baldness more often.
Since it’s a very complex process, we still have more to learn about how baldness is inherited, but the consensus now is that more than one gene is involved. We just don’t yet know what any of these genes are; they have yet to be identified.
Some men carry the genes for baldness but do not become bald. When the gene actually “expresses” itself, it’s called “expressivity.” This is where nurture, rather than just nature, may become involved in whether someone suffers hair loss. Stress, age, and hormones come into play.
For this reason, a man can be in a family of men who are bald and have minimal hair loss himself because his genes are not expressing due to a variety of factors. Another man might be in a family of men who have the genes but no expression, while he finds himself experiencing substantial hair loss – again, due to a variety of factors affecting gene expression.
Hormones and Hair Loss
Like women, the male body produces many different hormones that work within the endocrine system and affect all of the body’s other systems. Testosterone is the major male sex hormone. It’s responsible for puberty, the deep male voice, the muscular male body, and facial and body hair growth.
The relationship between testosterone and hair loss/growth was discovered in the early part of the 20th century when psychiatry treated mental illness through castration, which seemed to calm aggression in the male patients. One of the physicians discovered that a mentally ill twin had a full head of hair, while the mentally healthy twin was bald. The doctor injected the mentally ill twin with testosterone, and the patient went bald like his brother. When he stopped giving the patient the testosterone, the hair loss was slowed, but the dead hair follicles remained dead.
The belief is that a type of testosterone is what greatly affects male pattern baldness. This hormone is called DHT – dihydrotestosterone, which is created when an enzyme called 5-a reductase acts on testosterone. DHT then causes the growing cycle of the hair to decrease and the resting phase of the hair growth to increase. As a result of this, the amount of hair reduces with each hair growth cycle.
The hair follicles that are susceptible to this activity are generally on the front and top of the head rather than the back. This is why there is a pattern to hair loss. The hair that is not susceptible is called “permanent.” This is where donor hair is taken for hair restoration procedures. The amount of permanent hair varies by person. Some men have a large area of permanent hair, and others have less.
The right genes and the right hormone activity may or may not cause baldness. The hair follicles that are susceptible to loss must be continually exposed to the hormone activity in order for the hair loss to occur.
Hair loss also occurs in cycles that are not fully understood. Some men may find that they stop losing their hair for a period of time, but it may begin again later.
Age and Hair Loss
The activity that causes hair loss takes time, and this varies from one man to another. So, hair loss begins at different ages depending on the man. In some cases, this hair loss can start as early as 20 years old, but in most, this hair loss starts around 30-35 years old and progresses over time. The factors involved are complicated, involving testosterone levels and the specific genetics of the man.
While we’re still learning about the intricacies of hair loss, it’s clear that as a man ages, he will lose more hair. This occurs even in men who have no genetic male pattern baldness. Some hairs even shrink or “miniaturize,” becoming finer. For most men, however, there is enough permanent hair even in their 70’s for hair restoration procedures to be effective.
Stages of Balding
The Norwood Scale is used to determine the degree of balding that has occurred.
There is a seeming stepwise progression in this classification, but men do not necessarily progress through this pattern. Some men fall into the A-Variant of hair loss, in which the hair loss is more pronounced on the frontal area of the scalp.
How Much Hair Do I Need?
Although an in-person exam is necessary for a real plan for surgical hair restoration, here are some general guidelines on the amount of hair that you might need to restore different classifications of hair loss.
The number of grafts that can be safely harvested will depend on your hair and follicular unit density. Using the FUE method, we can harvest up to about 15% of the hair from the back of the head. We only use hair from the back of the head – hair that will be protected from future hair loss. It is not unusual to be able to harvest and graft up to 3000 units during one sitting using the NeoGraft® machine. Sometimes, people with Type 6 or 7 hair loss may need another procedure, but that is not the norm.