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What is Genetic Hair Loss?

The Biology of Hair Loss
Genetic male and female pattern hair loss is also called androgenetic alopecia (AGA). The word androgenetic represents how both androgens (andro) and genes (genetic) are involved in hereditary hair loss. Alopecia is the medical term for hair loss. It comes from the Ancient Greek word ”αλωπεκια” which means "without hair".

Continue reading to learn more about the prevalence, causes, symptoms
and treatment options for genetic hair loss.

Prevalence of Androgenetic Alopecia in Men and Women

Androgenetic alopecia (sometimes spelled as androgenic alopecia) is one of the most common causes of hair loss throughout the world. 

It is estimated that around 40% of men will suffer from some degree of male pattern baldness by the time they reach the age of 35. This rate continues to increase with age. Approximately 50% of men over the age of 50 have noticeable hair loss. This increases to 65% by the age of 60 and 80% by the age of 80.

Although perhaps not spoken about as often, the numbers for women are high, too. Female pattern baldness affects approximately 40% of women by the age of 50 and 55% of women over the age of 70.

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The Biology of Hair Loss

There are many different types of hair loss — from female and male pattern baldness to cicatricial alopecia. These conditions are all unique and, as such, have different causes, symptoms, and treatment options. Below is some key information about the biology of androgenetic alopecia.

What Causes Androgenetic Alopecia?

Androgenetic alopecia is an inherited condition that usually results in permanent hair loss. It is associated with the presence of multiple genes, as well as dihydrotestosterone (DHT) — a hormone with powerful androgenic properties.

In humans, testosterone is secreted primarily by the testicles of males and, to a lesser extent, the ovaries of females. On average, testosterone levels are about seven to eight times greater in adult males than in adult females. However, females are much more sensitive to the hormone. The 5-Alpha reductase enzyme works to convert testosterone into DHT. 

Both biological males and females also have hormones called androgens. Besides playing a key role in normal male sexual development, these hormones are responsible for regulating hair follicle size via the androgen receptor gene. This process takes place when DHT binds to androgen receptors in dermal papilla cells. 

However, the presence of DHT alone will not cause hair loss in individuals with no genetic predisposition. You might then wonder, “How exactly is hair loss hereditary?” The answer is simple — the genes for AGA must be present, too. These specific genes for hair loss make scalp hair follicles extraordinarily sensitive to DHT, resulting in an increased risk of female or male pattern hair loss. 

The combination of DHT and specific genes will progressively shrink the hair follicles and shorten their life cycle. This will cause hair to grow out looking thinner and more brittle. It will also make it fall out faster, resulting in progressive hair loss.  

Inheritance Patterns of Androgenetic Alopecia

You know now the biology behind AGA. However, it is still important to investigate the question, “How is alopecia hereditary? Every type of hair loss has a unique inheritance pattern that is dependent on complex factors such as genetic variation. 

Androgenetic alopecia has a polygenic inheritance pattern involving multiple genes. In fact, a novel study revealed more than 250 different genetic locations associated with severe hair loss. This is the most extensive genome-wide study of baldness to date, using data from over 52,000 male participants in the UK Biobank study. 

Biological sex is determined by X and Y chromosomes. Everyone has at least one X chromosome, and it is here that the AR gene is found. Biological males inherit their X chromosome from their mothers. 

This means that the genetics on the maternal side of your family play a big role in determining your genetic predisposition to AGA. However, there are also various other hair loss genes that influence baldness. These are present on non-sex chromosomes (autosomes) and can be inherited from either parent. 

Patterns of inheritance of the AGA genes can sometimes be unpredictable. Having a father or uncle with AGA makes it probable — but not certain — that AGA will occur in a son or daughter. When it comes to genetic alopecia in females, there may not be an apparent hereditary association. Whereas a man with AGA usually has close male relatives with AGA, no such family pattern may be evident for women. 

These patterns make it difficult to accurately predict whether someone will experience female or male pattern baldness. Rather, it is advised to monitor your hair loss and, if it exceeds a normal range, to visit a healthcare professional. 

Are you worried about developing genetic baldness or another hair loss condition? Get in touch with our Glasgow hair restoration clinic for more information, or book an appointment with Dr Bonaros for expert advice. 

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Symptoms of Androgenetic Alopecia

Having androgen receptors with high sensitivity levels to DHT will eventually cause your hair follicles to either stop producing hair or produce only miniaturised “peach fuzz” hair. While this biological process is the same for everyone, the resulting hair loss usually manifests differently for men and women. 

Men will usually notice the start of hereditary hair loss above their temples. This receding hairline creates a distinct M-like shape and is combined with hair thinning on the crown. Male androgenetic alopecia is especially visible with shorter hairstyles and can often result in complete baldness. 

Genetic hair loss in women usually begins with hair thinning on the crown. As this diffuse hair loss progresses, the scalp becomes increasingly visible. Unlike men, women with androgenetic alopecia generally do not experience receding hairlines or instances of complete baldness.

Managing and Treating Androgenetic Alopecia

Hair loss management can be pretty challenging. If you are concerned with hair loss, you should start by speaking with a hair loss doctor or trichologist (a hair and scalp specialist). These medical professionals are familiar with the genetics of AGA and can usually counsel a patient regarding the onset and progression of male and female pattern baldness.

When it comes to treating hair loss, earlier intervention often helps to preserve the hair you have left and prevent further hair loss. There are various surgical and non-surgical treatment options available for AGA. 

Medication for Hair Loss

Popular medications for the treatment of androgenetic alopecia include the following.

  • Minoxidil. A topical or oral medication that stimulates hair growth, increases blood flow in the scalp, reverses follicle miniaturisation, and prolongs the anagen phase of the hair life cycle. 
  • Finasteride and Dutasteride. Oral medications that stimulate hair growth while also inhibiting 5α reductase enzymes (type 2 and type 1 and 2, respectively) to decrease DHT levels.

Surgery for Hair Loss

If you experience severe hereditary hair loss and are unhappy with your appearance, you might be interested in hair transplantation. Getting a hair transplant from a reliable specialist will provide you with effective long-term results and help restore your confidence. 

There are two main types of hair transplants — FUT (follicular unit transplant) and FUE (follicular unit extraction). Here are some key points about these different techniques.

Follicular Unit Transplant

  • A traditional hair transplant method
  • Involves harvesting a strip of skin with healthy hair from the donor area
  • Results in a linear scar
  • Has a longer healing period

Follicular Unit Extraction

  • A more advanced hair transplant method
  • Involves extracting individual healthy hair follicles
  • Results in minimal scarring
  • Has a shorter healing period

Are you looking for hair restoration solutions? Dr Bonaros is a hair loss specialist servicing patients in Glasgow and all around Scotland. Schedule a consultation to get a reliable diagnosis and discuss your hair loss treatment options, including an FUE hair transplant.

Hereditary Hair Loss - FAQs

Dr Bonaros often gets asked questions like, “Is all hair loss genetic?” and “What is the biggest risk factor for hair loss?” If you want to know more about the relationship between hair loss, genetics, and biology, read our answers to some common questions below.

What is baldness in biology?

Baldness is another term for alopecia. While it is often associated with a complete loss of hair, there are actually several different types of baldness, including the following common hair loss conditions.

  • Androgenetic alopecia. This hereditary baldness in females and males causes progressive hair thinning and loss on the front and top of the head.

  • Alopecia areata. Linked to an autoimmune disease that attacks hair follicles, this condition results in unpredictable and patchy hair loss.

  • Cicatricial alopecia. Also called scarring alopecia, this condition is caused by inflammation, which destroys hair follicles and leads to permanent loss of hair and scarring.

What is considered premature hair loss?

People naturally lose hair all the time. In fact, it is normal to lose up to 100 strands of hair per day. However, if you notice that you’re losing more hair than this, you may be experiencing the beginning stages of balding. 

Many people will start to notice hair loss during their 30s and 40s. This increases with age and is generally most significant from the age of 60 onwards. However, this process differs for everyone. When it comes to early hair loss, genetic predisposition can influence your chances of premature balding. 

In some cases, individuals can even begin experiencing hair loss during their teens. If you are worried about experiencing early-onset androgenetic alopecia, it is wise to consult a medical professional. They will be able to confirm if you have started balding and, if so, can advise you on how to deal with this

Dr Bonaros performing FUE hair transplant surgery

Is all alopecia genetic?

No, not all cases of alopecia are genetic. While certain types of hair loss like male and female baldness are hereditary, this isn’t true for all conditions. For example, telogen effluvium is a temporary hair loss condition that is caused by stress.

When it comes to hereditary alopecia, it is also important to ask, “Is hair growth genetic?” Genetic factors play a big role in the appearance of your hair, including traits like texture and hair thickness. A genetic predisposition to certain hair traits can impact your chances of experiencing hair loss or hair growth disorders.

Besides genetics, there are also other risk factors that can influence hair loss. These include your general health, lifestyle, and environment. For example, if you have an unhealthy diet, you may develop vitamin deficiencies that can cause you to start losing your hair. 

Dr Bonaros: A Hair Restoration Specialist Who Cares

Dr Bonaros is a leading hair restoration specialist based in Glasgow. He is passionate about helping patients restore their confidence and offers surgical and non-surgical treatment plans that are tailored to suit each person’s individual needs. 

As a full member of the British Association of Hair Restoration Surgery (BAHRS) and Scotland’s only full member of the International Society of Hair Restoration Surgery (ISHRS), Dr Bonaros has expertise you can trust. 

Are you suffering from a genetic hair loss condition like androgenetic alopecia? Book a consultation with Dr Bonaros to receive a tailored treatment plan. Alternatively, please fill out our online assessment form and get advice directly into your inbox.

The article contains excerpts copied from the International Society of Hair Restoration Surgery,, © 2004.

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