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Androgenetic Alopecia: Causes, Diagnosis & Treatment
Dr. Michael May (FRCS)
Medically reviewed by
Dr. Michael May (FRCS)
Updated on June 28, 2023

Androgenetic alopecia (AGA) is the scientific name for male pattern baldness and female pattern baldness, and it’s the most common cause of hair loss in both men and women [1]. It affects approximately 85% of men and 50% of women by the time they’re 50 [2-3]. In fact, by the age of 35, two-thirds of men see some degree of noticeable hair loss.

Since pattern balding is so common, it’s normal to worry about whether your hair is thinning — or if you’re just paranoid. Some men start to lose hair in their teens or early twenties, so even if you’re young, you could already be seeing symptoms of androgenetic alopecia.

Androgenetic alopecia is a progressive condition that won’t get better without medical intervention. The earlier you seek treatment, the more likely you are to reduce and even stop your hair loss without needing a hair transplant.

Fortunately, there are many treatments available. In this guide, you’ll learn:

  • What causes androgenetic alopecia
  • Diagnosis of androgenetic alopecia
  • How to spot the symptoms of AGA versus other types of hair loss
  • Which treatments are effective for androgenetic alopecia.
Table of Contents

What causes androgenetic alopecia?

The exact cause of androgenetic alopecia is still being established, but most researchers agree AGA is caused by a combination of enzymes, hormones called androgens, and genetics.

Most people have an enzyme called 5-alpha reductase in their body, which converts testosterone to a male sex hormone or androgen known as dihydrotestosterone (DHT). DHT binds to androgen receptors in the hair follicles and causes them to miniaturise and stop producing hair [4-5]. When the hair follicle shrinks, it eventually stops producing hair which in turn leads to noticeable hair loss.

What are androgens and how do they affect hair loss?

Androgens are male sex hormones that cause men to develop typically male sex characteristics, such as facial hair, body hair, a deep voice, and a prostate gland. The major androgen in male development is testosterone.

DHT is a testosterone derivative, and is usually considered a key contributing factor to AGA. Men produce far more DHT than women, which is why men lose hair to AGA more frequently than women.

DHT binds to androgen receptors in your hair follicles. If your follicles are highly sensitive to androgens, hair from these follicles will fall out and eventually stop growing altogether.

It should be noted that there are still some unanswered questions about how and why DHT causes androgenetic alopecia. Testosterone and other androgens cause hair growth in other areas of the body at the onset of puberty. So some researchers suggest that DHT should theoretically have the same impact on scalp hair — causing it to grow, rather than fall out [4].

Is androgenetic alopecia genetic?

A growing body of evidence suggests that AGA is linked to genetics [6-8]. One large study of more than 52,000 participants found more than 200 genetic risk factors for male pattern baldness, indicating a strong genetic link with AGA that had previously only been suggested by small studies [8].

Many other studies confirm this link between inherited genes and AGA:

  • Twin studies suggest AGA is an inherited condition [9]
  • Genetic 5-alpha reductase enzyme deficiency — lower enzyme levels may make you less susceptible to AGA (although one study has disputed this link, the success of 5-alpha reductase inhibitors like Finasteride seems to confirm it) [10-12]
  • Aromatase gene — the aromatase enzyme converts androgens to oestrogen in women. Variation in this gene may increase the risk of developing female pattern hair loss [7].

What’s the biggest contributing factor for AGA?

Genes or hormones play a large part in the development of AGA. While most researchers agree that AGA is caused by a combination of both hormones and genetics, others are dissatisfied with this explanation, because androgens like DHT should theoretically cause hair to grow, not fall out [4].

An alternative theory suggests AGA is caused by pressure on the hair follicles created by the weight of the scalp [4, 13]. While you’re young, layers of fat under the skin protect the follicles from being pressed between the skin and the cranial bones. As you age, testosterone and its derivatives (such as DHT) cause this fat to erode. This compresses the hair follicles, leading them to stop producing hair. This explains why AGA only affects the hair on top of the head.

Lower prevalence and later onset hair loss in women is caused by high oestrogen levels, which protect the fat layers. Female pattern hair loss affects more women after menopause when oestrogen levels start to decrease.

However, this theory disregards the clear genetic influence on AGA development, which has been established in multiple studies [6-8]. Some researchers report that heredity accounts for approximately 80% of cases where the person is predisposed to AGA — so the importance of genes shouldn’t be underplayed [14].

Who can get androgenetic alopecia?

All teenagers and adults can develop androgenetic alopecia, though it’s usually more common in men than women. This is because men have higher levels of testosterone and therefore produce more DHT.

However, some men are at higher risk than others. Many studies have noted differences in AGA prevalence between men of different races and ages [14-17]:

  • Male pattern hair loss is more common in white men than in other ethnicities [14]
  • Black, East Asian, and Native American men are less likely to have extensive hair loss than white men [14]
  • In Japanese men, AGA occurs 10 years later than in white men on average — learn more about Asian hair loss [15]
  • Women over the age of 50 are more likely to develop female pattern baldness [16]
  • AGA hair loss is significantly higher in postmenopausal women [17].

How is androgenetic alopecia diagnosed?

Androgenetic alopecia is known as pattern baldness because it starts and develops in a specific way. People with AGA have a distinctive pattern of hair loss that differs from almost every other type of alopecia. This pattern differs in men and women and is usually easier to diagnose in men.

Androgenetic alopecia diagnosis in men

Men with AGA lose hair across the temples and crown. There are many models that show this, but the most commonly used is the Norwood Scale [18].

The Norwood Scale categorises hair loss into 7 distinct stages.

Norwood Scale for androgenic alopecia
Norwood Scale stages 1-7


Hair loss begins at the temples and recedes increasingly with each stage. In addition to a receding hairline, some men may also see a bald spot on their crown. AGA doesn’t usually affect the back and sides of the hair. At stages 6 and 7, hair loss on the temples and crown meet, causing partial or complete baldness across the scalp.

These celebrity hair transplant before and after photos show famous hairlines before they tackled their androgenetic alopecia. Here’s where they were on the Norwood Scale before their procedures:

Rob Holding before and after hair transplant
Rob Holding — Norwood stage 3.

Find out more about Rob Holding’s hair transplant at the Wimpole Clinic.

Elon Musk before and after hair restoration surgery

Elon Musk — Norwood stage 4 — learn more about Elon Musk’s hair transplant

Andros Townsend before and after hair restoration surgery

Although AGA is the most common type of hair loss, it’s not the only one. If your hair loss doesn’t follow this pattern, you may have another type of hair loss, such as alopecia areata, or alopecia barbae.

When you attend a hair loss consultation, your consultant will diagnose which type of hair loss you have. If you do have androgenetic alopecia, they’ll be able to confirm your Norwood stage, and discuss your hair loss treatment options with you.

Androgenetic alopecia diagnosis in women

Androgenetic alopecia follows a different pattern in women and often presents as thinning hair. This is often more difficult to diagnose. The pattern starts at the parting and eventually spreads across the scalp. This widespread, diffuse hair loss is similar to that seen in telogen effluvium (shock or stress-related hair loss).

A trichologist can determine whether you have female pattern baldness, telogen effluvium, or another type of hair loss. They’ll ask if you’ve recently experienced any stressful events that may have led to shock hair loss. They’ll also use the Ludwig Scale to measure and analyse your hair loss.

Ludwig Scale used to diagnose androgenic alopecia in women
Ludwig Scale stages 1-3


Female pattern hair loss starts with thinning around the parting, before progressing into visible hair loss across the scalp. As in male pattern baldness, the back and sides are usually unaffected.

Androgenetic Alopecia: Causes, Diagnosis & Treatment, Wimpole Clinic
Wimpole Clinic patients' female androgenetic alopecia prior to hair transplant surgery.

What happens if you don’t treat androgenetic alopecia?

While androgenetic alopecia can be very distressing, it rarely impacts your general physical health.

Most of the risks are psychosocial. AGA can lead to mental health issues like anxiety and depression [14, 19]. Hair transplant statistics also show that 40% of women with hair loss experience problems in their marriage as a result, and 63% say it’s had an impact on their career [19]. Men often cope well with AGA symptoms, though those with extensive hair loss or early onset are more likely to be distressed by their condition [14].

AGA is also a risk factor for other serious health conditions, especially in men. Associated conditions include [8, 14]:

  • Cardiovascular disease
  • Melanoma and non-melanoma skin cancer of the scalp (due to sun exposure)
  • Prostate cancer
  • High cholesterol
  • Ischemic heart disease
  • High blood pressure.

In women, female pattern hair loss is more likely to be associated with polycystic ovary syndrome (PCOS) and also hypertension and high aldosterone levels, which can lead to high blood pressure and low potassium levels [14, 20].

How do you treat androgenetic alopecia?

Unfortunately, AGA is permanent and irreversible. However, there are many treatments available to reduce and even prevent further hair loss.


Minoxidil is a topical solution that can reduce hair loss and stimulate hair growth when applied to the scalp every day. It’s available in 2 strengths — 2% and 5% — and is suitable for both men and women.

Minoxidil is often effective, especially in those with limited hair loss. One study found it to be at least moderately effective in 84% of AGA patients [21]. It’s also suitable for treating other hair loss conditions like telogen effluvium and alopecia areata.


Finasteride is a 5-alpha reductase inhibitor. Taken as a tablet, it suppresses the effects of the 5-alpha reductase enzyme, causing less testosterone to be converted to DHT [12].

Finasteride is one of the most effective treatments for AGA. One study found that taking 1mg of Finasteride a day prevented hair loss for up to 10 years without any other treatment or intervention [22].

It should be noted that Finasteride can cause serious side effects, including erectile dysfunction and excess hair shedding. As a result, many men consider taking Finasteride just 3 times a week. However, this isn’t recommended, as the dosage is formulated to be taken once a day. Lowering your dosage is less likely to stop or slow your hair loss.

Finasteride is usually only prescribed to men. Although it may be suitable for some women, 5-alpha reductase inhibitors can cause feminisation of male foetuses, and interfere with hormonal contraception [23-24]. So other hair loss treatments are usually preferred to avoid complications in contraception and pregnancy.


Dutasteride is another type of 5-alpha reductase inhibitor. While it works in a similar way to Finasteride, it has been shown to be slightly more effective [25-26]. In fact, a comparative study of Dutasteride, Finasteride, and Minoxidil found Dutasteride to be the most effective non-invasive treatment for androgenetic alopecia [27].

Find out more about the effectiveness of Finasteride vs Dutasteride for hair loss.

Anti-androgens for women

While 5-alpha reductase inhibitors are rarely suitable for women experiencing female pattern hair loss, anti-androgens and androgen receptor blockers are often effective. Drugs like Flutamide, Cimetidine, Cyproterone Acetate, and Spironolactone for hair loss have been shown to reduce AGA symptoms in women [23, 28].

These drugs work by lowering the androgen levels in your body or reducing androgen receptor sensitivity in the hair follicles. While they tend to be effective, there are often side effects, including sickness, breast tenderness, weight gain, and even liver damage. As a result, these aren’t usually first-line treatments for AGA patients.

Caffeine shampoo

Caffeine shampoo for hair loss is available over the counter, so it’s often one of the first treatments people try when they notice their hair falling out in the shower. Topical solutions containing caffeine can be effective for hair growth with sustained use over a 6 month period [29-30]. Some studies have found results comparable to Minoxidil, so this is an excellent option if you’re in the early stages of hair loss [31].

Learn more about caffeine and hair loss.

Botox injections

Botox for hair has been shown to successfully treat androgenetic alopecia in men. While this treatment isn’t a common treatment, it may be effective if you’ve exhausted other non-invasive solutions.

Can you get a hair transplant if you have androgenetic alopecia?

If you’re still young or don’t have extensive hair loss, it may be too early to get a hair transplant.

If your hair loss has already progressed beyond the initial stages on the Norwood or Ludwig Scale, a hair transplantation surgery is often the only way to restore your hair. Hair transplant success rates are often 90% or above, so it’s one of the most reliable, effective ways to tackle androgenetic alopecia.

Who can get hair restoration surgery?

Most AGA patients are good candidates for hair restoration surgery. Your eligibility will depend on how much hair you’ve lost, and how much hair you have in your donor area.

The average donor area contains 10,000-15,000 follicular units, and only 25% of this should be used in one procedure [32-33]. So if you need more grafts than this to cover your balding areas, you may not be an ideal candidate for hair transplantation surgery. In these cases, you may still be eligible for scalp micro-pigmentation, which gives you the appearance of full coverage if you wear your hair very short.

Find out when it’s too late to have a hair transplant.

Are you eligible for hair restoration surgery?

If your androgenetic alopecia is causing you distress, it’s time to find out if you’re eligible for hair restoration surgery.

At the Wimpole Clinic, our hair transplants far surpass the average clinic success rates, with 97-100% success. Led by our principal surgeon Dr. Michael May, our team is ready to support you through the process — from diagnosis to treatment to aftercare.

Book a free consultation at the Wimpole Clinic on Harley Street and find out if you’re eligible for a hair transplant to treat your androgenetic alopecia.

Androgenetic Alopecia: Causes, Diagnosis & Treatment, Wimpole Clinic

  1. Alopecia in Women
  2. Introduction To Androgenetic Alopecia
  3. Female Pattern Hair Loss: A Retrospective Study in a Tertiary Referral Center
  4. Cause of Androgenic Alopecia: Crux of the Matter
  5. Balding hair follicle dermal papilla cells contain higher levels of androgen receptors than those from non-balding scalp
  6. Molecular mechanisms of androgenetic alopecia
  7. Gene-wide association study between the aromatase gene (CYP19A1) and female pattern hair loss
  8. Genetic prediction of male pattern baldness
  9. Genetic Basis of Male Pattern Baldness
  10. Medical Treatments for Balding in Men
  11. Genetic Analysis of Male Pattern Baldness and the 5α-Reductase Genes
  12. Finasteride, a Type 2 5alpha-reductase inhibitor, in the treatment of men with androgenetic alopecia
  13. Baldness may be caused by the weight of the scalp: gravity as a proposed mechanism for hair loss
  14. Male Androgenetic Alopecia
  15. Progressive decrease in hair diameter in Japanese with male pattern baldness
  16. Hair density, hair diameter and the prevalence of female pattern hair loss
  17. Frequency, severity and related factors of androgenetic alopecia in dermatology outpatient clinic: hospital-based cross-sectional study in Turkey
  18. Classifications of Patterned Hair Loss: A Review
  19. The psychological impact of alopecia
  20. Aldosterone and the Risk of Hypertension
  21. A one-year observational study with minoxidil 5% solution in Germany: results of independent efficacy evaluation by physicians and patients 1
  22. Long-term (10-year) efficacy of finasteride in 523 Japanese men with androgenetic alopecia
  23. Hormonal therapy in female pattern hair loss
  24. Contraindicated use of 5‐alpha‐reductase inhibitors in women
  25. A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia
  26. The efficacy and safety of dutasteride compared with finasteride in treating men with androgenetic alopecia: a systematic review and meta-analysis
  27. Relative Efficacy of Minoxidil and the 5-α Reductase Inhibitors in Androgenetic Alopecia Treatment of Male Patients
  28. Treatment of female androgenetic alopecia with cimetidine
  29. Efficacy of a cosmetic phyto-caffeine shampoo in female androgenetic alopecia
  30. Efficacy of a cosmetic caffeine shampoo in androgenetic alopecia management
  31. An Open-Label Randomized Multicenter Study Assessing the Noninferiority of a Caffeine-Based Topical Liquid 0.2% versus Minoxidil 5% Solution in Male Androgenetic Alopecia
  32. Approach to Hair Transplantation in Advanced Grade Baldness by Follicular Unit Extraction: A Retrospective Analysis of 820 Cases
  33. Complications in Hair Transplantation
Dr. Michael May (FRCS)
Medically reviewed by Dr. Michael May (FRCS)Updated on June 28, 2023
The Wimpole Clinic offers FUE Hair, Beard & Eyebrow Transplants & Trichology.
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