All female people have body hair. However, it may be more noticeable in some than in others and include growth on the face. Hirsutism is when this hair growth becomes excessive.

All people experience typical hair growth on their bodies as they mature sexually. Hirsutism happens when hormones cause hair to grow in the female body after puberty in areas where it typically only grows in males.

Hirsutism can occur due to a number of underlying medical conditions. In some cases, there may not be an underlying cause. A person can remove unwanted hair cosmetically, and it is up to them to decide whether or not they wish to receive further treatment.

Androgens are sex hormones that help develop the reproductive system and secondary sexual traits of males after puberty. One of the most common types of androgens is testosterone. Though doctors may refer to androgens as male hormones, they are present in both male and female bodies.

Both sexes are responsible for hair growth under the arms and in the pubic area after puberty. In males, they also stimulate the growth of other body hair, as well as facial hair such as mustache and beard.

Several medical conditions can cause people assigned female at birth to produce too many androgens and grow excessive hair.

Polycystic ovary syndrome (PCOS)

The most common cause of excess body hair in people assigned female at birth is polycystic ovary syndrome (PCOS), which is a hormonal disorder causing the body to produce too many androgens. The condition accounts for more than 70% of hirsutism cases.

Doctors do not fully understand the causes of PCOS. However, a person can manage the symptoms with birth control pills or other hormonal treatments.

Congenital adrenal hyperplasia

Congenital adrenal hyperplasia is a rare group of disorders that affect the adrenal glands and can cause severe symptoms.

The female body may produce too many androgens when the adrenal glands do not work correctly. This can lead to a variety of symptoms, including excessive hair growth.

Doctors do screen for conditions that cause adrenal hyperplasia. However, mild cases may not be possible to diagnose until puberty.

Tumors

According to the American Academy of Family Physicians, 0.3 percent of hirsutism cases happen due to a tumor that releases androgens.

The body hair appears rapidly in these cases and may include other symptoms, such as a mass in the stomach or pelvis.

Medication

Some medications can cause additional hair growth. A person who notices new hair growth after trying a new prescription drug should tell their doctor.

Some drugs with links to hirsutism include:

  • certain antipsychotic drugs
  • glucocorticosteroids
  • certain anti-seizure medications
  • certain immunosupressive medications
  • hormone drugs, such as testosterone, plus some drugs that alter hormone production

Hyperprolactinemia

Hyperprolactinemia is a condition that causes the body to produce high levels of the hormone prolactin.

Prolactin is primarily responsible for producing breast milk in breastfeeding people. People with this condition may lactate even if they are not nursing.

Some people with hyperprolactinemia may experience infertility or not have their periods. The condition can also cause hirsutism.

Thyroid disorders

The thyroid produces hormones that help regulate metabolism and body temperature. The two common thyroid disorders are hyperthyroidism and hypothyroidism.

When the thyroid malfunctions, it may create an imbalance of hormones that causes excess body hair growth in rare cases.

Other causes

Sometimes hirsutism has no apparent cause, and doctors can find no clear evidence of an underlying disorder. When hirsutism has no clear reason, a doctor may refer to it as idiopathic hirsutism.

This is typically a diagnosis of exclusion when a doctor can eliminate all known, possible underlying causes. Idiopathic hirsutism represents about 10% of all cases of hirsutism and 50% of all mild cases of excessive hair growth.

When the cause of hirsutism is unknown, it may be genetic. People of East Indian and Mediterranean origin who were assigned female at birth tend to have this type of hair growth.

It can be challenging to determine what counts as excessive body hair. It is typical for female people to have fine hair all over the body, including the face. Many may also notice thicker, darker hairs on the stomach, chin, and chest.

The Ferriman-Gallwey scale

To help classify what counts as hirsutism, researchers developed the Ferriman-Gallwey scale. This scale assigns a score based on how much hair growth a person has on various body areas.

According to the scale, fine hair is “normal,” as are a few coarse strays. It is more likely to be a problem when hair is thick on many areas of the body. A score greater than 7 is typically indicative of excessive hair growth or hirsutism.

The original scale was developed in 1961. It involves measuring the volume of hair growth at 11 sites in the body susceptible to androgen-related hair growth. Researchers later reduced this scoring system to focus on just nine areas, leading to what is now known as the modified Ferriman–Gallwey score.

Variation across populations

However, research has shown that the cut-off score of 8 may not be applicable for people of different ethnicities and racial groups who were assigned female at birth. Some populations may be naturally predisposed to variable levels of hair growth.

People of Middle Eastern, Mediterranean, or Hispanic descent who were assigned female at birth typically need a score of 9 or above for hair growth to qualify as excessive.

The cut-off score for South American people assigned female at birth is 6, whereas the cut-off score is 2 for Asian people. In the United States and the United Kingdom, the standard cut-off score is 8 for both Black and white people.

Beyond the scale

Generally, any cut-off score under 15 may indicate mild hirsutism, and a score over 25 can indicate severe hirsutism. However, clinical practices by the Endocrine Society suggest that regardless of the scale, any person assigned female at birth who feels they have abnormal hair growth should speak to a medical professional.

Furthermore, the doctor’s decision to refer their patient to testing or treatment should be patient-focused, meaning based on how the patient experiences the condition’s symptoms.

If a person is troubled by their symptoms despite cosmetic measures, a doctor should refer them to testing and treatment.

In addition to looking at the Ferriman-Gallwey scale, a doctor will diagnose hirsutism usually by excluding other causes for excessive hair growth. If an initial exam suggests a person has excessive hair growth, a doctor must then look for the reason.

Tests may include:

  • thorough physical exam
  • questions about the patient’s family history of similar symptoms, symptom onset, and any medications they may be taking
  • bloodwork to measure androgen and other hormone levels
  • charting of a person’s periods and obtaining a detailed menstrual history
  • imaging scans to check for tumors and other growths
  • pelvic exam in which the doctor will look for signs of androgenization or tumors

Natural treatments can help with unwanted hair growth due to PCOS.

These include:

  • Diet changes: For people assigned female at birth who have insulin resistance, reducing their intake of sugars and carbohydrates can help. Some people also try specific PCOS diets. However, there is little research on how well these diets work.
  • Weight management: Maintaining a moderate weight can help control many symptoms of PCOS. For many people assigned female at birth, the right combination of diet and exercise may be key.
  • Mental health support: PCOS is a complex disorder that can change a person’s appearance, fertility, and health. Many people find that support groups, therapy, and positive self-talk help.

Hair removal methods, such as shaving or using hair removal creams, can be effective. However, these methods will not address the underlying cause of excess hair growth.

People without a diagnosis or who have an underlying medical condition should talk with their doctors about medical treatment.

Medical treatments can help with excessive or unwanted hair growth due to PCOS. Many people assigned female at birth find that taking birth control pills helps to regulate their hormones and their periods while reducing hair growth. Others may need to use insulin to control diabetes.

Another medical treatment that might be useful is spironolactone, a drug that can control the effects of specific hormones. People who have PCOS and are trying to become pregnant may need artificial hormone treatments to induce ovulation.

When someone assigned female at birth has a condition other than PCOS, treatment depends on the disorder, their medical history, and other factors.

Hormone treatments can restore hormonal balance, though a person might also need additional treatments. For example, if there is a tumor that produces androgens, doctors may need to remove the tumor with surgery.

Hirsutism happens when someone assigned female at birth experiences the growth of excessive male-looking hair. When the cause is an underlying condition, a person can seek treatment for the underlying cause to reduce excessive hair growth.

Most hormonal disorders, including PCOS, respond to medical treatments. Proper treatment can reduce the amount of body hair a person experiences.

However, the definition of excessive hair growth is not always medical.

Almost all female people grow body hair, and even healthy people may grow much more body hair than they believe to be desirable. In many mild cases, hair removal methods make it possible to quickly eliminate cosmetic concerns of excess hair growth.

When a person is troubled by such hair growth and unable to control the hair growth cosmetically, this can be enough to qualify their condition as excessive hair growth and they can seek treatment.