Quick answer. Excessive hair growth in women (hirsutism) is most often caused by polycystic ovary syndrome (PCOS) and androgen (male hormone) excess, with idiopathic and medication causes also common; the biggest red flag is rapid onset with voice deepening, balding, or increased muscle, which needs urgent hormonal assessment.
Hirsutism is the growth of coarse, dark hair in women in a pattern more typical of men, such as on the face, chest, abdomen, or back. It is usually driven by androgens (male-type hormones), which all women have in small amounts, becoming more active or being produced in higher quantities. It is a common concern and is frequently linked to an underlying hormonal condition.
In Singapore, women often see a GP, gynaecologist, or endocrinologist about unwanted hair growth, and it is worth investigating because the most common cause, PCOS, also affects periods, fertility, and metabolic health. This guide explains androgen excess, the usual causes, and the warning signs that mean you should be assessed sooner rather than later.
At a glance
| Pattern | Possible cause | Suggested action |
|---|---|---|
| Gradual hair growth with irregular periods | Polycystic ovary syndrome (PCOS) | See a doctor for hormone and ultrasound review |
| Hair growth with normal hormone levels | Idiopathic hirsutism | Confirm with a doctor; treatment available |
| Started after a new medication | Medication-related hair growth | Review medication with your doctor |
| Rapid onset with voice deepening or balding | Possible adrenal or ovarian tumour | Urgent hormonal assessment |
| Hair growth with weight gain and easy bruising | Possible Cushing's syndrome | See a doctor for evaluation |
Red flags: when to seek help urgently
Most hirsutism develops gradually and is not an emergency, but certain features point to a more serious hormonal cause and need prompt assessment:
- Rapid onset of hair growth over weeks to months, rather than gradually over years, is a warning sign.
- Signs of strong androgen excess (virilisation) such as a deepening voice, balding at the temples, increased muscle bulk, or enlargement of the clitoris need urgent hormonal assessment, as they can rarely indicate an androgen-producing tumour of the ovary or adrenal gland.
- Hair growth with unexplained weight gain, easy bruising, a rounded face, and muscle weakness may suggest Cushing’s syndrome and warrants evaluation.
These red flags are uncommon, but they are the reason a new or rapidly progressing change should be checked rather than only treated cosmetically.
Understanding androgen excess
All women produce small amounts of androgens such as testosterone, from the ovaries and adrenal glands. Hirsutism happens when there is either too much androgen circulating, or when hair follicles are unusually sensitive to normal androgen levels. Androgens convert fine, pale hair into coarse, dark hair in androgen-sensitive areas like the face and trunk.
This is why assessment often includes blood tests for hormone levels alongside a review of your periods, weight, and other symptoms. Understanding whether androgens are raised, and why, guides both the diagnosis and the treatment.
Polycystic ovary syndrome (PCOS): the most common cause
PCOS is by far the most common cause of hirsutism in women. It is a hormonal condition that typically combines excess androgen activity with irregular or absent periods and, on ultrasound, ovaries with many small follicles. Alongside unwanted hair growth, it can cause acne, weight gain, and difficulty conceiving.
PCOS also has metabolic links, including a higher risk of insulin resistance and type 2 diabetes, so diagnosis matters beyond the hair itself. Management may combine lifestyle measures, hormonal treatment such as the combined pill, anti-androgen medication, and care for fertility or metabolic health where relevant.
Idiopathic and medication-related causes
In idiopathic hirsutism, hair growth occurs despite normal androgen levels and regular periods, often because hair follicles are simply more sensitive to androgens. This is a common, benign cause once other conditions have been excluded, and it still responds well to treatment.
Certain medications can also promote hair growth, including some hormonal treatments and steroids. If excessive hair growth began after starting a new medication, mention this to your doctor, who can review whether the medication is contributing and discuss alternatives.
Rarer causes: tumours and Cushing's syndrome
Uncommonly, hirsutism is caused by an androgen-producing tumour of the ovary or adrenal gland. These typically cause rapid hair growth and other signs of strong androgen excess, such as a deepening voice and balding, which is why those features are treated as red flags requiring urgent assessment.
Cushing’s syndrome, caused by prolonged high levels of the hormone cortisol, can also produce excess hair along with weight gain, a rounded face, easy bruising, and muscle weakness. Both of these causes are rare, but they highlight why a sudden or severe change should be evaluated by a doctor rather than assumed to be cosmetic.
Which specialist should you see?
Because hirsutism is usually driven by a hormonal cause, an endocrinologist (hormone specialist) is well placed to investigate androgen excess, PCOS, thyroid issues, and rarer causes such as adrenal disorders or Cushing’s syndrome. Where the cause is gynaecological, such as PCOS affecting periods and fertility, a gynaecologist also plays a key role, and the two specialties often work together.
See our directories of the best endocrinologists in Singapore and the best gynaecologists in Singapore to find the right doctor. If hair growth is rapid or comes with voice deepening, balding, or increased muscle bulk, seek assessment promptly.
What to expect at the appointment
An assessment for hirsutism usually begins with questions about when the hair growth started and how quickly, your menstrual pattern, weight changes, acne, family history, and any medicines you take. The doctor may examine the areas affected and look for other signs of hormone imbalance. Blood tests for hormone levels such as testosterone are common, and an ultrasound of the ovaries may be arranged if PCOS is suspected. Bring a record of your recent periods and a list of your medicines, as this helps the diagnosis.
Managing unwanted hair while you are assessed
Cosmetic measures can be used alongside any medical treatment, as they manage the hair itself rather than the cause. Shaving, plucking, waxing, threading and depilatory creams are all reasonable choices and, despite the common myth, shaving does not make hair grow back thicker. Longer-term options such as laser hair reduction work best on dark hair and are available at many clinics in Singapore. If a hormonal cause such as PCOS is found and treated, hair growth often improves gradually, though it can take several months to see a difference.
Common questions
Is hirsutism always caused by PCOS?
No. PCOS is the most common cause, but hair growth can also be idiopathic (with normal hormone levels), medication-related, or rarely due to other hormonal conditions, which is why assessment is worthwhile.
How long does treatment take to work?
Hormonal treatments usually take several months to show an effect, because they slow new hair growth rather than removing existing hair. Cosmetic methods can be used in the meantime.
Will losing weight help?
For women with PCOS, even modest weight loss can improve hormone balance and symptoms, alongside any medical treatment your doctor recommends.
Related guides
- Best Endocrinology & Diabetes Clinics in Singapore — our editorial shortlist
- endocrinology & diabetes clinics directory
- Find a gynaecologist
- Find a gynaecologist
- Find a urologist
Sources
- NHS: Hirsutism (excessive hair growth)
- NHS: Polycystic ovary syndrome (PCOS)
- Mayo Clinic: Hirsutism
- HealthHub Singapore
- SingHealth
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