Understanding the mFG Score
The modified Ferriman-Gallwey score adds up nine body areas, each rated 0 to 4, for a total from 0 to 36. Ferriman and Gallwey described the original 11-area scale in 1961, and Hatch and colleagues trimmed it to the nine androgen-sensitive areas used today in 1981.
| Score | Interpretation | What usually happens next |
|---|---|---|
| 0-3 | Below the cut-offs used in current guidelines | No workup needed for hair alone; local unwanted hair can still be treated cosmetically |
| 4-7 | Above the 4 to 6 threshold the 2023 international guideline uses for some populations, below the classic 8 | Worth discussing with a doctor, especially with irregular periods |
| 8-15 | Hirsutism, often called mild | Doctor's assessment; the Endocrine Society suggests testing androgen levels when the score is abnormal |
| 16-25 | Hirsutism, often called moderate | Endocrine evaluation and treatment options |
| 26-36 | Hirsutism, often called severe | Prompt endocrine evaluation, especially if it developed quickly |
Thresholds vary by ethnicity. The cut-off of 8 comes from studies of white and Black women in the US and UK. The 2023 International Evidence-based Guideline for PCOS says a modified Ferriman-Gallwey score of 4 to 6 should be used to detect hirsutism, depending on ethnicity, and notes that East Asian women tend to have less body hair, so a lower score can already be significant. The mild, moderate and severe labels are a common clinical shorthand, not formal guideline categories.
Worked example
A woman rates her upper lip 2, chin 2, lower abdomen 2, thighs 1, and every other area 0. Her total is 2 + 2 + 2 + 1 = 7. That is below the classic cut-off of 8 but at or above the 4 to 6 range the 2023 guideline uses. Combined with irregular periods, it would be reasonable to ask a doctor about PCOS and blood tests for androgens.
PCOS - Rotterdam Diagnostic Criteria
Diagnosis of PCOS in adults requires at least 2 of the following 3 (Rotterdam consensus 2003, refined by the 2023 international guideline):
- Ovulatory dysfunction: irregular or absent menstrual cycles.
- Clinical or biochemical hyperandrogenism: hirsutism, or raised androgen levels in a blood test. Acne and scalp hair thinning on their own are weaker signs.
- Polycystic ovarian morphology: 20 or more follicles in at least one ovary on a modern transvaginal ultrasound, or an enlarged ovary. Since 2023 a high anti-Müllerian hormone (AMH) level can be used instead of ultrasound in adults.
Other causes must be excluded first, including thyroid disease, high prolactin, non-classic congenital adrenal hyperplasia, Cushing's syndrome and androgen-secreting tumours. In adolescents, both irregular cycles and hyperandrogenism are needed, and ultrasound is not used for diagnosis within 8 years of the first period.
This tool is for information only. A checklist cannot diagnose PCOS; it can help you prepare for an appointment.
When to see a doctor quickly
See a doctor soon if hair growth started suddenly or is getting worse fast, or if it comes with a deepening voice, a growing muscle bulk, an enlarging clitoris or other signs of virilization. Rapid onset can point to an androgen-secreting tumour, which needs urgent assessment. Mention any medicines you take, since some can cause excess hair.