What Causes Female Pattern Hair Loss?

Female pattern hair loss (FPHL) is also called female androgenetic alopecia (female AGA or FAGA). Three of the most common causes of FPHL appear to be age, heredity, and hormonal changes. However, causes are not as defined as in common male balding. Research suggests that chronic low-level inflammation in hair follicles and marginal iron deficiency may also contribute to FPHL. ^20, 30, 88

At least one study indicates that thyroid conditions are strongly associated with female pattern hair loss—more than any other type of alopecia. Some health conditions or procedures may cause excess androgens and female AGA. These include: ³⁰

• Adrenal or ovarian tumors³⁰
• 
  Congenital adrenal hyperplasia ³²
• Cushing syndrome ³²
• Hysterectomy ³⁰
• Insulin resistance (as with diabetes) ¹⁰⁰
• Metabolic syndrome ³⁵⁷
• Persistent adrenarche syndrome ³⁰
• Polycystic ovary syndrome (PCOS) ³²
• SAHA syndrome ³⁰

Environmental toxins may also play a role in FPHL. A study of hair follicles in women with this type of hair loss found excess aryl hydrocarbon receptors. These types of receptors can be activated by toxins and cause inflammation and cell death. ³⁷⁹

Research indicates that women with androgenetic hair loss can also experience telogen effluvium due to seasonal hair cycle changes. A six year study involving over 800 healthy women with thinning hair (79.2% of whom had female pattern hair loss) showed that the amount of hair entering the telogen phase is in July, with most shedding occurring during the autumn months. ⁷⁸