Androgenetic alopecia (AA) is also known as male or female-patterned hair loss and is the most common cause of hair loss.

Cause

AA is inherited, which means it's passed down from one or both of your parents. In people who were assigned male at birth (AMAB), it is caused by hormonal changes where testosterone is converted to dihydrotestosterone (DHT), which acts on hair follicles to slow or stop hair production.

Other causes of other types of hair loss include:

• Thyroid abnormalities
• Low iron
• Vitamin deficiencies
• Medication or medical treatment side effects
• More rare forms of alopecia

It is important to rule out these other causes and ensure your hair loss is inherited. We recommend seeing your primary care provider for any additional testing.

Symptoms

AA is slow and progressive hair loss with no other symptoms. It presents differently whether someone was assigned male or female at birth. Note that hormone therapy for gender-affirming care can slow hair loss for AMAB people and induce it for AFAB people. 

AMAB: Hair loss occurs on the scalp, starting from the forehead and towards the top of the head. May have bald spots. 

AFAB: Hair loss is usually more widespread thinning of the hair on the top of the head. Bald spots are rare.