You recently wrote “Yes, any hormonal manipulation can cause hair loss”. can topical estrogen or estradiol cause hair loss in other parts of the body such as eyebrows & if so what are the chances that it would grow back.
Using estrogens, as in topical anti aging creams, has minimal systemic absorption and should not affect hair growth. Having said that, using topical estrogens for a long time or on a large area of the body may produce enough serum concentration and act like systemic drug. Estrogen is generally considered a protective hormone and hair loss is seen with its withdrawal, but playing with one hormone impacts other hormones and they might contribute to hair loss in special circumstances with some particular genetics influences (eyebrows or lashes). We know, for example, that female genetic hair loss is often not protected by estrogens.
Paid advertisements (not an endorsement):