Hair loss in men is more common than in women. It usually occurs between the ages of 20 and 35 and initially locates on the forehead or the crown, thinning out over the years. If not treated, it can progress more or less rapidly to baldness. Hair loss in women is less frequent than in men and generally less localized and significant. It is mainly due to hormonal variations, but the abuse of aggressive hair treatments (coloring, bleaching, brushing...) or poor hygiene (diet, stress, fatigue...) can also aggravate the problem.