Hair does not grow constantly. It alternates periods of great vitality and periods of rest, when it is normal to lose 50 to 100 hairs per day, which – having completed their life cycle - are immediately replaced. It is therefore equally normal to notice an increase in hair loss in autumn. Boldness, also known as alopecia or hair loss, consists in the absence of hair in areas of the scalp where it is normally present. The causes of hair loss may be temporary, as a result of periods of fatigue or stress or changes in hormonal activity with a reduction, especially in women, in the production of estrogens, as is the case after delivery or after menopause. With ageing, when, because of a slowdown in cell activity and the action of free radicals, the hair stem weakens and becomes thinner, growing much slower and therefore resulting in sparse hair.