Before explaining why menopause is the cause of skin losing its firmness, it is necessary to understand the role of hormones.
Under the influence of oestrogens, the fibroblasts present in the dermis synthesise more collagen fibres, elastin, as well as hyaluronic acid, providing the skin with improved density, elasticity and firmness. Furthermore, the oestrogens increase the number of keratinocytes whose role is to synthesise keratin, a protein that protects the skin.
The role of progesterone in relation to the skin is still not well understood. It appears that it increases sebum secretion.Furthermore, progesterone has a known anti-androgenic effect.
Thus, at the time of menopause, the cessation of ovarian activity leads to a drop inoestrogens and therefore a decrease in fibroblastic activity. The skin loses density, elasticity, and firmness.
Beyond this loss in firmness, the loss of hyaluronic acid and the inactivity of the sebaceous glands, the skin generates a dehydration and a weakening of the hydrolipidic film. This results from the deficiency in progesterone. The skin then becomes more susceptible to external aggressions and transepidermal dehydration.