With each change of season, hair loss can appear and become a source of anxiety for both women and men. Hair loss is actually normal and can be triggered by a number of factors. There is no miracle cure for hair loss, but it can be prevented.
In summer, we are much more exposed to the sun, which stimulates hair growth.
Less sunshine
When autumn comes, the reduction in sunlight leads to hormonal fluctuations, in particular a drop in melatonin production. When the days get shorter, particularly as autumn approaches, melatonin production decreases, which has an influence on the hair cycle. These hormonal variations disrupt the hair's natural balance, causing it to fall out more quickly (telogen phase).
Loss of tone
A drop in energy can also be responsible for hair loss. Stress and a return to a faster pace of work at this time of year can also lead to increased hair loss.
Vitamin deficiency
As the seasons change, particularly with falling temperatures and less sunshine, our intake of certain vitamins tends to fall. Vitamin D, for example, is mainly synthesised by the skin through exposure to the sun's UVB rays. In winter, the lack of sunlight reduces this synthesis, which can lead to a vitamin D deficiency. Similarly, during the cold seasons, our diet is generally less rich in colourful fruit and vegetables, which are sources of vitamins A and C.
All these vitamins play a crucial role in hair health, with vitamin A in particular acting on Wnt/β-catenin signalling, an essential pathway for the activation of hair follicle stem cells and the transition to the growth phase (anagen).
Vitamin C: As a powerful antioxidant, vitamin C acts against oxidative stress, which can accelerate hair loss. Studies show that this vitamin stimulates expression of the growth factor IGF-1, which promotes healthy hair growth (3).
Vitamin D: influences the hair growth cycle by regulating the transition between growth and rest phases. A lack of vitamin D affects the length of the growth phase, which can contribute to hair loss.
Diet and nutritional deficiencies
A diet lacking in protein, iron, zinc, or B vitamins weakens the hair fibre. These deficiencies often become apparent at the end of winter, making hair more vulnerable and therefore more prone to falling out.
External aggressions
UV rays, pollution, climatic variations, salt, and chlorine can weaken keratin. After the summer, for example, damaged hair falls out more quickly, which is why hair loss is often more pronounced in September and October.
