Detailed answer

During menstruation, hormonal fluctuations can trigger an increase in melanin production in the skin, leading to hyperpigmentation. This is particularly true for individuals who are already predisposed to developing hyperpigmentation. Estrogen and progesterone levels fluctuate during the menstrual cycle, and these hormones can stimulate the production of melanocytes, the cells responsible for producing melanin. Additionally, the rise in androgen levels around the time of menstruation can cause oiliness and increased sebum production, which can further worsen hyperpigmentation. It is important to protect the skin with sunscreen and use products containing ingredients like niacinamide or vitamin C to help control melanin production and reduce the appearance of hyperpigmentation during this time.