At the base of the epidermis, there are cells capable of synthesizing pigment called melanocytes. These cells have extensions with vesicles that reach the upper layers of the epidermis and release the pigment they produce into the cells. Pigment is essential for the skin because it absorbs UV radiation, protecting the genetic material in cell nuclei from damage.
In the process of melanogenesis in our skin, the amino acid tyrosine forms the pigment melanin, which occurs in the human epidermis in two variants: black or brown eumelanin and orange-red pheomelanin. The proportions between the amounts of these two types of melanin and the way they are distributed in the epidermis determine the color of our skin, hair, and eye irises.
Many genes influence melanin synthesis, determining our complexion—skin and hair color, characteristic of different races inhabiting distinct regions of the world. Additionally, hormones such as melanotropic hormone (MSH) and the sensitivity of certain receptors on epidermal cells influence pigment synthesis. For example, the PAR-2 receptor present on cells in the granular layer of the epidermis signals cells to absorb pigment, which then locates itself above the cell nucleus, protecting the cell's DNA from the negative effects of UV radiation.
The natural color of our body results from the transmission of red hemoglobin through the light-scattering epidermis and the presence of the two mentioned types of melanin. In some areas, the epidermis has a different structure, and light is not scattered, such as on the tongue and lips, which is why they have a pink or red color.
Apart from these intrinsic factors, external factors like diet, medications, and radiation also influence the color of our skin and hair. We can intentionally modify color using artificial or natural dyes, such as self-tanners, henna, hair dyes, but this will only be a temporary effect until the dye is washed out of the hair shaft or the upper layers of the epidermis are shed.
Where do discolorations come from?
In response to UV radiation, melanin present in the lower layers of the epidermis is distributed from melanocytes to the higher layers of keratinocytes (cells building the epidermis). Simultaneously, the process of melanogenesis intensifies. When there is an excessive production of melanin and its accumulation in clusters, hyperpigmentations (skin discolorations) are formed. These can take the form of single or merged spots, freckles, age spots (also associated with aging processes), or melasma, which are dark discolorations linked to hormonal disturbances.
Excess melanin can accumulate in the epidermis (mainly in the lowest basal layer), in the dermis (largely located in the upper layers, near blood vessels), or it can be a mixed dermo-epidermal pigmentation.
Discoloration can result from: ‣ Excessive melanin production by properly structured melanocytes, ‣ Damage to melanocytes and, consequently, intensified melanin production in them, ‣ Improper distribution of melanin to epidermal cells.
Hyperpigmentations can appear due to various factors of different nature: • Frequent mechanical injury to the skin, • Chemical action - locally or orally applied photosensitizing or photosensitizing substances (e.g., retinol, coumarins), • Excessive UV radiation exposure, • Chronic inflammatory conditions in the skin (e.g., acne changes - bumps, pimples, or diseases affecting the skin's immune system), • Excessive dose of infrared, heat energy (prolonged heating).
The main goal of reducing discolorations is to "break down" clusters of accumulated melanin and mobilize cells with an excess of pigment to shed. Additionally, it is important to influence the melanin production pathway to prevent excessive production.
According to specialists, deeper discolorations may require therapy lasting even 2-4 years, while epidermal ones can be completely removed with properly selected treatments and care within 6-12 months. At home, we can support skin tone leveling by using substances that break down melanin clusters, such as tranexamic acid or vitamin C. However, it's essential to remember that professional therapies such as chemical peels and laser discoloration removal are the most effective. Home care is supportive and preventive. Examples of substances with discoloration-lightening and excessive melanin production-inhibiting effects, proven in clinical studies, are ingredients found in Krayna products, such as Kakadu plum extract and common wheat germ extract.
