Medical aspects
Our skin's mass reaches about one fourth of our body weight and embraces our interior with an area of averaged 1.5 m² to 2 m². On only one cm², there are around 6 million cells building approximately 5000 sensorial bodies, 4 meters nerve fibres, 200 pain spots, 100 perspiratory glands 15 sebaceous glands, 12 cold points, 5 hairs and 2 heat points, necessary supply is based on 1 meter veins/arteries.
Basically, our skin is divided up into 3 layers:
| The dermis, the most interior layer is an approximately thick network of elastic connective tissue. Richly supplied with blood and provided with sensorial bodies as well as nerve fibres. Fixed collagen and flexible elastin fibres as well as full-of-water source molecules (glycosaminoglykanes) provide the necessary elasticity. All the components are produced by stromal cells (fibroblasts). Marks of aging (crinkles, slack skin) result from strand break and the fibres being stapled together and a reduced ability to absorb water of the source fibres. Hair roots, sebaceous glands and perspiratory glands belong to the epidermis and are countersunk in the dermis. |  |
| The epidermis is networked through a layer of around 0.1 mm with the dermis. This geared realm creates the necessary stability and provides the nutrient and oxygen supply. The base of the epidermis is built by the cells at the ground of this skin layer, they produce continually skin cells (keratinocytes), producing for the short duration of their lifetime fat substances for the skin barrier and the fibre substance keratin. Our immune and metabolism regulation is carried out by messengers who's origins are found here. Moreover, the origin of our tan is found here, as well, the melanocytes of transformers from amino acid to melanosomes. Our skin cells die off after only about 2 weeks and form as corneocytes, linked by lipids, the horny layer. | |
The horny layer (stratum corneum), died off skin cells, is what we focus all our attention on, be it its colour or its dimensional impressions, which are displayed through layer thicknesses of approximately 0.02 mm to 10 mm (weals). These died off skin cells (corneocytes) and the fat substances (epidermic lipids) inbetween protect us from loss of water (dehydration) and riot agents, allergens as well as germs. In order to maintain those protective functions mentioned above, this layer makes use of an acid mantle expressing itself in a pH-value. This natural acid mantle is best working at 5.5 . Counteracting against dehydration is the Natural Moisturizing Factor-NMF, additionally providing a further protection from dehydration.
Until now, people confined themselves in fields of dosimetry (defining duration of radiation) to paying attention only on exclusively visual (optical) impressions, be it with the eye mainly tan or via technology in the visual area (measurement with red, green, yellow and blue radiation). The result, in both cases, solely refers to dead matter, died off skin cells, providing a barrier to the environment.
| The training of the tan by UV radiation,however, is done in deeper, living cell structures, for our eye and also for visual measurement technology invisible. The relevance of the color of our horny layer and the conclusion of a tanning time is as irrelevant as the protection against UV radiation by means of self-tanner (peptides introduced in the horny layer). Tan is a waste product of a complex defense mechanism to protect our body. The adjoining melanocyte transforms in the basal cell layer in the epidermis, under the influence of UV radiation, amino acids to melanin precursors. The finger-like protuberances (dendrites) of melanocytes transport these melanin precursors to the pending keratinocytes. Here now surrounds the melanin, oxidized to the brown pigment, the cell nucleus, and thus protects the DNA found in the nucleus from UV radiation (light callosity). If UV radiation hits this cell nucleus, this leads to a degradation of DNA, in the positive case, the cell dies, in the negative case begins a risky cell proliferation. |  |
 | The irrelevance of the skin colour remains in the proper measurement of SkinControl secondary, primarily carried out to determine the thickness of the skin (pigmentation light callosity), the immune function of our skin against UV radiation. Existing measurement techniques can reach only colorimetry (visual colour impressions) and derive an immune function. Furthermore, SkinControl determines the proportion of melanin precursors, the resulting parameters allow an accurate determination of the threshold dose, a dose to the base, to reach tan - far away from erythema. Erythema result in cell injury and cell renewal, and the latter has a tan opposite function. SkinControl calculates the stock of nutrients in the skin, which are necessary for pigment formation. |
| The complexity of the formation of brownness becomes schematically transparent through the depiction of the 3 elementary effect spectra (1 UV erythema, 2 direct pigmentation and 3 delayed pigmentation). The delayed pigmentation is almost identical in its spectrum of activity to the UV erythema. This underlines the direct correlation between erythema and tanning the skin. The direct pigmentation, however, her spectrum of activity in the medium UV-B range and extends up into the blue light area. Ultimately, any cosmetic tanning brings both positive and negative aspects, whether the pigment formation (spectrum of activity of the delayed pigmentation), the formation of sunburn (spectrum of activity of UV erythema) and skin aging (spectrum of action of direct pigmentation) with itself. Because only the symbiosis of all spectra of action also lead to the browning. A depletion of the risks can only be achieved through a precise dosage of each radiation dose (limiting the tanning time). |  Range of action for the UV erythema (1), the direct (2) and the delayed pigmentation (3)(Source: UV fibula) |
 Browning without sunburn (Source: academy for tanning) | The frequently wanted instant tan, after a single tanning, is possible only to a very small (barely visible) extent. Tan comes from the interaction of the pigment formation and direct pigmentation. This requires not just minutes and hours but days. For example, the UV-erythema has a high initial tanning effectiveness, but this is reduced significantly after 3 tannings. This illustrates the high risk, especially for new customers because this often leads to overdose and sunburn. |